Loading...
HomeMy WebLinkAbout07-16-1996 PC Agenda I PLANNING COMMISSION Regular Meeting -Dublin Civic Center Tuesday- 7:30 p.m. 100 Civic Plaza, Council Chambers July 16, 1996 1. CALL TO ORDER 2. ROLL CALL 3. PLEDGE OF ALLEGIANCE TO THE FLAG 4. ADDITIONS OR REVISIONS TO THE AGENDA 5. MINUTES OF PREVIOUS MEETINGS -June 18, 1996 6. ORAL COMMUNICATION-At this time,members of the audience are permitted to address the Planning Commission on any item(s)of interest to the public;however,no ACTION or DISCUSSION shall take place on any item which is NOT on the Planning Commission Agenda. The Commission may respond briefly to statements made or questions posed,or may request Staff to report back at a future meeting concerning the matter. Furthermore,a member of the Planning Commission may direct Staff to place a matter of business on a future agenda. Any person may arrange with the Community Development Director(no later than 11:00 a.m.,on the Tuesday preceding a regular meeting)to have an item of concern placed on the agenda for the next regular meeting. 7. WRITTEN COMMUNICATIONS 8. PUBLIC HEARINGS 9. NEW OR UNFINISHED BUSINESS 9.1 Draft Eastern Dublin Comprehensive Stream Restoration Program -As the Eastern Dublin Specific Plan and Eastern Dublin General Plan Amendment/Specific Plan EIR requires, the City has completed a draft Eastern Dublin Comprehensive Stream Restoration Program. 10. OTHER BUSINESS (Commission/Staff Informational Only Reports) 11. ADJOURNMENT (OVER FOR PROCEDURE SUMMARY) i ICITY OF DUBLIN 1 PLANNING COMMISSION t AGENDA STATEMENT/STAFF REPORT Meeting Date: July 16, 1996 TO: Planning Commission FROM: Planning Staffeknio- PREPARED BY: Carol R. Cirelli, Seniorl. Planner SUBJECT: Eastern Dublin Comprehensive Stream Restoration Program RECOMMENDATION: 1) Hear staff presentation. 2) Take testimony from the public. 3) Question staff and the public. 4) Deliberate. 5) Adopt draft Resolution, Exhibit B, recommending City Council adoption of the Eastern Dublin Comprehensive Stream Restoration Program, and the Tassajara Creek Lower Reach Implementation Plan, Exhibit C; or give staff direction and continue the matter. GENERAL INFORMATION: PROJECT: As the Eastern Dublin Specific Plan and Eastern Dublin General Plan Amendment/Specific Plan EIR requires, the City has completed a draft Eastern Dublin Comprehensive Stream Restoration Program. LOCATION: Eastern Dublin Project Area BACKGROUND: The Eastern Dublin General Plan Amendment/Specific Plan and companion EIR requires the city to prepare and adopt certain implementation plans and programs before Eastern Dublin development occurs. In addition to the Grazing Management Plan and Wildfire Management Plan, the City has completed the Eastern Dublin Comprehensive Stream Restoration Program (Stream Restoration Program). The City hired the consulting firm of Sycamore Associates to prepare Stream Restoration Program for the Eastern Dublin General Plan Amendment area. Sycamore Associates is highly experienced ;•reparing stream restoration plans. Their project team, comprised of plant and animal biologists, hydrologic engineers, civil engineers, and planners, demonstrated a very good understanding of the Eastern Dublin General Plan Amendment/Specific Plan goals and action programs for preserving one of the City's most significant hydrological, biological, aesthetic and recreational resource, Tassajara Creek. Item No. • 1 Copies To: Project File Admin. File Senior Planner g:\eastdubl\stream\pcsr\crc PAGE OF ANALYSIS: EASTERN DUBLIN COMPREHENSIVE STREAM RESTORATION PROGRAM introduction The Eastern Dublin Specific Plan includes stream restoration policies for Tassajara Creek and its tributaries that promote the enhancement of these streams'natural functions as drainage channels, habitat areas,and wildlife corridors. The policies also promote the enhancement of the channels as aesthetic and recreational resources for the proposed Eastern Dublin community. Action Program 6F of the Eastern Dublin Specific Plan and Mitigation Measure 3.7/12.0 of the Eastern Dublin General Plan Amendment/Specific Plan EIR requires the City to develop a comprehensive stream corridor restoration program that includes a detailed set of criteria for grading,stabilization and revegetation of the planning area stream channels,and guidelines for plant species,planting densities, and long-term maintenance and responsibilities. The program is intended to facilitate project processing and ensure a consistent standard for stream channel improvements throughout the planning area. The City was required to develop this program while working cooperatively with the Alameda County Flood Control and Water Conservation District,Zone 7 Water Agency(Zone 7),the California Department of Fish and Game and the East Bay Regional Park District(EBRPD). The draft Stream Restoration Program,Exhibit A,contains guidelines and criteria for hydrology and water quality(reducing flood hazard,runoff water quality,soil and groundwater quality,channel stability and erosivity,etc.),planning(channel cross sections and stream setbacks,trails and maintenance roads,development interface,etc.(,and resource protection,restoration and mitigation. The document also contains an implementation(long-term management)and regulatory compliance chapter. Attachment 2 is a summary of the Stream Restoration Program standards,guidelines and recommendations. The consultants prepared the Stream Restoration Program through collaborative efforts with City staff,Zone 7,EBRPD,County of Alameda Public Works,California Department of Fish and Game, landowner representatives,Natural Resource Conservation Service and the East Bay Municipal Utilities District. The Stream Restoration Program supports the Specific Plan policies of designing and performing flood control maintenance practices to be responsive to public safety while preserving the unique riparian communities. It addresses the protection and enhancement of wildlife habitat,flood control management, public access(i.e.,local and regional trails accommodating pedestrian,equestrian and bicyclists)and the separation/buffering of wildlife habitat from incompatible human activities. The successful implementation of the Stream Restoration Program implementation will involve the participation,review and approval of various governmental agencies. For example,EBRPD,Zone 7,and the California Department of Fish and Game should review all development plans along the stream corridors. Additionally,appropriate regulatory agencies should review these plans as part of their agency's permitting process and the Stream Restoration Program strongly encourages early project design review and involvement of these agencies(see the"Regulatory Compliance"section of the Stream Restoration Program). The following sections summarize each agency's role. City of Dublin's Role The policies and guidelines of the Stream Restoration Program shall be enforced for all new rezone and tentative map applications for properties located within the Eastern Dublin Specific Plan area. The document presents suggested guidelines and criteria from which the City will base stream restoration, hydrologic and site planning/development setback requirements and conditions of approval for rezones and tentative maps. 2 PAGE_OF.___ For proposed development projects that are adjacent to Tassajara Creek or the creek's tributaries, the City will require as conditions of PD Rezone and Tentative Map approval,flood control,trail,road, revegetation,restoration,enhancement and landscaping improvements in compliance with the Stream Restoration Program. Appendix B of the Stream Restoration Program outlines the PD Rezone,Tentative Map and Final Map application submittal requirements for the stream corridor restoration. The Stream Restoration Program emphasizes that the stream portions of the Specific Plan area should not be fragmented from adjacent development during the planning and review process. The proposed creek hydrologic and revegetation improvement plans will be approved with the Final Map. Flood control improvements must be completed prior to issuance of building permits. Creek revegetation and landscaping improvements should be made concurrently with flood control improvements. This reinforces the state and federal regulatory requirements. If flood control improvements are not necessary for a particular project,the City will still require that revegetation improvements be implemented shortly after projects are developed. The City's main objective would be to apply these criteria and guidelines as the document recommends. However,the City may apply some flexibility implementing these guidelines and allow some guideline modifications,only if these changes meet the overall intent of the Specific Plan goals, policies and action programs,and Stream Restoration Program criteria and guidelines. The Stream Restoration Program acknowledges the potential for interrupting,or relocating the trails,creek crossings and maintenance road extensions due to private property,topographical or other site constraints. This interruption can occur as long as the trail/maintenance ingress and egress points are provided at the points of interruption. For example,one land owner was concerned that the regional trail extending along the rear portion of his property would impact his residential privacy. In this situation,the City would not extend the trail and maintenance roads along the rear of his property,or across any other properties that would result in property site impacts,condemnation and/or structure removal. However,this land owner would be required to comply with the Stream Restoration Program once he applies for rezone and tentative map approvals consistent with the Eastern Dublin Specific Plan. Zone 7's Role Zone 7's flood control mandate is that Tassajara Creek contain 100 year flood flows. Zone 7 will evaluate flood conveyance on behalf of the City and evaluate it for reaches which Zone 7 may own. Based on detailed hydrologic studies for each development proposal,Zone 7 will determine whether flood conveyance is adequate for the channel. Zone 7 will accept ownership and maintenance responsibility for flood control purposes for channels that have been improved to Zone 7 standards. Zone 7 has Special Drainage Area funding to take ownership of the lower creek reach(1-580 Fwy.to Gleason Drive.) This special funding area may be extended to cover a larger area along Tassajara Creek. It is possible that Zone 7 may acquire and maintain other portions of the creek from Gleason Drive to the Contra Costa County line. However,Zone 7 reviewed the site conditions of the upper reach(from the EBRPD staging area to the Contra Costa County line)and concluded that the severely eroded steep banks and other site conditions preclude their ownership. Zone 7 may more than likely own the lower and middle reaches. EBRPD's Role The Specific Plan requires the provision of a north-south trail along Tassajara Creek,and trails along other stream corridors within the Eastern Dublin project area. The Specific Plan intended that the required trail along Tassajara Creek become part of the EBRPD's regional trail network. The Stream Restoration Program includes guidelines and development standards for one regional trail and one optional local trail. The EBRPD is interested in accepting a 30 foot easement for a regional trail along one side of Tassajara Creek. The EBRPD would maintain this trail to its standards. The maintenance of this regional 3 PAGF5 OF-- trail could be funded through the EBRPD's two-county landscaping and lighting assessment district for regional trail maintenance. The EBRPD also expressed a willingness to explore a cooperative agreement with the City for ownership,maintenance and operation of the open space within the Tassajara Creek corridor,excluding the Creek itself,which should be the responsibility of Zone 7. They may be interested in owning and maintaining not only the 30 foot trail easement,but the flood plain terrace area between the creek and the 30 foot easement. The EBRPD has certain requirements for assuming such responsibilities. Regulatory Compliance All Eastern Dublin Specific Plan development applicants need to comply with federal,state and local environmental regulations. Applicants should demonstrate consultation with regulatory agencies and compliance with environmental permits. Impacts to wetlands may require federal,state and/or local permits or agreements. Prior to the issuance of grading permits that may impact potential onsite wetlands,permits/agreements may be required from the following regulatory agencies: U.S.Army Corps of Engineers Clean Water Act Permit California Department of Fish and Game Consultation/Agreement State Water Quality Control Board Certification or Waiver Tassajara Creek Lower Reach Implementation Plan for Ownership/Maintenance/Operation The agencies responsible for owning and maintaining certain sections of the Tassajara Creek corridor,between the 1-580 Freeway and Gleason Drive,are depicted on pages 6 and 7 of the staff report. Staff has met with the various agencies,including Alameda County(Lower Reach property owner),that will have some form of maintenance,ownership and operation responsibilities for Tassajara Creek. All agencies,including Alameda County,concur with the implementation plan,Exhibit C. The City will be responsible for maintaining the local trail/maintenance road,30'structure setback and the optional trail landscaping on the west side of the creek and the optional landscaping on the east side of the creek,between 1-580 and Gleason Drive. The City will also be responsible for maintaining the optional landscaping within the stream corridor,between the 1-580 Freeway and Dublin Boulevard. Zone 7 is interested in owning the whole creek corridor,between 1-580 and Gleason Drive,which includes the 30'minimum structure setbacks on both sides of the creek. They will maintain the creek corridor for flood control and water conservation purposes only,and will maintain the maintenance roads between the 1-580 Freeway and Dublin Boulevard. At this time,EBRPD concurs with maintaining and operating the regional trail/maintenance road and the 30'structure setback on the east side of the creek,between 1-580 and Gleason Road. The EBRPD's possible ownership,maintenance and operation responsibilities for the middle and upper reaches of the creek will be determined at some future date. Creek Ownership and Management Responsibilities for the Middle and Upper Reaches The Stream Restoration Program recommends that a public agency should consistently own all 3 reaches within the stream open space corridor. Management of the middle and upper reaches may be the joint responsibility of the EBRPD for maintenance and management of the regional trail;Zone 7 for maintenance of the flood plain terrace and creek channel in specified reaches;and the City of Dublin for the local trail and areas not maintained by Zone 7 or the EBRPD. The City is still in the process of determining all creek ownership and management responsibilities for the middle and upper reaches. 4 FACE ._�i._...,._._` Applicability of Stream Restoration Program Chapter 6 of the Stream Restoration Program includes resource protection,restoration and mitigation guidelines for plants and wildlife. This is a very comprehensive chapter outlining methods and guidelines for plant and wildlife habitat enhancement and restoration that project applicants can utilize while preparing a creek restoration plan. Restoration will be required for all portions of the creek,regardless of channel modifications for flood control purposes. The only exception would be the reaches of Tassajara Creek where existing and native vegetation is abundant and diverse. In these areas,little to no planting is anticipated. However,in this situation,the City will probably require some native vegetation enhancement,consistent with the Specific Plan Policy 6-11 that requires all stream corridors within the Eastern Dublin area to be revegetated with native plant species to enhance their natural appearance and improve habitat values. The revegetation guidelines shall especially apply where creek channel grading modifications create large bare soil areas or remove large stands of vegetation. Where major grading and modifications are proposed to accommodate flood control and access along Tassajara Creek between Gleason Road and 1-580 Freeway,restoration plantings shall be required to provide stabilization and wildlife habitat,subject to the California Department of Fish and Game review and approval. In summary,for the lower reach of Tassajara Creek,restoration plantings will be required and the City will be applying the Stream Restoration Program guidelines and criteria. For the middle reach,the City will determine the level of plant restoration and hydrological improvements required. Optional landscape(non-restoration)plantings could be permitted within the floodplain terrace/100'minimum wildlife setback,and outside the 100'minimum wildlife setback. However,this landscaping will not count towards any creek restoration or enhancement requirements. Due to potentially high establishment and maintenance costs,such landscape improvements will only be allowed with City Council's approval. For the upper reach,the City will determine the level of the Stream Restoration Program's applicability after reviewing the detailed hydrological studies and the applicant's restoration plan submittal. 1 andowner/Public Agency Comments The draft Stream Restoration Program incorporates changes reflective of applicable land owner and public agency comments received during the public review period. CONCLUSION Staff recommends that the Planning Commission recommend City Council approval of the Eastern Dublin Comprehensive Stream Restoration Program,as specified in the Draft Resolution,Exhibit B. The document satisfies the requirements of the Eastern Dublin General Plan Amendment/Specific Plan and EIR. ATTACHMENTS: Exhibit A: Eastern Dublin Comprehensive Stream Restoration Program Exhibit B: Resolution Recommending City Council Approval of Exhibit A Exhibit C: Tassajara Creek Lower Reach Implementation Plan for Ownership/Maintenance/Operation Background Attachments: Attachment 1: Related Eastern Dublin Specific Plan Action Program 6F and EIR Mitigation Measure 3.7/12 Attachment 2: Comprehensive Stream Restoration Program Summary g:\eastdubl\stream\pcsr\crc 5 PAGE S OF__ TASSAJARA CREEK LOWER REACH IMPLEMENTATION PLAN Optional landscape plantings / Required Optional landscape plantings restoration plantings 'Landscape Structure Structure Landscape easement fzi setback I Flood control channel Flood control channel setback easement (20' mini mini (0100) '� 0 F (0100) (30 min) (20' min) 0 0 Existing `�On 0 top of bank -- 1 Excavate for flood Existing grade control channel 1 T ki /77/,/�� _rl;tit_- 1 ) ( '' /\,. //// i 4 7. / / / ._,,TLL 1_--_ Maintenance road / 27/� 3;1 tYP. Maintenance road Meandering low flow channel Wildlife setback* Wildlife setback• - - ----------- (100' min.) I (100' min.) / •(--- Stream Corridor width varies •Measured fromexisting top of bank TYPICAL CROSS SECTION LOWER REACH SUBREACH 1 - '580 TO DUBLIN NTS Tassajara Creek Fig. 3a Ownership Flood Control Maintenance Establishment Maintenance Establishment Ultimate Maintenance & Operation of Required of Required of Optional Maintenance Restoration Restoration/ Landscape of Optional Plantings Optional Plantings Landscape Landscape Plantings Plantings (± 3 - 5 years) A Zone 7 Zone 7 Zone 7 N/A N/A County City - LLD B Zone 7 Zone 7 Zone 7 County County County N/A C Zone 7 Zone 7 Zone 7 County County N/A N/A D Zone 7 Zone 7 Zone 7 County County County N/A E Zone 7 Zone 7 Zone 7 N/A N/A County City - LLD TASSAJARA CREEK LOWER REACH IMPLEMENTATION PLAN Optional landscape plantings Required / Optional landscape plantings 'restoration plantings Structure Structure setback setback (30' min) I Flood plain terrace f / Flood plain terrace I (30' min) /_ Trail/roa Trail/road right-of-wa © A right-of-way Of1Excavate for Top of bank 0 flood plain terrace as required Excavate for flood plain 15 year level terrace as required N. Existing grade _i,, - Regional trail/ maintenance road Local trail/ see fig. 9 maintenance road see fig. 10 Existing grade Wildlife setback• Wildlife setback• (100' min.) I i (100' min.) Stream Corridor width varies Measured from existing fop of bank TYPICAL CROSS SECTION LOWER REACH SUBREACH 2 - DUBLIN TO GLEASON NTS Tassajara Creek Fig. 3b Ownership Flood Control Maintenance Establishment Maintenance Establishment Ultimate Maintenance & Operation of Required of Required of Optional Maintenance Restoration Restoration/ Landscape of Optional • Plantings Optional Plantings Landscape 'NJ Landscape Plantings Plantings (± 3 - 5 years) A Zone 7 Zone 7 City - LLD N/A N/A County City - LLD B Zone 7 Zone 7 Zone 7 County County County N/A C Zone 7 Zone 7 Zone 7 County County N/A N/A D Zone 7 Zone 7 Zone 7 County County County N/A E Zone 7 Zone 7 EBRPD N/A N/A EBRPD EBRPD EASTERN DUBLIN COMPREHENSIVE STREAM RESTORATION PROGRAM SYCAMORE ASSOCIATES BALANCE HYDROLOGICS dk ASSOCIATES JUNE 1996 i. cyri"00„0, I . . . tell( . \ 1 4.0 i - +A , A, SF<< ' I f / l 's _ 5-- ,-, iir ,v.t. ?--,54,,, ..„,,,. ,--- -r. _______ A , , _________,____ \,._ _____________ ,___ EXI :jTk TABLE OF CONTENTS 1.0 INTRODUCTION 1 2.0 RESTORATION GOALS 3 3.0 OPPORTUNITIES AND CONSTRAINTS-OF THE SPECIFIC PLAN AREA 3.1 Hydrology,Hydraulics and Water Quality 10 3.1.1 Flood Hazard 10 3.1.2 Runoff Water Quality 11 3.1.3 Channel Stability and Erosivity,Setbacks 11 3.1.4 Reclaimed Water 11 3.2 Planning 11 3.2.1 Proposed Land Uses 11 3.2.2 Agency Requirements 12 3.3 Resource Protection,Restoration and Mitigation 14 3.3.1 Existing Biotic Resources 14 3.3.2 Resource Protection,Restoration and Mitigation 15 3.3.3 Biological Corridors 15 3.3.4 Invasive Exotic Plants 16 3.3.5 Specimen Trees 16 3.3.6 Soils 17 3.3.7 Project Scheduling and Phasing 17 3.4 Three Reaches 17 3.4.1 Lower Reach 17 3.4.2 Middle Reach 19 3.4.3 Upper Reach 20 4.0 RESTORATION GUIDELINES:HYDROLOGY,HYDRAULICS AND WATER QUALITY 4.1 Introduction 21 4.2 Reducing Flood Hazard 21 4.3 Runoff Water Quality 23 4.4 Soil and Groundwater Quality 24 4.5 Erosion Reduction 24 4.6 Channel Stability and Erosivity,Setbacks 24 4.7 Reclaimed Water 28 4.8 Hydrology and Hydraulics Reference Bibliography 29 5.0 RESTORATION GUIDELINES:PLANNING 5.1 Channel Cross Section and Stream Setbacks 33 5.2 Trails and Maintenance Roads 39 5.2.1 Regional Trail/Maintenance Road Standard 40 5.2.2 Local Trail/Maintenance Road Standard 48 5.2.3 Gravel Maintenance Road Standard 49 5.2.4 Trail Standards by Reach of Tassajara Creek 49 5.2.5 Staging Areas and Trail Heads for Hiking and Equestrian Trails 50 5.3 Stream Crossings 51 5.4 Development Corridor Interface 52 5.5 Channel Modifications and Stabilization 57 • PAGE OF..W- 6.0 RESTORATION GUIDELINES:RESOURCE PROTECTION,RESTORATION AND MITIGATION 6.1 Creek Setbacks and Buffer Configuration 59 6.2 Tributaries to Tassajara Creek 60 6.3 Creek Channel and Bank Modifications 60 6.4 Engineering and Bioengineering Techniques 61 6.5 Protection of Specimen Trees 68 6.6 Protection of Sensitive Resources 69 6.7 Identify Opportunities to Integrate Mitigation into the Creek Restoration Program 70 6.8 Project Scheduling,Construction Restrictions and Coordination Requirements 72 6.9 Lighting in Habitat Areas 73 6.10 Treatment of Transitions to Off-site Open Space 75 6.11 Landscaping of Trails and Adjacent Development 75 6.12 Interpretation 76 6.13 Installation of Bird Nest Boxes 76 6.14 Restoration Treatment of the Three Reaches 80 6.15 Exotics Plant Eradication 82 6.16 Debris Removal 84 6.17 Soils Testing and Treatment 84 6.18 Restoration Plant Palette 86 6.19 Groundwater Testing and Planting Zones 86 6.20 Planting Under Oaks 88 6.21 Container Sizes and Plant Spacing 90 6.22 Plant and Seed Procurement 92 6.23 Mycorrhizal Fungi 92 6.24 Storage and Handling of Seed and Plants 93 6.25 Commercial Sources of Plant and Seed Materials 93 6.26 Genetics Conservation Guidelines 95 6.27 Techniques of Local Cutting Collections 96 6.28 Techniques of Local Seed Collections 110 6.29 Container Planting Techniques 110 6.30 Seeding Techniques 112 6.31 Transplanting Techniques 113 6.32 Areas Expected to Naturally Revegetate 114 6.33 Plant Protection 114 6.34 Temporary Irrigation System 115 6.35 Salvage and Placement of Woody Debris 116 6.36 Horticultural Monitoring and Establishment Maintenance 116 6.37 Habitat Monitoring 120 6.38 Wildlife Surveys 121 6.39 Long-Term Management of Habitat 121 7.0 IMPLEMENTATION 7.1 Implementation and Management 123 7.2 Regulatory Compliance 124 7.2.1 Army Corps of Engineers 124 7.2.2 California Department of Fish and Game 126 7.2.3 State Historic Preservation Office 127 .7.2.4 Stat:^Water Quality Control Board Certification 127 7.2.5 Regional Water Quality Control Board 128 F;,r_ ._c .....� TABLES AND FIGURES Table 1. Recommended Plant Palette 98-101 Table 2. Growth Habits of Plant Species Recommended for Restoration 102-104 Table 3. Recommended Species For Planting Under Oaks 105 Table 4. Plant Availability and Schedule of Local Collections 106-108 Table 5. Recommended Prohibited Species 109 Table 6. Monitoring Schedule 122 Figure 1. Hypothetical Example of Setbacks 27 Figure 2. Corridor Plan Area 34 Figure 3a. Typical Cross Section Lower Reach Subreach 1 1-580 to Dublin 35 Figure 3b. Typical Cross Section Lower Reach Subreach 2 Dublin to Gleason 36 Figure 4. Typical Cross Section Middle Reach 37 Figure 5. Typical Cross Section Upper Reach 38 Figure 6. Plan View Concept Lower Reach 42 Figure 7. Plan View Concept Middle Reach 43 Figure 8. Plan View Concept Upper Reach 44 Figure 9. Regional Trail/Maintenance Road 45 Figure 10. Local Trail/Maintenance Road 46 Figure 11. Local Trail 47 Figure 12. Residential Development Interface 54 Figure 13. Commercial Development Interface with Stream Corridor 55 Figure 14. Residential Development Interface with Stream Corridor 56 Figure 15. Grading Back Slope and Planting 63 Figure 16. Toe of Slope Retrofitted with Rip-Rap and Planted 64 Figure 17. Rip-Rap with Planting Pocket 65 - Figure 18. Terraced Banks for Slope Stabilization 66 Figure 19. Terraced Banks for Slope Stabilization 67 Figure 20. Lighting 74 Figure 21. Sample Nest Boxes 78 Figure 22. Sample Nest Box Building Plan 79 Figure 23. Planting Zones 89 Figure 24. Planting Detail 91 APPENDIX Appendix A Revegetation Schedule Appendix B Special Submittal Requirements EASTERN DUBLIN COMPREHENSIVE STREAM RESTORATION PROGRAM 1.0 INTRODUCTION This Comprehensive Stream Restoration Program has been prepared as required by the Eastern Dublin Specific Plan.Restoration goals contained herein are based on policies and programs in the Specific Plan document and on hydrological,biological,and planning principles. Opportunities and constraints analyzed in this document are based on considerable research, meetings with various agencies and consultations with interested parties.The restoration guidelines are organized by hydrology,planning and biological issues.Implementation, regulatory compliance and long-term management issues are also discussed. The City of Dublin shall enforce the Eastern Dublin Comprehensive Stream Restoration Program policies and guidelines for all Eastern Dublin rezoning and tentative map applications.Appendix B of this document outlines the rezone and tentative map application submittal requirements for stream corridor restoration.Through these submittal requirements,the applicants shall demonstrate compliance with the stream restoration guidelines. Issues discussed in this report include channel cross sections,flood control capacity and maintenance requirements,regional and local trails in conjunction with maintenance roads, habitat protection and restoration,landscaping,recreation,long-term maintenance and management and the interface between the Tassajara Creek corridor and adjacent development. The authors collaborated with the City of Dublin,East Bay Regional Park District,County of Alameda Public Works,Zone 7 of the Alameda County Flood Control and Water Conservation District(Zone 7),California Department of Fish and Game,landowner representatives,Natural Resources Conservation Service and East Bay Municipal Utilities District. The goals of the stream restoration program range from protection and enhancement of wildlife habitat to flood control management and public access.Restoration goals address the inherent limitations of the creek and flood control channel,and focus on separating and buffering wildlife habitat from incompatible human activities.Regional wildlife,including birds,reptiles,amphibians, mammals,and aquatic species use Tassajara Creek and its tributaries for nesting,food,cover, breeding and dispersal of young.Wildlife will continue to use Tassajara Creek and its tributaries if these open space connections are maintained.Restoration efforts focus on wildlife enhancement, while locating development and trails away from habitat areas.The stream corridor cross section required for flood conveyance will provide an adequate setback from the Tassajara Creek channel, and a concentration of wildlife usage is anticipated in this area.To further reduce impacts to available habitat,trails can be combined with maintenance access roads.While limited in the extent 1 of habitat available for wildlife,the urban environment does provide opportunities to improve the stream corridor and link the natural environment with adjacent development through trails. • The historically dynamic nature of the riparian system has been altered and affected by human influences. Previously,rivers and creeks meandered,animals migrated great distances,and vegetation mosaics changed continually.Riparian corridors depend upon periodic flooding,erosion and sedimentation to create the conditions necessary for natural regeneration.The relatively short • lived riparian species require scour to eliminate senescent vegetation and regenerate.Exposed to periodic flooding disturbance,many species have evolved breeding systems dependent upon floods for clearing old vegetation,making new sites available for establishment,amending the soil with nutrient-rich silt and organic matter,and facilitating seed dispersal.Protection and enhancement of the stream corridor will be accomplished by preserving the natural processes of the Tassajara Creek system. The biologist Douglas H.Chadwick eloquently described the importance of design in preserving the full range of evolutionary processes when he wrote: "We cannot tuck species away in little preserves as if we were storing pieces in a museum, then come back a century later and expect to find them all still there. The essence of life is change. Organisms are constantly growing, interacting, adapting, evolving. Their numbers and distribution across the landscape fluctuate in cycles linked to climatic patterns and to other, less understood rhythms. They are defined as much by their place in food webs and nutrient flows as by their own physical traits or any current geographic location. Many alter their range and behavior under different conditions. Some assume entirely new behaviors through learning. In short, an ecosystem is not a collection of plants and animals. It is a seamless swirl of communities and processes. If you don't save the processes,you won't save the parts. So if you're going to create a preserve,you had better make it a big one." With a clear vision of its restoration goals,the City of Dublin can embark upon the restoration planning process.Use of this restoration program will ensure the protection of the natural processes of Tassajara Creek. 2 RESTORATION GOALS 2.0 RESTORATION PROGRAM GOALS The project restoration goals described below are based on the policies and programs of the Eastern Dublin Specific Plan,and biological,planning and hydrologic principles.Policies and programs from the Specific Plan that relate to these goals are noted below in italics. Program-6F: The City should work with Zone 7 and the Department of Fish and Game to develop a comprehensive stream corridor restoration program that identifies a detailed set of criteria for grading,stabilization and revegetation of planning area stream channels. The program would provide guidelines for plant species,planting densities,and long-term maintenance requirements and responsibilities. Such a program will facilitate development approval and insure a consistent standard for stream channel improvement throughout the planning area. The program should identifr the procedures to be followed by applicants for development,permits to be obtained,and improvement and revegetation practices to be implemented. The program should be reviewed by East Bay Regional Parks District. Stream Setbacks Setbacks from the Tassajara Creek channel and the flood plain terrace for structures and trail construction will be established,providing for the protection and enhancement of biological resources,flood control and channel migration.These setbacks will be consistent with the regulatory requirements of the appropriate flood control and regulatory agencies. Program 6G: The City should require dedication of land and improvements (i.e., trails, revegetation, etc.) along both sides of stream corridors as a condition of subdivision approval. The width of dedicated corridors will be established in consultation with the regulatory authority since these may vary with specific sites. Development Interface . Development adjacent to the stream corridor,including the Tassajara Creek channel and the flood plain terrace,should be sited and designed to provide for:protection of riparian habitat and wildlife movement in Tassajara Creek and its major tributaries;regional flood control and maintenance access;regional trail connections accessing schools,parks,neighborhoods,parking and commercial centers;and trail siting and landscaping consistent with trail user safety and police patrols.Conscientious development should incorporate:an emphasis on single loaded streets or cul-de-sac streets that open to the Tassajara Creek corridor;frequent access to trails from adjacent development to encourage trail use as a local pedestrian transit corridor; combining trails with maintenance access roads;placing stream crossings where existing 3 crossings occur or where new crossings would not result in adverse impacts to sensitive biological resources;and compatible landscaping treatments of trails and adjacent development. Treatment of adjacent development and trails should be designed to provide for public safety, especially in the middle and upper reaches of Tassajara Creek and its tributaries where steep banks present a potential public safety hazard. Policy 6-14:Enhance public enjoyment and visibility of stream corridors by avoiding,or minimizing,development that backs • directly onto the stream corridor,and ensure safe public access to stream corridors by providing frequent access points within each development area. Trail Access and Connections Trails within the stream corridor should be sited and constructed to minimize impacts to riparian vegetation and wildlife in the Tassajara Creek channel,and should be integrated with existing and anticipated creek crossings.Trails should be located outside of anticipated flood and sediment deposition areas if feasible,to minimize on-going maintenance.Trail siting, landscaping,lighting,and interpretative signing in the stream corridor should be appropriately designed to minimize impacts to native wildlife,and should provide view corridors as well as a transition to adjacent development and other trails. Policy 4-23: Require all employment-related development to provide convenient and attractive pedestrian, bicycle, and transit- related facilities to encourage alternate modes of commuting to and from work Policy 5-15: Provide a north-south trail along Tassajara Creep and trails along other stream corridors as shown on the • Pedestrian and Bicycle System map. -- Policy 6-3: Provide convenient access from developed areas to designated open space areas and trails. Emphasize pedestrian connections between developed and natural areas. Policy 6-13: Establish a stream corridor system which provides multi purpose open space corridors capable of accommodating wildlife and pedestrian circulation.In order to facilitate the use of these corridors by both humans and wildlife, human activities (e.g.,trails)should be limited to one side of the stream. Maintenance Access Maintenance roads should be designed where appropriate to meet flood control inspection/patrol and access requirements and where possible,should be combined with trails.This will reduce the need for more frequent road maintenance,protect habitat in the Tassajara Creek channel,and provide for public safety and police patrols.Low flow crossings or ramp access should be provided for maintenance;where an actual need is demonstrated.Access to the maintenance roads should be designed to discourage unauthorized use.Single loaded streets along the creek corridor may serve as maintenance roads for visual inspection by flood control staff. Policy 6-12:...Flood control maintenance practices will be designed and performed to be responsive to public safety while preserving-the unique riparian community.Maintenance agreements(memoranda of understanding)between the City and responsible agencies will address,but not be limited to,site access,criteria for determining the need for maintenance(i.e., assessment and monitoring),and the timing and frequency of actual maintenance practices. Habitat Restoration Habitat restoration of the stream corridor should be concentrated in the Tassajara Creek channel where planting requirements,groundwater availability,wildlife use,and the hydrologic regime dictate that such restoration occurs.Restoration should be accomplished through the use of plant species native to the region that are adapted to local soil and microsite conditions,and capable of becoming self-sustaining over the long-term.Restoration should emphasize prompt revegetation of disturbed areas and should prohibit the use of invasive exotic species.Restoration plans should be developed and implemented by professional revegetation specialists.Restoration plantings should be emphasized in reaches of the creek and its tributaries in the following situations:1)sites that are currently support very little native vegetation,or after grading,will have large bare soil areas; 2)areas that require stabilization that native vegetation can provide; 3)locales dominated by invasive exotics that should be eradicated,or lack sufficient native plant diversity;and 4)areas used for habitat mitigation. Policy 6-11:All stream corridors,as shown in Figure 6.2,shall be revegetated with native plant species to enhance their natural appearance and improve habitat values. Revegetation must be implemented by a professional revegetation specialist. Policy 6-22: All areas of disturbance should be revegetated as quickly as possible to prevent erosion. Native trees (preferably those species already on site), shrubs, herbs, and grasses should be used for revegetation of areas to remain as natural open space. The introduction of non-native plant species should be avoided. Specimen Tree Protection Flood control construction within the stream corridor and riparian restoration within the Tassajara Creek channel should protect any existing native vegetation,including any native trees, where feasible. Policy 6-21: Direct disturbance or removal of trees or native vegetation cover should be minimized and should be restricted to those areas actually designated for the construction of improvements. Wildlife Enhancement Wildlife enhancement should be accomplished through restoration of riparian habitat in the Tassajara Creek channel,adequate setbacks from structures and trails,and design provisions to allow wildlife movement through the Tassajara Creek corridor.Wildlife using the Tassajara Creek corridor will benefit from both habitat enhancement of disturbed areas and habitat mitigation,where new habitats are created from upland areas.Restoration should emphasize use of a diversity of native species and habitat structure known to occur in local riparian wildlife habitats,replacement of exotic plants with native plants,and the creation of setbacks or buffers between riparian habitat in the creek channel and public access and structures.Bird habitat can be enhanced by planting native trees and shrubs along the trail right-of-ways and in adjacent development,especially parks. Policy 6-10:Riparian and wetland areas shall be incorporated into greenbelt and open space areas as a means of preserving their hydrologic and habitat value. Unavoidable loss of riparian habitat due to development should be replaced with similar habitat on a 3:1 inkind basis.Loss of wetlands must be mitigated consistent with the ACOE's current policy. Biological Corridor Connections The value of the stream corridor for regional wildlife will be maintained as habitat restoration proceeds and development occurs within the Eastern Dublin Specific Plan Area.Tassajara Creek functions as a major regional wildlife corridor,providing uninterrupted connections to Hidden Valley,Mt.Diablo,Morgan Territory,and Camp Parks,Black Diamond Mines and Contra Loma Regional Parks,among other open space areas.Tassajara Creek should be buffered by stream corridor setbacks established by flood control requirements and consistent with biological criteria.Biological corridor connections from Tassajara Creek to open space within the Specific Plan Area should be provided through the major tributaries draining to Tassajara Creek,and should be protected by restoration and setbacks from structures.Where the wildlife connections along Tassajara Creek or its tributaries would be impeded by road crossings or other development,wildlife underpasses should be provided to mitigate impacts. Policy 6-1: Establish a continuous open space network that integrates large natural open space areas, stream corridors, and developed parks and recreation areas. Policy 6-2: Locate development so that large, continuous open space areas/corridors are preserved. Avoid creating open space islands.Encourage single loaded streets in areas adjacent to open space,rural residential,and agricultural lands. 6 • • Policy 6-18:Development in the planning area will be designed to maintain contiguous areas of natural open space interconnected by functional wildlife corridors, that permit the free movement of wildlife throughout the open space areas.As a means of preserving wildlife corridors, cluster development is generally preferable to an even low-density sprawl over an entire area. Policy 6,19: Where roadways divide open space areas, underpasses or other means of access shall be provided to facilitate the movement of wildlife without barriers. Fencing Within Stream Corridor Fencing within the stream corridor should be designed to restrict trail access by non-maintenance vehicles,and discourage vandalism and undesired pedestrian or vehicular entry into unsafe or sensitive wildlife habitat areas.Fencing should not restrict or impair wildlife movement within the stream corridor and its tributaries or between the corridor and adjacent open space areas. Fencing may be used to funnel wildlife movement into safe passage and away from roads or other hazards. Accommodate Mitigation Within Corridor Owners should be allowed to provide for mitigation in the stream corridor for in-kind impacts elsewhere within the Eastern Dublin Specific Planning Area.The area supporting high value habitat including northern riparian forest,arroyo willow riparian woodland,and freshwater marsh within the Tassajara Creek channel can be expanded as consistent with local site conditions. The Specific Plan's Policy 6-15 states that development of high value habitat including northern riparian forest, arroyo willow riparian woodland and freshwater marsh should be avoided and Policy 6-16, states that these high-value habitat areas should be dedicated as public open space or restricted from potentially harmful development with deed restrictions and design standards. Flood Hazard The design and implementation of the flood control channel within the stream corridor should account for storm water conveyance and sediment loads,channel crossing,maintenance access, and the natural scour and meandering of Tassajara Creek and its tributaries.The configuration of the stream corridor cross-section should allow for the protection,establishment and maintenance of native plant.communities in the Tassajara Creek channel.Except where energy dissipators or bioengineering treatments occur,the creek bottom should consist of natural materials. Policy 6-12: Maintain natural open stream channels to carry storm runoff wherever feasible, rather than replacing with underground storm drainage systems...use retention basins rather FACE LT_c .. ,.. than channelization, if channelization is necessary, design so riparian vegetation can be established. Policy 9-7: Require drainage facilities that will minimize any increased potential for erosion or flooding. Policy 9-8: Require channel improvements consisting of natural creek bottoms and side slopes with natural vegetation where possible fa-meet Policy 9-7. Channel Stability and Erosivity Tassajara Creek channel and bank modifications should accommodate projected flood flows and stream meandering,should employ bioengineering alternatives where appropriate,support native riparian communities and result in a stream channel that has a natural appearance.Where appropriate,the Tassajara Creek channel may be left to naturally meander within a setback designed to accommodate long-term channel changes. Program 61:The City should negotiate with Zone 7 the level of flood control improvements required to meet district standards and rights-of-way requirements and maintenance responsibilities. Water Quality of Runoff and Groundwater The quality of groundwater and urban runoff into Tassajara Creek and its tributaries should meet Best Management Practices(BMPs)and other standards as described in section 9.3.2 of the Eastern Dublin Specific Plan.Water quality impacts associated with cattle should be reduced as cattle are grazed and watered at alternate sources outside the stream channel,as described in the City of Dublin's Grazing Management Plan.Riparian habitat enhancement and restoration,as well as landscaping in the development interface,should stabilize surface sediments. Program 9A:...Require all developments to meet the BMPs of the MOU Regarding Urban Water Conservation in California,of which DSRSD is a signatory. - Policy 9-9:Plan facilities and select management practices in the Eastern Dublin Specific Plan area that protect and enhance water quality. Reclaimed Water The use of reclaimed water to irrigate restoration plantings or trail landscaping should not impair water quality standards. Program 9B:...Implementation of DSRSD and Zone 7 findings and recommendations on uses of reclaimed water to augment existing water supplies. 8 . n • Regulatory Compliance. Development in the Eastern Dublin Specific Planning Area,and restoration in Tassajara Creek, its tributaries or other jurisdictional areas should proceed in full compliance with the regulations and policies of all regulatory agencies with oversight responsibility in this area,including California Department of Fish and Game,Army Corps of Engineers,United States Fish and Wildlife Service,and the Regional Water Quality Control Board.No net loss of wetlands should be allowed. Policy 6-9: Natural stream corridors,ponds, springs, seeps, and wetland areas, as shown in Figure 6.2, shall be preserved wherever possible.Prior to submittal of development applications, the appropriate agencies such as the California Department of Fish and Game and the Army Corps of Engineers must be consulted to determine whether they have jurisdiction over the watercourse or wetland area. Policy 6-10:...Loss of wetlands must be mitigated consistent with the Army Corps of Engineer's current policy. Program 6K: The City of Dublin shall establish and maintain a • liaison with resource management agencies(i.e., CDFG, USFWS, ACOE)for the purpose of monitoring compliance with specific plan policies. These agencies should be consulted and involved throughout the planning and development process of individual properties in order to avoid violations of state and federal regulations and ensure that specific issues and concerns are recognized and addressed. • 9 t OPPORTUNITIES AND CONSTRAINTS 3.0 OPPORTUNITIES AND CONSTRAINTS OF THE SPECIFIC PLAN AREA The rich resources of the Specific Plan study area offer unique opportunities for restoration of the stream corridor,flood control planning for the watershed,and regional planning integrating urban and natural environments.Comprehensively addressing these issues will also pose some constraints to planning in the eastern Dublin Specific Plan area. Restoration treatments in the Tassajara Creek corridor and its tributaries will be constrained by existing conditions and the modifications required by Zone 7 to accommodate 100 year storm flows.Restoration opportunities will vary between the three reaches of Tassajara Creek and the tributaries,as a function of current conditions,project goals and proposed modifications.The three reaches have been defined as:lower reach(Highway 580 to Gleason Road),middle reach (Gleason Road up to and including the East Bay Regional Park District staging area),and upper reach(East Bay Regional Park District staging area to the County line).Restoration opportunities in each of these reaches will be defined by the necessary setbacks from existing or created stream corridor,the extent of grading and channel modification required for flood control or the lack thereof,surrounding land uses,the extent of existing native vegetation and wildlife habitat,the distance to the water table,and trails and maintenance road placement.The opportunities and constraints presented by the Tassajara Creek stream corridor are discussed in this report, subdivided into sections addressing hydrologic resources,planning and biological resources. This is followed by discussion of each of the three reaches. 3.1 Opportunities and Constraints:Hydrology,Hydraulics and Water Quality 3.1.1 Flood Hazard Protection of lands adjacent to Tassajara Creek from flooding is a part of any development planning.A detailed hydraulic study,i.e.,a HEC-2 analysis,which estimates the flood flow conveyance capacity of the channel,has been conducted for the lower reach below Gleason Road by County of Alameda consultants.In this reach,preliminary approval has been obtained from Zone 7 for a plan to expand or reconstruct the creek channel including the removal of a drop structure just downstream of Highway 580.In the middle and upper reaches,above Gleason Road to the County line,HEC-2 modeling still remains to be done.If existing capacity is inadequate,alternatives to be considered include:channel alterations such as broadening, deepening,or smoothing the channel,building levees to protect low-lying areas,and constructing bypasses including surface channels and pipes. Zone 7 of the Alameda County Flood Control and Water Conservation District is the agency which may review and approve any hydraulic studies of Tassajara Creek.However,the City of Dublin may contract with others to evaluate Tassajara Creek hydraulics for channel which will not be under the ultimate control of Zone 7. 3.1.2 Runoff Water Quality In order to ensure good quality runoff water from developed areas,including the Specific Plan Area,the Regional Water Quality Control Board and related agencies have promulgated a suite of recommended measures to be incorporated as needed in each large project.In addition to protecting water quality,these Best Management Practices help protect the aquatic habitat.The City of Dublin_Department of Public Works permitting process requires that these measures, which include erosion control among many others,be planned in detail and implemented for both periods of construction and as a permanent part of any development. 3.1.3 Channel Stability and Erosivity.Setbacks Natural channels erode and migrate.Typically this is a slow long-term,but relentless,process. But it can be sudden.One may envision the area affected as being a corridor the width of the widest part of the overall channel plus a substantial setback for sinuous meandering channels which typically move laterally,braided streams which are subject to evulsions(i.e.rapid unpredictable abandonment of a channel segment and creation of another some distance away), and banks which may collapse.Channel alterations,including grading,vegetation removal,and changes in the hydrologic regime due to development,can alter these natural processes. Provisions need to be made for the movement of meanders,evulsive channels,erosion and stabilization of banks,and control of channel deepening,known as downcutting.Much of this is accomplished through appropriate setbacks.The desirable setbacks for hydrologic purposes and improved property protection may coincide fairly closely with wildlife and other structural setbacks or be larger.This is discussed more fully in the guidelines section below.Thus the protected stream corridor,as mandated by the Specific Plan,is likely to become a valuable multi- purpose amenity to the community,based on a consistent set of setbacks which serve several planning purposes. 3.1.4 Reclaimed Water There is an option for consideration of the use of reclaimed water for irrigation in the Tassajara Creek corridor and on its watershed lands.Supplies of reclaimed water may be readily available from the Dublin San Ramon Services District.Although the use of reclaimed water is encouraged by the state,various technical matters are currently in review related to the protection of groundwater quality in Livermore Valley.Zone 7 is the lead local agency which will provide input on constraints applicable to the use of reclaimed water. 3.2 Opportunities and Constraints:Planning 3.2.1 Proposed Land Uses The Specific Plan proposes a variety of uses along the three reaches of Tassajara Creek.The Specific Plan locates a number of destinations and uses near the stream corridor into which important trail connections need to tie made to ensure the desired level of pedestrian and bicycle circulation.The policies of the Specific Plan encourage the establishment of a continuous open space network that integrates large natural open space areas,stream corridors,and developed parks and recreational areas.The stream corridor runs the entire north/south length of the plan area on the western edge.This stream corridor offers a tremendous opportunity for trail and open space connections linking schools,parks,commercial centers,and other open space areas. Pedestrian access to this corridor can be emphasized by encouraging streets that open up on the creek or are single loaded against the creek,giving the neighborhoods a highly valued character, and providing convenient access to open space and trail connections of the stream corridor. Numerous Specific Plan policies address planning for the stream corridor and adjacent development,resulting in both opportunities and constraints. 3.2.2 Agency Requirements As required in the Specific Plan,meetings were held with staff members of East Bay Regional Park District(EBRPD),Zone 7,California Department of Fish and Game,and the City of Dublin to determine requirements that would constrain construction of adjacent development,trails, roads and maintenance facilities within the Tassajara Creek corridor.The City of Dublin's Parks and Recreation Master Plan also provided direction for the City requirements discussed below. East Bay Regional Park District Through meetings and correspondence,East Bay Regional Park District has expressed interest in having a regional trail,limited to one side of the creek only,as part of the Fact Bay Regional Park District trail system,extending from Dublin Boulevard to the County line.This trail should provide a trail connection from the East Dublin BART/Iron Horse trail to Tassajara Creek along the north side of Dublin Boulevard.Provisions for a potential trail connection under Highway 580 to Pleasanton through County property should be made. Fact/west trail connections to Tassajara Creek should be planned for,as shown in the Eastern Dublin Specific Plan.Plans for local access points to the trail and significant destinations or land uses should be made.The trail should be multi-use,accommodating bikes,pedestrians and equestrians.To accommodate all these uses,the paved trail should be ten feet wide with two adjoining unpaved-shoulders,with one of shoulders to be four to six feet wide,and the other two feet wide,covered with decomposed granite.The City's higher standard of a twelve foot paved trail is acceptable to the District. The multi-use trail would transition to the existing unpaved trail at East Bay Regional Park District's Tassajara Creek staging area.East Bay Regional Park District has requested that the trail to be located above the flood plain terrace to facilitate emergency vehicle access and patrols, provide for public safety,minimize wildlife disturbance and reduce maintenance requirements following flood events.East Bay Regional Park District typically maintains their non-irrigated naturalized vegetation adjacent to trails within their jurisdiction by mowing,and therefore recommends against plantings that have the potential to grow onto the trail and shoulder,require irrigation and cultural treatments,impair visibility or movement,or interfere with their ability to mow. 12 East Bay Regional Park District requires provision for a single primary staging area.It is assumed that the existing staging area will provide needed equestrian access and other staging needs.In the upper reach of Tassajara Creek where the banks are steep and high,East Bay Regional Park District will want to discourage access to the creek banks to minimize impacts to riparian habitat while providing for public safety.Planning treatments in this reach should consider:locating the trail at the outside of the established setback,redirecting drainage above the creek banks,strategically placed fencing, proper signage,removal of large debris or rubble, reducing cattle,watering in the creek,and localized repairs of soil sinking(piping). East Bay Regional Park District recommends that streets be limited to a single-loaded street plan adjacent to the creek.Options for combining Zone 7 access roads with the trail to reduce the need for multiple roads next to the creek should be explored.The creek should be maintained in as natural state as possible to protect and enhance wildlife corridor values.Major road crossings should be designed to accommodate trails.Furthermore,traffic analysis should be conducted to determine appropriate mechanisms for at grade trail crossings to ensure public safety.Traffic improvements could include:stripped crossings,flashing yellow lights and fully signalized crossings. Zone 7 Zone 7 is interested in taking ownership of the lower and middle reaches if their flood control mandate is met(i.e.,100 year flood flows with one foot of additional elevation,know as freeboard)and their maintenance requirements are satisfied.Their maintenance requirements include:continuous access on both sides of creek with an all-weather maintenance road.The maintenance road must be a minimum of 15 feet wide with a four inch compacted aggregate base,and an additional two and one-half feet of clearance on either side of the 15 foot road.They require a minimum 20 foot structure setback from the flood control channel(QI00),but prefer 30 feet,and where controlled access for maintenance is feasible from adjacent parking areas or single loaded streets,the road may be interrupted.Both roads should be above the Q100 within the structure setback.If this is not practical,Zone 7 may accept one road closer to the creek channel,above the Q15.If a lower road is provided,it should be concrete paved or asphalt concrete.Access must be controlled and maintenance ramps to the low flow channel may be necessary at certain locations. Zone 7 has some Special Drainage Area(SDA)funding to take ownership of a portion of the lower reach,from Highway 580 to Gleason Road,insofar as SDA funding is available.Current SDA 7-1 funding is provided for the Highway 580 to 3,000 feet northward,and the program will be reassessed in 1996,which may extend the program to cover a larger area.Zone 7 reviewed the site conditions of the upper reach and concluded that the severely eroded steep banks and other site conditions preclude their ownership.Zone 7 is a strong candidate to own the lower and middle reaches,should funding become available.Should Zone 7 acquire the lower and middle reaches,these reaches may be subject to a routine standing joint use agreement which allows them to release liability and open their facilities to the public for park and recreation use.Thus the City of Dublin could manage the lower and middle reaches of Tassajara Creek as open space 13 • accessible to the public although Zone 7 would own the land.Combining trails with maintenance roads is acceptable to Zone 7. City of Dublin The City of Dublin is interested in having East Bay Regional Park District and Zone 7 take ownership and management of portions of the stream corridor.In general,the City wants trails to accommodate more than one type of trail use,construct trails designed to require as little maintenance as possible over time,and to avoid steep inclines. The trail along Tassajara Creek should be designed to serve as a"Class I Bikeway",providing for bicycle travel on a right-of-way completely separated from any street or highway.Trail standards are described in the City of Dublin Parks and Recreation Master Plan.Given the combined bicycle and pedestrian uses along the trail,the width of the trail should be at least 12 feet.City Public Works recommends that a cleared two-foot wide shoulder on both sides of the trail.The easement for the trail should be a minimum 25 feet wide along major streets or parkways and a minimum of 30 feetwide where private property abuts on both sides.When crossing an arterial street,the crossing should occur where motorists can be expected to stop. Traffic signs for bicyclists should be installed.CalTrans standards should be used for signage and speed controls. California Department of Fish and Game The Eastern Dublin Specific Plan specifies that the California Department of Fish and Game be involved in the development of the Comprehensive Stream Restoration Program.The Department's standards for development includes a minimum 100 foot setback from the top of the bank of Tassajara Creek to protect biological and hydrological resources,unless an exceptionis negotiated with the Department.California Department of Fish and Game provided comments during the CEQA process for the Eastern Dublin Specific Plan area.The Department should be expected to review and comment on all future plan submittals to the City of Dublin,for properties adjacent to the Tassajara Creek,its tributaries,other wetlands and other sensitive habitats,as well as sensitive plant and wildlife- species. 3.3 Constraints and Opportunities:Resource Protection,Restoration and Mitigation 3.3.1 Existi g Biotic Resources Existing biotic conditions are fully described in section 3.7 of the EIR for the Specific Plan and biological resources studies conducted by H.T.Harvey and Associates between 1990 and 1993 for the Dublin Ranch owned by the Lin family.Although most of the plan area is dominated by non-native grassland and dry fanning cropland,there are sensitive resources,the protection of which will impose constraints to development.The EIR includes text discussions and maps noting the locations of red-legged frog populations,an active golden eagle nest,other raptor nests,western pond turtle populations,alkali grasslands,wetlands,springs,seeps and ponds, riparian and other sensitive habitats.This stream restoration program focuses on protection and enhancement of these resources to benefit local and regional wildlife,and enhance their value to the area's residents. 3.3.2 Resource Protection.Restoration and Mitigation Sensitive biological resources such as the red-legged frog and western pond turtle populations, golden eagle nest,raptor nest,wetlands,riparian and aquatic habitats should be protected during the course of development in the Specific Plan area.Impacts to these sensitive resources will have to be mitigated,with the regulatory agencies.The implementation guidelines section on regulatory compliance covers the procedures and agency requirements in detail.The agencies that will issue permits and/or require mitigation will include California Department of Fish and Game,Army Corps of Engineers,and Regional Water Quality Control Board.The Army Corps of Engineers will require permits to"fill"wetlands or waters of the U.S.The Department of Fish and Game will require a 1601-3 Streambed Alteration Agreement and mitigation of impacts for stream crossings.The Regional Water Quality Control Board will enforce its"no net loss of wetlands"policy,requiring mitigation and acquisition of a certification or waiver for Army Corps of Engineers permitting.Impacts to sensitive habitats including wetlands,and waters of the U.S.will require at least 1:1 replacement,while tree removals will require replacement at 2:1, 3:1 or higher ratios,depending on the type of trees and habitat in which the removed trees were located. 3.3.3 Biological Corridors Development around and adjacent to Tassajara Creek and its tributaries will be constrained to protect the value of the riparian corridor as a regionally significant wildlife movement corridor, which provides uninterrupted connections to Hidden Valley,open space areas in Tassajara Valley,Mt.Diablo State Park,Morgan Territory,Camp Parks,Black Diamond Mines and Contra Loma Regional Parks,and other open space areas.Development constraints to protect the value of the riparian corridor for wildlife movement include:1)a minimum wildlife setback on each side of Tassajara Creek,and along minor and major tributaries;2)the construction of wildlife underpasses at'road crossings on Tassajara and its tributaries;3)restoration plantings in the riparian corridors;and 4)landscaping to provide functional and aesthetic transitions along the biological corridor,trails and adjacent development. Protection and enhancement of the biological corridor presents opportunities to maintain the functional value of the riparian areas for wildlife,and preserving habitat for resident and migratory wildlife species that make this area unique.In addition,opportunities arise for bird watching,interpretation,other passive recreational uses,and the integration of natural elements in an urbanizing setting. 15 - C- • 3.3.4 Invasive Exotic Plants The presence of extensive stands of invasive exotic plants both in and adjacent to the Specific Plan area provide an extensive seed bank that will affect future restoration and enhancement plantings.Exotics are known to compete for water,space and nutrients,often resulting in monocultural stands that have little to no benefit to wildlife.Non-native annual grasses are an exception and should be tolerated in this system,since the grasslands do provide wildlife habitat and conversion to native grasses in this region is infeasible.The presence of noxious weeds will necessitate extensive eradication work.Without well-planned and consistently implemented exotics eradication,restoration plantings will have limited success as they will be overtopped by aggressive exotics.To minimize the impact of exotics on restoration and enhancement plantings, landscaping along the trail and elsewhere adjacent to the wildlife corridor will be limited to those plants listed in the plant palette and plants compatible with native oaks.Plants that would be likely to invade the riparian corridor should not be planted in restored or landscaped areas because of their propensity to spread,and a list of commonly used plants that should not be used in this area are listed in the restoration guidelines.Landscaping along trails will provide opportunities to extend the upland habitat and create a transition between adjacent development and the Tassajara Creek corridor. Dense stands of exotics within the Tassajara Creek corridor also present an opportunity to reclaim these areas to native species that will provide improved wildlife habitat and aesthetic character. 3.3.5 Specimen Trees All three reaches of Tassajara Creek support numerous mature native specimen trees,including live oak,valley oak,bay,buckeye,cottonwood,boxelder and more.Great effort should be made during the design and construction of the flood plain terrace,roads and trails and other flood control improvements to protect these trees,and ensure that they will continue to thrive in the future.Decisions regarding which trees have to be removed for flood control and road/trail construction should be made on an individual basis,with 3:1 replacement for all riparian trees (willow,cottonwood and alder)regardless of diameter at breast height(DBH).Other species should be replaced at a 3:1 ratio for individual trees greater than six inches DBH.Non-native tree species,such as eucalyptus,tree-of-heaven and black locust should be replaced with native trees at the 3:1 ratio,since native birds are known to nest in these exotics trees. 3.3.6 Soils Based on the vegetative indicators present throughout much of the Tassajara Creek corridor,soils appear to be very compatible with riparian plantings.An exception to this generalization are alkaline soils characterized by the presence of remnant alkali grasslands in the northeast portion of the plan area.In these areas,restoration and enhancement plantings should be limited to those species that can tolerate alkaline soils;-such as native saltgrass. Elsewhere,native riparian vegetation is found in varying densities in creekside locations throughout the plan area.The density of riparian vegetation does not appear to be related to soils, as much as grazing,recent grading and the prevalence of summer water in the channel.Until soils testing is conducted however,the presence of soils-related constraints cannot be ruled out. The presence of soils that presently support native riparian vegetation appear to present excellent opportunities for enhancing native habitat through restoration plantings.The existence of alkaline soils should be viewed as an opportunity to enhance these naturally occurring communities, rather than as obstacles to riparian plantings that are not adapted to this type of soil. 3.3.7 Project Scheduling and Phasing Implementation of the restoration plantings and flood control improvements discussed in this document will occur over an extended period of time,with activity focused on different portions of the project area over time.Because activities along the Tassajara Creek corridor and tributaries will be phased,coordination between project proponents to ensure implementation of all relevant portions of this plan will be needed. 3.4 Opportunities and Constraints of the Three Reaches Restoration treatments in the Tassajara Creek corridor and its tributaries will be constrained by existing conditions and the modifications required for flood conveyance.Three reaches(Figure 2),spanning 16,100 linear feet have been defined as:the lower reach(Highway 580 to Gleason Road),the middle reach(Gleason Road up to and including the East Bay Regional Park District staging area),and the upper reach(East Bay Regional Park District staging area to the County line).The exiting conditions and the intended channel modifications of Tassajara Creek vary greatly among the three defined reaches,and therefore require consideration and analysis appropriate to the particular reach. 3.4.1 Lower Reach Zone 7 proposes to acquire the corridor from Highway 580 extending northward 3,000 feet. Additional funding may allow Zone 7 to acquire a longer corridor.The lower reach owned by the County of Alameda,was further divided into two subreaches:Subreach 1 extending from I-580 to Dublin and Subreach 2 extending from Dublin to Gleason(Figures 3a and 3b).A proposed plan for the lower reach includes removal of the 70 inch-high drop structure at Highway 580.In Subreach 1 the County of Alameda is proposing creation of a trapezoidal channel,a meandering low flow channel,two maintenance roads above the Q100 on either side of the channel,100-foot setbacks from the existing top of bank,restoration plantings below the Q 15,and landscape plantings above the Q15. Additional landscape easements outside the Q100 will be maintained by adjacent commercial development. In Subreach 2 the County of Alameda is proposing avoiding disturbance to the incised creek channel,creation of a flood plain terrace at the Q15 level on either side of Tassajara Creek to contain 100 year flood flows(Brian Kangas Foulk,1995),a regional trail/maintenance road on the east side of the channel above the Q100,a local trail/maintenance road on the west side of the channel above the Q100,setbacks from the existing top of bank averaging 100 feet,restoration plantings below the Q15,and landscape plantings.Landscape plantings that may require permanent irrigation due to the distance from groundwater table,are proposed in the trail right- of-ways and on the flood plain terrace. Zone 7 has indicated that because of high anticipated flow velocities and unstable soils,bank stabilization may be needed in several locations.Straightening or otherwise increasing the stream's slope would tend to encourage the channel to develop into a fully braided pattern(wide and shallow)which is usually associated with the undercutting of banks and bank retreat, requiring significant protection measures(Dunne and Leopold, 1978,p.626).Although Zone 7 would prefer to spray the riparian vegetation with herbicides to limit the growth of willows,they may not require it.Other design options which may involve different ownership of this reach,but provide the same flood conveyance,are possible.The proposed Brian Kangas Foulk plan generally conforms with these restoration guidelines,provided that the restoration plantings are established below the Q15 and that the 100-foot setbacks are implemented,and Zone 7 flood control and public safety issues are addressed,including the potential evulsive nature of Tassajara Creek. This lower reach will require regrading and modifications to create the flood control channel and flood plain terrace outside the existing channel to carry the higher flows.This reach is also unique because of the surrounding intended land uses.Between Highway 580 and Dublin Boulevard, general commercial is proposed on the west side,and office on the east side of the creek.Above Dublin Boulevard the surrounding intended land uses are characterized by medium and medium- high density residential,an elementary school,a city park to the east,and an industrial park on the west side near Gleason Road.The setbacks along this reach are likely to be controlled by the wildlife and structure setbacks,rather than hydrologic considerations.The development interface along this reach is significantly different than the interface in the middle and upper reaches,where the surrounding land uses will be primarily residential.The regional trail connection from BART is intended to connect to the creek corridor at Dublin Boulevard within this lower reach.All stream corridor crossings should be accommodated by existing or proposed roadways. 18 3� - In the lower reach, plantings over much of the reach will be possible because of the extent of existing disturbance,and modifications required to accommodate flood capacities.The creek channel provides many opportunities for establishment of a diversity of riparian species.The flood plain terrace is expected to support only non-irrigated low maintenance grasses and low- growing perennials because of the distance to the water table.The County of Alameda has proposed to establish landscape trees above the Ql5 on Subreaches 1 and 2;these may require permanent irrigation and are consistent with the restoration guidelines.Efforts to preserve the specimen oaks along the channel will constrain grading procedures.The structure setback will provide opportunities to plant upland tree and shrub species,compatible with the creek environment.Sufficient groundwater may not be available for dense riparian plantings for the entire lower reach because the supply may be lost through sandy substrate into the Livermore- Amador Valley groundwater(David Lunn,Zone 7 personal communication).To some degree this phenomenon may be offset by the increased summer water supply from future upstream development. 3.4.2 Middle Reach Between Gleason Road and the East Bay Regional Park staging area is a 5,000 foot long vegetated channel which appears adequate for 100-year flood conveyance.However,detailed hydraulic analysis,presumably using the HEC-2,will be required by Zone 7.If channel capacity is inadequate,flood conveyance alternatives will need to be considered,such as channel alterations,levees,or bypasses.Zone 7 does not recommend the use of levees in this area. Proposed treatments should transition to the approach adopted in the lower reach by the City of Dublin and Zone 7.As mentioned below in the section on setbacks,additional hydrologic studies are warranted to determine the overall stability of the channel. Compared to the lower reach,the appearance of this reach is more natural,with stream meanders, well-defined channel bed and bank,well-established riparian vegetation,and significant topographic features along the westerly edge.The intended land uses in this reach are- characterized by medium density residential,a junior high school,public/semi public,and the East Bay Regional Park District staging area and a neighborhood park.The residential development interface with the stream corridor should incorporate single loaded streets,cul-de- sacs or loop streets that open onto the stream corridor.Local trails linking the regional trail with the junior high school and the neighboring residential park to the east should be provided. Crossings of the stream corridor should be at the junior high school and the staging area. The middle reach has fewer opportunities than the lower reach for restoration treatments because it is already densely vegetated with native riparian species.Much of this reach probably will accommodate the 100 year flood flows,necessitating less disturbance of the channel.Those sections of the middle reach requiring modifications to create a flood plain terrace will be identified through a detailed hydrological analysis,and depending upon the degree of disturbance to the creek banks,restoration plantings will be indicated.Additional restoration opportunities will exist for those areas cleared of debris and stands of exotics that are eradicated.As in the 19 lower reach, the flood plain terrace will support grasses and perennials,and the structure setback will support upland species. 3.4.3 Upper Reach Tassajara Creek,north from the East Bay Regional Park District staging area to the County line, is a 7,000 foot long channel with a meandering channel form,with locally steep and actively eroding banks.It is a dramatic reach frequently wooded and varied in appearance and often with near-vertical banks over 40 feet high.It is preferable to leave the upper reach as a natural channel with adequate setbacks for structures and public safety,where it can be a valued local resource.Based on field reconnaissance,flood conveyance should be adequate through the channel for most or all of this incised reach.Substantial setbacks seem indicated to protect structures and improvements from bank retreat and channel migration.The setbacks are also relatively greater than in other reaches because the channel is deeper.Alternatively,the applicant may propose to stabilize sections in the upper reach to reduce hydrologic setbacks.Should an engineering alternative be proposed,it should receive close review and comment from the City of Dublin,Zone 7,Army Corps of Engineers and California Department of Fish and Game.An engineering alternative should be reviewed for the potential to trigger a transformation of the creek channel,which may be evulsive(see Section 4.6). This reach contains a channel that is significantly different than either the lower or middle reaches.As mentioned,the channel is very deep and wide with steep banks and it contains some pockets of dense riparian vegetation.The intended land uses in this reach are characterized by medium density residential,single family residential,medium-high residential,neighborhood park,an elementary school to the west and a neighborhood square to the east.The residential development interface with the stream corridor should incorporate single loaded streets,cul-de- sacs or loop streets that open onto the stream corridor.Local trails should be provided that link the elementary school,commercial area,neighborhood square,residential areas and the regional trail.Stream crossings in this reach should be incorporated with proposed roadway crossings. Safety is a concern for users of the trail system along the top of bank and safety should be considered in designing the trail setbacks and treatments. Restoration opportunities in the upper reach will be extensive once grazing pressure on riparian vegetation is reduced.Extensive plantings along the low flow channel will be possible,as well as plantings of riparian and upland species further above the groundwater table.Restoration treatments could extend beyond the current top of bank and could include areas of alkaline grassland.Restoration treatments in the upper reach of Tassajara Creek will be constrained by the presence of cattle before grazing along the creek is phased out.In many areas,vertical banks are inappropriate for plantings. 20F;_: RESTORATION GUIDELINES: HYDROLOGY, HYDRAULICS, AND WATER QUALITY • 4.0 RESTORATION GUIDELINES:HYDROLOGY,HYDRAULICS AND WATER QUALITY 4.1 Introduction Tassajara Creek corridor is a riparian ecosystem consisting of a diversity of habitats and microclimates,and serving a host of eeological,aesthetic,hydraulic,and hydrologic functions. The creek is an avenue for the movement of wildlife as well as the flow of water,the stream corridor being the key regional environment where these elements concentrate and move.The 16,100 foot long Tassajara Creek corridor provides groundwater for riparian plants,aquatic habitat for plants and animals,a means for conveying stream runoff and groundwater seepage through and away from the area,a location for recharging groundwater,an aesthetic amenity,and a spacious open area conducive to human enjoyment. 4.2 Reducing Flood Hazard A key function of the corridor is its ability to contain and convey flood flows up to and including the 100-year design flood.Nearly all storm runoff originates in the upstream portions of the watershed,in Contra Costa County.There is only a small portion of the watershed for Tassajara Creek contained within Alameda County.Since Zone 7 of the Alameda County Flood Control and Water Conservation District is not desirous of any detention facilities(Jack Fong,personal communication),channel conveyance of anticipated flood flows is the prime concern in addressing flood hazard.It is the City of Dublin Public Works Director's understanding that detention facilities may be beneficial if placed upstream in Contra Costa County. Preliminary evaluations by Balance Hydrologics suggest that in the middle and upper reaches of the channel,above Gleason Road,there appears to be adequate channel conveyance for a 100- year flood plus the one foot of required freeboard.In part of the lower reach,between Gleason Road and Dublin Boulevard,there are plans to cut flood plain terraces adjacent to the existing channel to provide 100-year design flow channel conveyance at a rate not to exceed 6 feet-per- second in the constructed area,as specified for earthen channels in Zone 7's Hydrology and Hydraulics Criteria Summary for Western Alameda County. In the lowest reach,below Dublin Boulevard,the channel neerlc to be deepened and widened and/or terraced to accommodate the projected design flow of 5,200 cfs(cubic feet per second)as established by the County of Alameda Public Works Agency(see Appendix 1 in the Santa Rita Drainage Master Plan.)as well as to adjust to the new grade created by the planned removal of the 70 inch-high drop structure south of Highway 580. Of course,additional HEC-2 modeling in the middle and upper reaches and possibly other analyses should be conducted to demonstrate that the design flows can be conveyed in the existing channel.If existing conveyance capacity is inadequate,then alternatives such as broadening,deepening,and smoothing the channel should be considered as well as levees and bypasses.Note that additional studies of channel stability will likely be required.Zone 7 will 21 ✓, determine if flood conveyance is adequate for the channel through each individual property, based on detailed documents to be submitted by the applicant.Zone 7 will evaluate flood conveyance on behalf of the City of Dublin for city areas,as well as evaluate it for reaches which Zone 7 may consider for ownership. In the lower reach between Highway 580 and Gleason Road,the corridor is expected to be owned by Zone 7.Consequently,if this happens,Zone 7's criteria for the acceptance of a property with some possible minor site-specific exceptions will dictate the character and dimensions of the channel as specified in the Alameda County Flood Control and Water Conservation District's Hydrology and Hydraulics Criteria Summary for Western Alameda County.The engineering firm Brian Kangas Foulk has prepared the Santa Rita Drainage Master Plan,including a channel design,and a HEC-2 model which describe the proposed total reworking and enlargement of the flood control channel below Dublin Boulevard(Subreach 1) and cutting of a flood plain terrace to enlarge the conveyance capacity and slow flows between Dublin Boulevard and Gleason Road(Subreach 2).Zone 7 is reviewing these plans and reserves the right to request changes(Zone 7,Memoranda,1995).With the exception of the existing bridge undercrossings,which Zone 7 finds to be already adequate,the channel can be configured as needed to meet conveyance requirements.Future geotechnical work during excavation may expose erodable bank soils which will require stabilization.The existence or likelihood of active downcutting should also be evaluated,particularly in light of the planned removal of the 70 inch drop structure below Highway 580.Weirs or other grade control structures may be needed to limit the downcutting,which tends to destabilize banks and lower the groundwater table.In addition,the constrictive effects of restoration plantings recommended in the guidelines may require a largei channel than previously planned.The guidelines also recommend a minimum 100 foot setback from the top of bank consistent with the Department of Fish and Game standard,unless an exception is negotiated with the Department.Setbacks are also discussed in the restoration guideline sections for planning,and resource protection,restoration and mitigation. Flood conveyance capacity is usually estimated by use of the Army Corps of Engineers'HEC-2 model.It is based upon a series of variably-spaced cross-sections established through a very detailed topographic survey of the channel.The model is especially detailed where there are bends,bridges,channel narrowing,or other elements which tend to constrict or expand the flow, or where there are low banks over which a flood may spill onto adjoining lands. Flood channel capacity,required to be adequate for the 100-year flood flow plus one foot of freeboard according to Zone 7's criteria,can be supplied by leaving the channel as is,enlarging or altering all or part of the channel,defining the extent of the floodplain by building levees, and/or providing a bypass for a portion of the flow.The need for channel alterations is established by initial calculations(usually HEC-2 modeling)and the effects of proposed changes are shown in subsequent model runs.Zone 7 has already called for additional modeling below Gleason Road to examine the impacts of various alternatives proposed by BKF in the Santa Rita 22 -jib( Drainage Master Plan.Above Gleason Road,a new detailed survey and HEC-2 model will be necessary to ascertain other areas where the channel may not fully hold the 100-year design event.For each below-capacity segment,all the alternatives proposed above should be considered.Existing structures may pose some problems in terms of flood hazard alternatives in some reaches. It should also be noted that a regional detention basin for flood control is being planned in Contra Costa County.The proposed facility,if built,will help assimilate flood flows and pulses of sediment emanating from Mt.Diablo,where landslides and wildfires are recurrent(Holmes and Hecht,1992). 4.3 Runoff Water Quality Developed as well as natural lands have an impact on water quality.Storm runoff from streets, buildings,and landscaped areas is contaminated with a host of constituents including oil,grease, nutrients,pesticides,herbicides,heavy metals,sediment,oxygen demanding substances, floatables,and bacteria and viruses.The greatest typical need is to protect the aquatic environment from the acute(short-term)and chronic(longer term)exposures to toxic chemicals. Similarly,the physical character of the water,including attributes such as temperature,dissolved oxygen and the amount of suspended sediments,needs to be protected.The protection of surface waters is mandated through the National Pollutant Discharge Elimination System(NPDES).It involves a permit administered for the Tassajara area by the Regional Water Quality Control Board under the auspices of the Clean Water Act,and the California State Water Resources Control Board. For any development exceeding five acres,a state permit is required from the Regional Water Quality Control Board.The City of Dublin,in turn,will require the state permit prior to issuing approval of grading and improvement plans.However,all developments require approval by the City of Dublin Public Works Department which requires erosion control(ABAG,1980)and the installation of Best Management Practices(BMPs). Measures for combating water pollution from developed area runoff are Best Management Practices.BMPs are detailed in the California Storm Water Best Management Practices Handbooks and Alameda County documents recommended by the City of Dublin.The selection and development of an appropriate suite of BMPs is influenced by land use,terrain,runoff source and volume,development type and extent,capital investment,local preferences by the permitting agency,and other factors.There is a range of alternatives,most of which consist of vegetated areas and ponds,which can concurrently provide an aesthetic amenity and open space to the community.Other BMP measures include:control of the use of and disposal of certain substances,maintenance programs for drainage facilities,public education,recycling programs, landscaping,spill prevention and containment,and dust control. .. -3 23 .,_.. ., Any development should expect to use approved BMPs both during construction and as a permanent part of the development infrastructure.The BMPs are planned in the preparation of the project's Storm Water Pollution Prevention Plan(SWPPP),which must be approved by the City of Dublin prior to the start of construction.Among the requirements established by Ordinance No.52-87,Establishing Requirements for Protection of Watercourses,is that a written permit is required prior to discharging into or connecting any pipe or channel to a watercourse;depositing,planting or removing materials from a watercourse including its banks; altering any structure in a watercourse;and causing flow to be diverted. 4.4 Soil and Groundwater Quality Water quality of groundwater is influenced by local naturally-occurring minerals leached from the substrate.Parts of Tassajara Valley have boron concentrations which are detrimental to growth of most plant species.Other compounds may locally exist in problem concentrations.The Soil Conservation Service's soil survey and Balance Hydrologics'reports(see reference bibliography)include some applicable testing results.Groundwater and/or soils should be tested to ascertain the presence of such chemicals prior to making any investments in restoration planting,as discussed in the restoration guidelines for resource protection,restoration,and mitigation.Zone 7 area(David Lunn,personal communication)and USGS(Glass,1981)have studied local groundwater quality.Findings indicate that groundwater supplies for plantings in the lower reach may be severely limited,due to infiltration to the deep aquifer. • 4.5 Erosion Reduction Development disrupts the soil surface and removes vegetation,exposing the soil to accelerated erosion.Runoff volume and speed is increased and often sent in new directions due to the higher percentage of impervious surface area,removal of vegetation,smoothing of the slopes,and other factors.In an effort to minimize the effects of construction on the aquatic ecosystems and to protect the soil resource,erosion control is mandated as a part of construction permits.Particular efforts are made to provide buffers of undisturbed vegetation adjacent to streams. A construction period erosion control plan(ABAG,1980)is a part of the project's Storm Water Pollution Prevention Plan(SWPPP)submittal to the City of Dublin.It provides for grading to be limited to the dry season and for the protection of some natural vegetative cover.It also requires that sediment traps be installed and maintained to protect watercourses,as well as other BMPs. 4.6 Channel Stability and Erosivity,Setbacks Natural channels and unlined channels constructed in earth are not static;they are intrinsically unstable and dynamic.Tassajara Creek appears to be unusually unstable.A preliminary analysis of the relationship of bankfull discharge(a flow that occurs on the average every 1.5 years)to channel slope for the entire reach of Tassajara Creek,from the County line to Highway 580, indicates that this is an unstable channel.It is a channel apparently in transition with reaches shifting their channel patterns or habit.Based on the limited scientific data available to Balance Hydrologics,it appears to be on the transition between meander and braided forms.This has 7, .�r 24 serious implications for channel stability and definitely needs much more detailed study by a qualified registered professional prior to establishing setbacks or altering the channel form.In particular,any efforts to straighten or otherwise increase the longitudinal slope of the channel may trigger a transformation to a significantly less stable form perhaps leading to evulsive changes.The potential hazard presented by the instability of the stream corridor should not be underestimated.Channel and bank stability improvements should be designed to reduce or eliminate the potential evulsive changes. Streams can incise downward(downcutting),erode their banks(sometimes causing them to collapse into the stream)and move laterally.The materials removed in these processes,be they rock,earth,rubbish,concrete,trash,or vegetation,become a part of the stream and ultimately must be deposited somewhere although they may first disintegrate into fine materials.Much material moves through the creek system incrementally such as from pool to pool,from sand bar to pool,or floats from tree to fence to bridge.Deposits can constrict the streamfiow and thus the local channel conveyance capacity. The Tassajara Creek system is especially noteworthy from the viewpoint of sediment,in that the watershed heads on the slopes of Mt.Diablo,is relatively large in being over 25 square miles, has many areas of active erosion,and consists mostly of steep wildlands which are locally erodable,especially following recurrent wildfires and landslides.Thus sediment and vegetative debris are important in terms of their potential influence on flood channel capacity.However these are particularly episodic processes as indeed are flood flows.These factors are limitations which should be factored into flood control planning but which are not generally analyzed directly.Zone 7 and Alameda County appear to have considered bed sedimentation and`bulking' in selecting a high-end value of 5,200 cfs for the anticipated 100 year design flow. Since stream channels may move either downwards or migrate laterally the corridor width should accommodate such naturally occurring movement.Stabilization is costly and its effects are somewhat unpredictable;often a stabilization measure in one part of the creek will exacerbate problems elsewhere.Such hard structures can also be profoundly unaesthetic.On the other hand, bioengineering or discrete use of boulders and/or vegetative cover can provide the necessary stabilization,or provide an effective camouflage for a hard structure.Bioengineering is described in the restoration guidelines section for resources protection,restoration,and mitigation. Setbacks are a more suitable primary measure to accommodate the relatively low rates of channel migration which prevail regionally.They are an essential means of protecting structures and property.Vertical incision or downcutting is often left to seek its own level of equilibrium,but locally equilibrium can be readily maintained and or managed by the use of weirs or check dams or sandstone outcrops.In areas of constructed channels,such as the lower reach,which may include the removal of the drop structure at Highway 580,measures for channel stabilization, such as have been discussed above,may be required by Zone 7. 25 li' G The City of Dublin requires dedication of land and improvements along both sides of stream corridors as a condition of subdivision approval.Joint use of the stream corridor for recreation and flood control can be compatible,as discussed in Zone 7's Arroyo Management Plan.The minimum setback along open watercourses,which may be enlarged at the discretion of the Director of Public Works,is described in Section 32 of the Ordinance No.52-87 Establishing Requirements for Protection of Watercourses. It specifies that in the case of existing channels where the 100 year design flood can be fully contained,there will be a 20 foot minimum setback beyond the top of bank or,if the bank is steeper than 2:1,it shall be 20 feet beyond the hypothetical top of bank where a 2:1 slope beginning at the bottom of the bank intersects the surface above the top of bank.In this situation,such as frequently occurs in the uppermost reach of Tassajara Creek,where the channel is approximately 50 feet deep,and the bank nearly vertical,the setback would be approximately 120 feet from the top of bank.Figure 1 shows how this looks schematically,in particular in cross-section.In other circumstances,generally not present in the middle and upper reaches,alternative setback criteria are applied as described in the restoration guidelines section on planning and as shown in Figures 3a,3b,4 and 5.Note that in any circumstance,setbacks are required to be outside of designated floodways.Zone 7 has the same minimum setback requirements as the City Ordinance,however has found a wider setback of 30 feet to be more suitable. The minimum setback rules are general rules which likely would be altered where prevailing hydrologic conditions warrant a different approach.The key circumstance on Tassajara Creek is in the upper reach where established looping channel patterns predictably will,over time, migrate downstream,removing the earth which is within the meander loop.In this situation, setbacks from the top of bank will vary in width to accommodate the future movement.A more gentle slope than the 2:1 slope as stated in the City Ordinance No.52-87 is probably appropriate, considering the tendency of meanders to migrate;there is good local precedence for required setbacks to be calculated on the basis of slopes of 2.5:1 or 3:1.Setbacks should be evaluated and determined by a qualified registered professional,taking into consideration all hydrologic issues raised in this document.Geotechnical studies may be a part of such an evaluation.Due to the serious liability related to potentially inadequate setbacks along Tassajara Creek,the City of Dublin should retain their own hydrology consultant to evaluate any hydrologic studies.Figure 1 shows a hypothetical example of the type of a 2:1 setback advisable under such circumstances. However,a much greater setback may be prudent.Under some circumstances,Zone 7 supports using more gentle slopes of 2.5:1 or 3:1.By ascertaining the setback distance from the extreme outlying points of the meanders,stream channel,and top of bank,these points can be connected to define a corridor which probably provides a reasonable hydrologic setback.It should be noted that the topographic maps which Balance Hydrologics had available were inadequate for determining setbacks or other hydrologic uses,however the maps were adequate for the level of analysis required for development of the guidelines.The maps provided to Balance have five foot contours in roughly the northern 60%of the channel,two foot contours in the middle portion,and one foot contours in the southern portion.A much more detailed and accurate map should be developed. 26 � Top of Streambank * . .• 111 Edge of Setback Main Channel IIIII•IIIIII I .``wU�p•` 100 FT -• - .p Fs 1 • 40p ''4/111ftri A /iii, : • *_ • • •• `� A • �����• #0111111111� • 11�11�11���� • • • • • • • • 1 i A A, 50 0- -.N. . • J....-------- - - Feet Setback at 2:1 minimum Cross-Section Showing Hydrologic/Structural Setback at Meander Extreme, thus Establishing a Minimum Limit for the Corridor Setback HYPOTHETICAL EXAMPLE OF SETBACKS NECESSARY_TO ACCOUNT FOR THE FUTURE MIGRATION OF MEANDERS Figure 1 V/ The setbacks will result in different corridor widths for different reaches of Tassajara Creek.If Tassajara Creek is left in its natural state,it is likely that the average width of the Tassajara Creek corridor in the upper reach,from the East Bay Regional Park staging area to the County line,will be 450 to 650 feet since this is the widest,deepest,and probably the most mobile part of the channel.It may even be wider when tributary setbacks are included.In general,the corridor will be widest to the north,toward the County line.Substantial setbacks seem indicated to protect structures and improvements from bank retreat and channel migration.The setbacks are also relatively greater than in other reaches because the channel is deeper. Alternatively,the applicant may propose to stabilize sections in the upper reach to reduce hydrologic setbacks.However,engineering solutions in this reach could trigger the rigorous Army Corps of Engineers'Individual Permit.Should an engineering alternative be proposed,it should receive close review and comment from the City of Dublin,Zone 7,Army Corps of Engineers and California Department of Fish and Game.An engineering alternative should be reviewed for the potential to trigger a transformation of the creek channel,which may be evulsive.An analysis of the creek channel by the applicant's consultant(Harvey and Associates and MacKay and Somps)showed 100 foot setbacks in the upper reach,based on biological not hydrological criteria. In the middle and lower reaches,from the staging area to Highway 580,it is likely that the average corridor width will be 250 to 400 feet,again,probably wider in the upper or northern parts.Further hydrologic studies may show that even wider corridors are needed.Setbacks are also discussed in restoration guidelines sections for planning. • 4.7 Reclaimed Water The use of reclaimed water for irrigation of landscaping or establishing riparian vegetation within the study area would be of regional significance.Although the use of reclaimed water is encouraged as an important part of water pollution control and water conservation through the Clean Water Act and the Porter-Cologne Act,substantial safeguards for public health and the protection of surface and groundwater are in place.In particular,the California Department of Health Services and Regional Water Quality Control Board have established regulations for public health and water quality protection in the event of the use of reclaimed water. The protection is partially administered locally by Zone 7 of the Alameda County Flood Control and Water Conservation District which holds a joint-water-reuse requirements permit(master permit)with Dublin San Ramon Services District and the City of Livermore.In particular,their concern is with the effects of salt loading on the Livermore-Amador Valley aquifer,the Niles Cone Alameda County Water District groundwater basin,local aquifers,and the surface waters. Zone 7 is also responsible for upholding the Regional Water Quality Control Board's nondegradation policy and for avoiding impacts on RWQCB-designated beneficial uses,as set forth in the Basin Plan.The RWQCB is also a necessary contact since they have wide ranging water quality responsibilities.The quality of the reclaimed wastewater to be applied is critical in 28 r _ Cf / • defining restrictions on its use.Supplemental technical studies and monitoring may be required by the agencies to ascertain the likely and actual impacts of the wastewater application on ground and surface waters.However,a major regional study is currently underway by Zone 7,which may obviate this need.In the interim,Zone 7 recommends that irrigation systems should be designed to be easily switched to reclaimed water when such becomes an accepted policy. 4.8 Hydrology and Hydraulics Reference Bibliography-Tassajara Creek,Alameda County ABAG. 1980. Manual of standards for surface runoff control measures. Multipaged. Alameda County Flood Control and Water Conservation District,Revegetation Program. 1983. Revegetation manual. Multipaged. Alameda County Public Works Agency. 1987. Hydrology and hydraulics criteria summary for western Alameda County. 55 pp. Arcement,G.J.;Schneider,V.R. 1989. Guide for selecting Manning's roughness coefficients for natural channels and flood plains. U.S.Geological Survey Water Supply Paper 2339. 38 pp. Barnes,H.H.,Jr. 1967. Roughness characteristics of natural channels.U.S.Geological Survey Water Supply Paper 1849. 213 pp. Brian Kangas Foulk,Consulting Engineers. 1994,October 24. Dublin. Blueprint with map and HEC-2 cross-sections,Tassajara Creek from I-580 to above Gleason Road.Redwood City: Brian Kangas Foulk,Consulting Engineers.. Brian Kangas Foulk,Consulting Engineers. Santa Rita Drainage Master Plan. 1995,October. Redwood City:Brian Kangas Foulk,Consulting Engineers. 89 pp.plus appendices. Brown&Caldwell. 1985,August San Ramon Valley Reclamation Project:primary impact and project report. Prepared for Dublin San Ramon Services District,East Bay Municipal Utility District,City of Pleasanton,and the City of Livermore. 2 volumes. Brown&Caldwell. 1992,May. Livermore-Amador Valley water recycling study. Prepared for Zone 7 of the Alameda County Flood Control and Water Conservation District,Dublin San Ramon Services District,and the City of Livermore. California Department of Water Resources. 1964. Alameda Creek watershed above Niles: chemical quality of surface water,waste discharges,and ground water. 122 pp.plus appendices. = 29 �/ r California Department of Water Resources. 1974. Livermore and Sunol Valleys: evaluation of ground water resources. Sacramento:California Department of Water Resources. Bulletin 118- 2. California Regional Water Quality Control Board-San Francisco Region. 1991. Water quality control plan-San Francisco Bay Region. California Storm-Water Quality Task Force. 1993. California storm-water best management practice handbooks. 3 handbooks plus appendices. CH2MHILL. 1992,January 27. Memorandum:Hydrology and hydraulics for bridge crossing of Tassajara Creek by two-land access road(easterly extension of Dublin Blvd.). Includes HEC- 1 and HEC-2 calculations. Chow,V.T. Open channel hydraulics. City of Dublin. 1987,November. Ordinance No.52-87. An ordinance of the City of Dublin establishing requirements for protection of watercourses. 12 pp. City of Dublin. 1992,September 14(revised). City of Dublin General Plan. Mulitpaged. Dibblee,T.W.,Jr. 1980. Preliminary geologic map of the Livermore quadrangle,Alameda and Contra Costa Counties,California.U.S.Geological Survey Open File Report 80-533. Scale 1:24,000. Dunne,Thomas;Leopold,Luna B. 1978. Water in environmental planning. San Francisco: W.H.Freeman and Company. 818 pp. - EIP Associates. 1992,January 31. Long-range wastewater management plan for the Liver- Amador Valley,draft subsequent environmental impact report. Federal Emergency Management Agency(FEMA). Flood insurance rate map,Alameda County, California(unincorporated areas). Panel 115(revised Feb.19,1986)and panel 120(April 15, 1981). Prepared by Kennedy/Jenks/Chilton. Feth,J.H. 1961. Effects of rainfall and geology on the chemical composition of water in coastal streams of California. U.S.Geological Survey Professional Paper 424-B. Pp.B-202-B-204. Glass,R.L. 1981. Ground-water resources of the Tassajara area,Contra Costa County, California,a reconnaissance report. U.S.Geological Survey Water Resources Investigations Open File Report 81-. 62 pp. 30 • • Holmes,Daniel O.;Hecht,Barry. 1992. Flood hazards and control,alternatives for portions of Tassajara and Alamo Valleys,Contra Costa County. Berkeley:Balance Hydrologics,Inc., project number 9231. Prepared for Tassajara Valley Property Owners Association. Includes HEC-1 and HEC-2 analyses for area immediately upstream of Dublin Specific Plan area. 30 pp. Holmes,Daniel O.;Hecht,Barry. 199-3,June. Tassajara Valley: approaches to hydrologic concerns. Berkeley:Balance Hydrologics,Inc.,project number 9251. Prepared for Tassajara Valley Property Owners Association. 19 pp. Holmes,Daniel O.;Knudsen,Keith;Hecht,Barry. 1993,September. Quality of storm-water runoff in Tassajara and Alamo Creeks,Contra Costa and Alameda Counties,California:1993 baseline report. Berkeley:Balance Hydrologics,Inc.,project number 9251.06. Prepared for Tassajara Valley Property Owners Association. 26 pp. Kent Watson&Associates. 1985. Arroyo Management Plan. San Francisco: Kent Watson& Associates. Prepared for Zone 7,Alameda County Flood Control and Water Conservation District. 23 pp. Leopold,Luna B.;Wolman,M.Gordon;Miller,John P. 1964. Fluvial processes in geomorphology. San Francisco:W.H.Freeman and Company. 522 pp. Pettygrove,G.S.;Davenport,D.C.;Asano,T. 1984. Introduction: California's reclaimed municipal wasterwater resource. This is chapter 1 in Irrigation with reclaimed municipal wastewater-a guidance manual,Pettygrove,G.S.and Asano,T..,editors.Sacramento: California State Water Resources Control Board.Report 84-1. Rantz,S.E. 1974. Mean annual runoff in the San Francisco Bay Region:California 1931-70. U.S.Geological Survey.Field Studies Map MF-613. Soil Conservation Service,U.S.D.A. 1966. Soil Survey,Alameda Area,California. 95 pp.plus plates. U.S.Environmental Protection Agency,Office of Water. 1993. Guidance specifying management measures for sources of nonpoint pollution in coastal waters. Multipaged. U.S.Geological Survey. 1971,November 24. Suggested criteria for hydrologic design of storm- drainage facilities in the San Francisco Bay Region,California. Open File Report. U.S.Geological Survey. 1977,June. Magnitude and frequency of floods in California. WRI 77-21. 31 U.S.Geological Survey. 1915-1930;1979-1983. Tassajara Creek gaging records for stations near I-580. Station numbers 11-1750 and 111763000,respectively. Wallace Roberts&Todd. 1994,January 7. Final Eastern Dublin Specific Plan. Prepared for the City of Dublin Planning Department. San Francisco: Wallace Roberts&Todd. 168 pp.plus appendices. -- Welch,L.E. 1977. Soil survey of Contra Costa County,California. 125 pp.plus plates. White,Chris;Hecht,Barry(CEG);Holmes,Daniel O. 1994,May. Regulatory and resource protection considerations of a proposed treated effluent irrigation program for portions of the Tassajara and Alamo Valleys,Contra Costa County,California. Berkeley: Balance Hydrologics,Inc. Prepared for Tassajara Valley Property Owners Association. 33 pp.plus tables and figures. Unpublished. Woodward-Clyde Consultants. 1991. Alameda County urban runoff clean water program loads assessment summary report. Submitted to Alameda County Flood Control and Water Conservation District. (in association with Kinetic Laboratories Inc.). Zone 7,Alameda County Flood Control and Water Conservation District. 1959. File No.FC 300. Drainage area map. Zone 7,Alameda County Flood Control and Water Conservation District. 1990,March (updated). Flood control base map,Zone 7 owned and maintained facilities. Sheet FN,File No. FC. Scale 1:2,000. Zone 7,Alameda County Flood Control and Water Conservation District. 1991,April. Urban water management plan update for Zone 7 of Alameda County Flood Control and Water Conservation District, Dublin San Ramon Services District,City of Livermore,City of Pleasanton. Zone 7,Alameda County Flood Control and Water Conservation District. 1995,July 20 and September 1. Letters to Brian Kangas Foulk concerning Tassajara Creek improvements,Gleason Road to I-580 Freeway. PP.C.,742 32 RESTORATION GUIDELINES: PLANNING 5.0 RESTORATION GUIDELINES:PLANNING 5.1 Channel Cross Section and Stream Setbacks Three reaches of Tassajara Creek have been identified for planning purposes:lower reach " (Highway 580 to Gleason Road),middle reach(Gleason Road up to and including the East Bay Regional Park District staging area),and upper reach(East Bay Regional Park District staging area to the County line).Figure 2 shows the Tassajara Stream Corridor Plan Area,including the three reaches,proposed land uses,major road crossings,setbacks and the regional trail alignment. The hydrological setbacks are described in detail in hydrology restoration guidelines for channel stability and erosivity,setbacks.Setbacks for tributaries to Tassajara Creek and sensitive habitat features,such as seeps and aquatic sites are discussed in restoration guidelines section for creek setbacks and buffer configuration. The lower reach was divided into two subreaches:Subreach 1 extends from I-580 to Dublin boulevard,and Subreach 2 extends from Dublin Boulevard to Gleason Road.The proposed conceptual cross section for the lower reach(Figures 3a and 3b)establishes three primary zones or treatments within the stream corridor:1)the creek channel(the incised or graded portion of the existing stream corridor that carries lower flows and supports riparian vegetation 2)the flood plain terrace or the flood control channel(the area outside the creek channel and within the Q100),and 3)the structure setback(above the Q100).The combined width of the flood plain terrace and the structure setback should be a minimum of 100 feet on either side of the incised or graded channel to comply with California Department of Fish and Game setback standards, unless an exception is negotiated with the Department.This minimum setback is referred to as the wildlife setback in Figures 1,3a,3b,4 and 5. The proposed conceptual cross section for the middle reach(Figure 4),between Gleason Road up to and including the East Bay Regional Park District staging area establishes three primary zones or treatments within the stream corridor: 1)the existing creek channel that supports riparian vegetation(which in some sections contains the Q100 and in other sections does not), 2)the flood plain terrace(the area of the existing stream corridor above the existing creek channel,or the area graded to accommodate the flood flows below the Q100),and 3)the structure setback (above the Q100).The combined width of the flood plain terrace and the structure setback should be a minimum of 100 feet on either side of the existing channel to comply with California Department of Fish and Game standards,unless an exception is negotiated with the Department. The northerly portions of the middle reach are expected to contain the 100 year flood flows, while the southerly portions may not.A detailed hydrological analysis based on cross sections will confirm existing conditions and will identify requirements to grade the flood plain terrace to accommodate flood flows. ( 33 . �V Ta s s a ara Creek Figure Optional landscape plantings Required O-A Optional landscape plantings II restoration , r, LandscapeLandscape Structure Exis tin g easement Structure setback 0. Flood control channel — creek channel od control channel setback I easement ' 0 I f 11 " j, 1 Ile Maintenanceroad Wildlife setback* low flow channel Stream Corridor W#jIIRR*Q Maintenance road typo Wildlife setback* `100' min., width varies SUBREACH DUBLIN N'rS a -a ra Creek Figure 3a Measured from existing top of bank i 2 • Excavate for flood plain as required--, Existing grade Local traill maintenance road r `00' in., Required restoration Crook channel c a to for raclain 15 year level terra s required 710 Regional traill--'l �I maintenance road Wildlife setback* TYPICAL CROSS SECTION Tassajara Creat Figure 3b lra (100' min.) *Measured from existing top of bank •, R Creekchannel Varies Existing 0 .. of ba j i ;r w Local tranx maintenance ,. • 10 `1 0' fn.) Excavate for . •. plain required(- terrace as MWMMM % egional fraff// maintenance road s® a f®. �- 0773 • • TYPICAL CROSS SECTION MIDDLE REACH Mrs Tassajara Creei Figure 4 `10 /n.) i Hydrologic / Structural Hydrologic/ Structural _ setback setbackvaries variesvaries Regional trail I maintenance road see fig., • Wildlife setback Existing top of bank i i #7Z Tr 1 .11 Sw TYPICAL CROSS SECTION UPPER REACH NTS Tassajai-a Figure Local it see fig. The structure setback, described for the lower and middle reaches, should be a minimum of thirty feet in width along both sides of the creek outside the flood plain terrace. The trails and maintenance access right-of-way should be concentrated within this setback. Wider structure setbacks should be encouraged. Landscaping and vegetation of adjacent developments or within the structure setback should create a soft edge to enhance and enlarge the trails and maintenance corridor. The proposed conceptual cross section for the upper reach (Figure 5), above the East Bay Regional Park District staging area to the County line establishes two primary zones or treatments within the stream corridor: 1) the existing creek channel that readily contains the 100 year flood flows and supports riparian vegetation at lower elevations. and 2) the hydrological - wildlife -structural setback outside the existing creek channel. The hydrological setback incorporates structural and slope bank failure considerations for the character of this portion of the channel. To comply with California Department of Fish and Game standards, the wildlife setback is a minimum of 100 feet from top of the existing channel banks, unless an exception is negotiated with the Department. The wildlife and hydrological setbacks will overlap and the greater of the two controls the final outside edge of the stream corridor. 5.2 Trails and Maintenance Roads Consistent with the Specific Plan, the trails and maintenance roads should be combined and located to establish a stream corridor system that provides multi -purpose open space corridors capable of accommodating both wildlife movement and pedestrian circulation. Trails and maintenance road planning should encourage a continuous open space network that integrates large natural open space areas, the stream corridors, and developed parks and recreation areas. This trail and open space network should then link regional and local trails, employment centers, residential areas, schools, parks, commercial centers, neighborhood parks and open space. The trail system should accommodate pedestrians, bicyclists and equestrians, in addition to the maintenance vehicles. Local trails and local trails/maintenance roads are shown on figures, however under the Specific Plan, the City of Dublin is only required to provide for a regional trail and connections to that trail. Figures 3-5 show typical cross sections and Figures 6-8 show plan view concepts for the lower, middle and upper reaches of Tassajara Creek. Figures 9-11 show the trail standards for the regional trail/maintenance road, local trail/maintenance road and local trail. Tributaries should be improved with local trails designed to connect to the regional trail and provide convenient pedestrian and bicycle connections between neighborhoods and other destinations within the plan area. Local trails should utilize the tributary as an open space corridor connection. Access should be controlled through the use of bollards, gates or similar systems acceptable to the emergency response agencies, to prohibit undesired vehicle access, while allowing maintenance and emergency vehicle access and encouraging bicycle use of the regional trail. Access points should be provided at multiple points, at approximately 1,300 foot intervals along the stream corridor. Conrrolled access for maintenance vehicles should be provided through adjacent development, such as parking areas and residential streets. Where a street parallels the creek corridor, separate access is not necessary. In addition, where a street parallels the creek corridor, the sidewalk may be eliminated in favor of pedestrian and bicycle use of the regional trail. This creates a softer edge of the development against the stream corridor. _'_ 41 - oil Q • n is 1a a a Ito la ' •� �a° •a I a i 1 L� e a t ® •® o® .• do ® ® ••le a • • • 1 • • I , ' • • 3 m '. Y u Y! Y 7 J Y 1 J ® W • ` ' ®��� W b® /C/�� s a, W •w W �' • a U j Q � � L C •C oc V c � e ® e s ®q V V W m 0 .1 ro 5 L —o Q h H _ cc oLo a® �y (A o y Lao z w o o o 0. 1 O2c , 1 � • 0 o z U cn V a Ch 2 uj Q. l� 1471:11tr- • ;=7 ,/7', " 4. j-0///r/////.( //{_z_1_1_7_11f4.% th //1 / y 6" aggregate base (1: Of Q) Regional trail N f f f 12' wide, paved do.4' min 18' wide all-weather surface !, 30' structure setback •, REGIONAL TRAIL/MAINTENANCE ROAD Tassajara Creek Figure 9 s` -r (------------ikti d v$ z 0 IS m ` CC dla CS V R % Z RI .1C h. u z� a W A yto a o I L.) o te E°' �t. I' a, 'f, RI y E C os t ti Q CIa ` m O1 1 J ` 0 N v w Nisi ; 'RIa• a. r.----1 N a w m 0 3 13 3 2 /eAe.16 ,Z �. S. \ • ss' . ' ,,,,_,.. .• s ‘• -w?''' '''-'''',, .. . ,, s . _ ..4,,,,, ii. Is , . .. . ,44. .,, , . ,,,, . , . vil 6" aggregate base kA.kbi _ . __ _ _ � E . ,% \/ Zu N Local trail ` N , 8' wide, paved 12' wide all-weather surface 25' easement / 30' where development occurs both sides LOCAL TRAIL NTS Tassajara Creek Figure 11 5.2.2 Local Trail/Maintenance Road Standard Consistent with the Specific Plan and requirements of East Bay Regional Park District,Zone 7, and the City of Dublin, local trails are required to provide connections between residential neighborhoods and destinations,such as the regional trail access points,employment centers, commercial areas,neighborhood parks,schools and open space.The local trails should be designed to serve pedestrians and bicycles. These guidelines for local trails and roads combine standards from all three agencies,with an emphasis on the stricter City's Trails and Bikeway standards in the City of Dublin Parks and Recreation Master Plan.The local trail should accommodate pedestrians and bicyclists within a twenty five or thirty foot easement,depending upon adjacent land uses.The combination local trail/road should consist of eight feet of paved pathway with six inches of compacted aggregate base,and with two rocked shoulders,two foot on either side of the trail(Figure 11). Where local trails are combined with the maintenance road that is required by Zone 7.This local trail/maintenance road should have the fifteen feet of gravel all-weather surface required by Zone 7 on a six inch compacted aggregate base.Eight feet of this surface shall be paved,leaving seven feet in rocked shoulders.A twenty foot right-of-way should be maintained clear for Zone 7 (Figure 10). • The local trails that run parallel to Tassajara Creek may be interrupted at certain locations as dictated by specific site conditions,however ingress and egress to the trail system should be provided at these points of interruption.Adequate maintenance vehicle access should also be provided at these points. Access to the local trails should be controlled through the use of bollards,gates,fences or similar systems acceptable to the emergency response agencies to prohibit undesired vehicle access, while allowing for maintenance and emergency vehicle access and encouraging bicycle use of the local trails.In situations where a maintenance road will not be used as a local trail,fences may be necessary to control undesired access.Access points should be provided at multiple points,sufficient to link local pedestrians and bicycles to the regional trail and other significant destinations,such as schools,parks,the regional trail and shopping and adjacent land uses such as residential areas.Local trails should provide east/west connections from adjacent land uses and other destinations to the regional trail.Controlled access for maintenance vehicles should be provided through adjacent development,such as parks,parking areas and residential streets at multiple points approximately 1,300 feet apart along the stream corridor.Maintenance access will be facilitated where streets parallel the creek corridor. In addition,where a street parallels the creek corridor,the sidewalk may be eliminated with the local trail serving as its substitute as long as the local trail is sited outside the flood plain terrace or within the structure setback.This will create a softer edge to development against the stream corridor. 48 FL:1211., 5.2.3 Gravel Maintenance Road Standard Where no regional or local trail is proposed,and Zone 7 will require maintenance access,gravel roads on both sides of the creek should be provided as in Subreach 1 in the lower reach(Figure 3a).Zone 7 requires a fifteen foot all-weather surface with a six inch compacted aggregate base, both preferably located above the Q100. If this is not practical,Zone 7 may accept one lower maintenance road above the Q15,paved in asphalt concrete or concrete.Controlled access to the maintenance roads at these locations should be provided through adjacent development,such as parking areas and streets.Ramps to the low flow channel may also be necessary and should be evaluated on a case-by-case basis.Where Zone 7 maintenance roads will not be required,a combination trail/road or trail without road should be provided as discussed above. 5.2.4 Trail Standards by Reach of Tassajara Creek Trail standards should reflect surrounding conditions and needs,and accordingly,have been developed by creek reach. Lower Reach of Tassajara Creek The lower reach of Tassajara Creek is located between Highway 580 and Gleason Road.Consistent with East Bay Regional Park District requirements, the regional trail/maintenance road should be located on the east side,while the local trail/maintenance road should be located on the west side of Tassajara Creek.As expressed by East Bay Regional Park District,the regional trail should be located above the flood plain terrace,within the structure setback,to facilitate vehicle patrols,maximize public safety, minimize wildlife disturbance and reduce trail maintenance requirements following flood events. The regional and local trails could meander within the wildlife setback to create interest. The local trail/road should be located above the flood plain terrace,above the Q100 in this reach. A regional trail connection from the East Dublin BART/Iron Horse trail to Tassajara Creek along the north side of Dublin Boulevard,and a provision for a potential trail connection under 1-580 to Pleasanton through County property should be made. Where trails are not planned in this reach,gravel maintenance roads should be provided on either side of the creek according to Zone 7 maintenance access requirements(Subreach 1).These maintenance roads could at some point in the future be converted to a trail to facilitate the future Pleasanton connection. The regional trail and maintenance road may occasionally meander out of the structure setback and onto the flood plain terrace within the wildlife setback,but should primarily be located in the established right-of-way to maximize public safety,enhance access for police patrols,minimize wildlife disturbance, and minimize trail maintenance due to erosion or siltation. 49 Trail connections across Gleason Road should be made at grade.Trail crossings at Dublin should be made under the Dublin Boulevard bridge,with an alternative route for at grade crossings in wet weather conditions. • Middle Reach of Tassajara Creek In the middle reach of Tassajara Creek,between Gleason Road up to and including the East Bay Regional Park District staging area,the regional trail should connect with the trail on the lower reach at Dublin Boulevard and continue on the eastern side of Tassajara Creek until it reaches the staging area.As with the lower reach,the regional trail should be located within the structure setback above the flood plain terrace.The regional and local trails could meander within the wildlife setback to create interest. The local trail/maintenance road should be located on the west side of the creek,within the flood plain terrace.The maintenance road may be interrupted by existing site constraints.The eucalyptus grove above Gleason Road will prohibit construction of a road.Where the trail is interrupted,controlled maintenance access should be provided with a vehicle turnaround.The local trail however should continue uninterrupted along the stream corridor. The regional trail and maintenance road may occasionally meander out of the structure setback and into the flood plain terrace within the wildlife setback,but should primarily be located in the established right-of-way to maximize public safety,enhance access for police patrols,minimize wildlife disturbance, minimize trail maintenance due to erosion or siltation. Upper Reach of Tassajara Creek In the upper reach,from the East Bay Regional Park District staging area to the County line,the regional trail/maintenance road should cross Tassajara Creek at the staging area,and continue along the western side of the creek in the setback from the top of the Tassajara Creek bank.The local trail from the middle reach merges with the regional trail at the staging area.In the upper reach a local trail should be located on the eastern side of the creek within the setback area.Both the regional and local trails in the upper reach may occur within the wildlife setback.The local trail should cross the tributary channel in conjunction with the proposed street. 5.2.5 Staging Areas and Trail Heads for Hiking and Equestrian Trails The Specific Plan provides a primary staging area in conjunction with a school or a park. Equestrian uses should be compatible with other staging area activities.Equestrian access should continue to be provided at the existing East Bay Regional Park District staging area.The existing regional staging area should be enhanced in accordance with standards for staging areas and trail heads in the City of Dublin Parks and Recreation Master Plan.The primary staging area should accommodate horse trailers,drinking water,rest rooms,telephone,hitching posts,a rest area with tables,access for emergency vehicles,fire hydrants,trash receptacles,lighting,gates, signing and fences.Loading areas for horses should be buffered from Tassajara Road,to create a safe environment for handling horses. 50 Trail access points should be provided at connections to the regional trail throughout the plan area,including park and school locations.Access points should have at a minimum the lesser improvements consisting of parking,drinking water and trash receptacles.Other trail access points along the regional trail should be treated as enhanced trail access points and should receive parking,drinking water,trash receptacles,rest rooms,lighting,and telephone.Drinking water should be provided at frequent intervals along the trail. 5.3 Stream Crossings Creek crossings should be sited so as to provide convenient access to destination areas,such as parks,schools,the commercial center and other open space,and to link the local and regional trails.Creek crossings should be designed and landscaped to emphasize creek character,establish view corridors and screen wildlife from concentrated human use. Where roadway crossings are combined with trail crossings,the trail user should be separated from the traffic by an appropriate barrier for safety considerations,such as raised sidewalks, raised curbs or concrete barriers. There should be a creek‘.rossing approximately every 2,000 feet along the creek corridor to facilitate pedestrian access to the trails.In each of the three reaches of Tassajara Creek,there will be a specified number of road crossings,therefore added pedestrian or road creek crossings will be necessary at certain locations to link the trails with adjacent land uses.Figures 6-8 show existing,proposed and potential stream road crossings at approximately 2,000 foot intervals,in the lower,middle and upper reaches of Tassajara Creek. In the lower reach(Highway 580 to Gleason Road),the two road crossings and the transit spine crossing with associated trail crossings proposed by the County will be adequate with some modifications for public safety to meet this criterion. In the middle reach(Gleason Road up to and including the East Bay Regional Park District staging area)a minimum of two trail crossings should be provided to create crossings at approximately 2,000 foot intervals.This reach is approximately 4,200 linear feet in length.The Specific Plan shows no road crossings to access the medium density residential area on the west side of the creek.A trail crossing should be combined with a road crossing in the middle of this reach to access the medium density residential area on the westerly side of the creek. Alternatively, a trail crossing could be provided at the northerly boundary of the Junior High School site,linking the local trail from the neighborhood park site to the east of Tassajara Road. The East Bay Regional Park District staging area,at the boundary between middle and upper reaches has a pedestrian crossing that should remain.An additional crossing for maintenance and emergency response vehicles should be created in the vicinity of the staging area crossing. 51 The Specific Plan shows five road crossings in the upper reach(East Bay Regional Park District staging area to.the County line), however this many crossings many be infeasible given the width of the Tassajara Creek in this reach.The reach is approximately 5,600 linear feet and a crossing will be provided at the East Bay Regional Park District staging area,therefore a minimum of two well-spaced crossings should be provided to adequately satisfy the trail crossing guidelines.The local trail along the tributary to the east and north of the staging area should be continued in a northerly direction along-the east side of the creek and should share the staging area crossings. There are seasonal crossing that are usable during low flow periods,located along Tassajara Creek,which may serve local unmaintained access needs.These crossings however,do not meet ADA standards,nor do they satisfy the trail and road standards described herein Additionally, they are not usable during moderate creek flows.Therefore they may remain but should not be included in the trails planning.If low flow crossings are removed,restoration of disturbed areas is described in restoration guidelines for resource protection,restoration and mitigation. Creek crossings should not reduce the flood capacity of the creek,but should be designed to provide for continued trail access either above or below the crossing.Special trail sections such as stream crossings are addressed in the City of Dublin's Parks and Recreation Master Plan. Some existing crossings,such as the East Bay Regional Park District crossing,should remain with the understanding that it may wash out in very high flows and would have to be rebuilt. Creek crossings will occur at all major road crossings of Tassajara Creek.Creek crossings should be designed and landscaped to emphasize creek character,establish view corridors and screen wildlife from concentrated human use. Creek crossings should be located to minimize disturbance to the riparian vegetation in the creek corridor,while maximizing engineering stability.Since the meanders of Tassajara Creek will migrate down stream over the long term,crossings should be placed above meanders where feasible,and the very wide portions of the creek should be avoided.The creek section should be stable,which is generally indicated by dense vegetation.Bridge construction should strive to minimize impacts in these sections.The vegetation will also screen the crossing.Bridge design should avoid or minimize piers or other supports in the creek channel since these are known to catch debris in high flood flows.If piers are incorporated into a design,they should be widely spaced to minimize catchment.An appropriate location for a creek crossing would be a narrow and stable or vegetated section of the creek,located above a meander. 5.4 Development-Corridor Interface The interface between proposed development and the stream corridor should be evaluated in great detail.Development abutting the stream corridor should meet several criteria including: 1) preservation and enhancement of the biological values;2)convenient corridor access;3)street 52 layout concepts similar to those presented in Figure 12;4)separation of wildlife and human activities within the corridor;5)provisions for frequent access points within each development; and 6)enhancement of the visibility and character of the stream corridor.The stream corridor constitutes the major north/south open space feature of the Specific Plan area.The character of the stream corridor should be complemented by its interface with proposed adjacent land uses. The interface should vary with adjacent land use. Figures 6-8 show in plan view the potential interface between the stream corridor and adjacent development for the lower,middle and upper reaches of Tassajara Creek.Figure 12 shows three types of road systems to create a desired development stream corridor interface.Figures 13 and 14 show typical stream corridor interfaces with commercial and residential development, respectively. Open space trail alignments should be coordinated with street sidewalks and bike lanes to:ensure continuity of linkages between schools,neighborhoods,and commercial centers;achieve convenient access from developed areas to designated open space areas and trails;and emphasize pedestrian connections between developed and natural areas. Creekside trails should be coordinated with wildlife corridor requirements and planning should avoid development that backs directly onto the stream corridor.Residential development should be designed to•orient to me creek as a visual amenity.Schools and parks should be designed to take advantage of creekside settings and educational opportunities. Trail heads should be provided at the corridor interface with convenient vehicular,bicycle and pedestrian access points,such as schools and parks,and where streets abut the corridor. The structure setback,described for the lower and middle reaches,should be a minimum of thirty feet in width along both sides of the creek outside the flood plain terrace.The trails and maintenance access right-of-way should be concentrated within this setback.The thirty foot structure setback should be widened in places to allow the regional trail to meander to create interest.Landscaping and vegetation of adjacent developments and within the structure setback should create a soft edge to enhance and enlarge the trails and maintenance corridor. 53 In r 'Y SINGLE LOADED STREETS ,,.,-,. -1- F. .r A , , �z� ,-, , NM A a LOOP STREETS tj CUL-DE-SACS ,-r r �- L „_ , x 4_±- :E. ,i, , -- ,/ >,(iko- ,),., -4- RESIDENTIAL DEVELOPMENT INTERFACE NTS Tassajara Creek - J Figure 12 Statogger buildingcreatesofter setbacksedge 0 Trail I 5 o Flood plain terrace If I 0 I Creek channel 0/11 } s .,...oj ( COMMERCIAL DEVELOPMENT INTERFACE WITH STREAM CORRIDOR NTS Tassajara Creek Figure 13 -- _ Eliminate sidewalk �� f into favor of trail 1 ' e softeno edge e e• \ Flood plain .17 ; I , .) terrace ____1___L / i :. --�, , , ii, , , Trail 0 o 1 Creek channel A RESIDENTIAL DEVELOPMENT INTERFACE WITH STREAM CORRIDOR NTS Tassajara Creek 79 Figure 14 In commercial and industrial zones,buildings should be staggered or offset from the creek corridor to enlarge the apparent open space setback and soften the linear edge of the creek corridor(Figure 13).Views from proposed commercial and office facilities as well as outdoor areas associated with these uses should be oriented toward the stream corridor.Screening of trails from parking lots,storage areas,trash receptacles,loading docks,and similar facilities should be accomplished through landscaping. Pedestrian access to this corridor can be emphasized by encouraging streets that open up on the creek or are single loaded against the creek,giving the neighborhoods a highly valued character, and providing convenient access to the open space and trail connections of the creek corridor (Figure 14). • Where the stream corridor abuts neighborhood parks, the stream corridor should be integrated into the park design and use.Active park uses should be limited to the outside of the flood plain terrace,and passive park uses should be allowed to enter the flood plain terrace.Park uses should be prohibited in the creek channel. 5.5 Channel Modifications and Stabilization Channel improvements or modifications should accommodate projected flood flows and extensive revegetation,and avoid the need for periodic vegetation removal,as discussed in the restoration guidelines for hydrology.Preservation of the creek channel,is paramount to the preservation of the existing vegetation and wildlife corridor,consistent with the restoration goals. The channel should be allowed to naturally revegetate,erode and meander within the flood plain terrace.The preferred cross section of creek emphasizes a creek channel that supports vegetation and a flood plain terrace to accommodate stream corridor setbacks and additional flood flows. The flood plain terrace should be managed to support non-irrigated grasses.Landscape plantings could be established on the flood plain terrace with permanent irrigation.Where channel modifications are required,the channel should be shaped and graded to contours with a natural appearance.Figures 3-5 show typical cross sections of the stream corridor for the lower,middle and upper reaches of Tassajara Creek. The landowner,the County of Alameda is proposing removal of the drop structure at Highway 580 and modification of the creek channel and/or flood plain terrace between Highway 580 and Gleason Road to accommodate flood flows.In Subreach 1 a trapezoidal channel is proposed. Modifications in Subreach 2 will be designed to preserve the natural meandering of the existing stream.The reach of stream above the Gleason Road presents an excellent model for meandering in this system. Unless necessary,modifications to the creek channel of Tassajara Creek should be minimized. Any regrading of the creek channel of Tassajara Creek should result in a natural appearance with a gently meandering creek bottom. 57 Any regrading of the creek channel should result in varying side slopes to provide a more natural appearance.Regrading to create a flood plain terrace above the low flow channel should be gently sloped,with a maximum slope of 3:1.The wildlife setback(100 feet from top of existing bank)may allow for a very gentle slope on the flood plain terrace. Non-structural solutions should be used to increase channel capacity and stabilize stream banks. Energy dissipaters and erosion control-devices should consist of natural materials,i.e.,vegetation or boulders,to increase the roughness coefficient of the channel bottom.Energy dissipaters should be adequately engineered to handle peak flow conditions of Tassajara Creek.Detailed hydrological analysis should determine erosive potential of various flood-stage flows.Careful study should be made to ensure the adequacy and stability of any proposed energy dissipaters and bioengineering devices.Bioengineering techniques are discussed in the restoration guidelines section below for hydrology,as well as resource protection,restoration and mitigation. Trails and maintenance access roads should be located to avoid disruption by the meandering of Tassajara Creek.Where the trails and maintenance roads deviate from the outside edge of the stream corridor and are sited on the flood plain terrace,adequate setback from Tassajara Creek should be adopted to protect their long-term integrity. Outfall structures should be designed according to official County drainage improvement standards.Improvements can be made to the outfall design to screen the hard structures from trail and bridge users.Planting in rip-rap and other hard structures is discussed in restoration guidelines for resource protection,restoration and mitigation.Outfall structures and low flow creek crossings that have minimal effect on the channel bottom and low flow channel are desirable.Long-term erosion effects of these features should be considered as well. Disruption to the wildlife corridor should be minimized. • 58 769- RESTORATION GUIDELINES: RESOURCE PROTECTION, RESTORATION AND MITIGATION • 6.0 RESTORATION GUIDELINES:RESOURCE PROTECTION,RESTORATION AND MITIGATION 6.1 Creek Set Backs and Buffer Configuration A setback from the Tassajara Creek channel and its tributaries is required for biological as well as flood control reasons.The hydrological setbacks are described in detail in hydrology restoration guidelines for channel stability and erosivity,setbacks.Regarding biological considerations,the California Department of Fish and Game routinely recommends a 100-foot set back from the top of the existing banks of major creeks,such as Tassajara Creek and its major tributaries,as discussed in the planning restoration guidelines for channel cross section and stream setbacks.Because the riparian zone most valuable to wildlife is within the creek channel,the stream corridor cross section required for flood control will in most cases provide the needed setback from Tassajara Creek. Biological(wildlife)setback requirements for the tributaries vary with the site conditions, environmental,resources,need to accommodate trails and nature of adjacent development.In general,setbacks should be 100 feet from the existing top of bank for major tributaries and 50 feet from top of bank for minor tributaries according to California Department of Fish and Game standards,unless an exception is negotiated with the Department.Setbacks for the minor tributaries for which trails have been planned should be a minimum of 50 feet,with the trail sited primarily at the outside of the buffer.For the purpose of this document,minor tributaries are defined as grassy swales not supporting shrub and tree vegetation,and major tributaries are • defined as tributaries that are deeply incised,and support a dense canopy of shrubs and trees. Applicant submittals should justify proposed tributary setbacks based on:flood flows,existing vegetation,quality of habitat,bank conditions and treatments,and current and proposed land uses.Proposed tributary setbacks should be large enough to ensure public safety,flood control, • restoration plantings and safe passage of wildlife. Biological setback requirements for the major tributaries where deeply incised in the northeastern portion of the study area should be a minimum of 100 feet from top of bank.Setbacks associated with the golden eagle nest within this corridor have been established in the Eastern Dublin General Plan Amendment and Specific Plan Final EIR. Erosion and hydrologic considerations may allow for flexibility in the biological setbacks for tributaries.The buffer created by the setbacks on major tributaries does not need to be centered on the creek,although equal distribution on both sides is preferred in most cases.As long as the hydrologic setback minimum is met,the biological or wildlife setback may be arranged to incorporate more valuable habitat on one side of the tributary at the expense of less valuable habitat on the other.Alternatively,it may be narrower than 100 feet(or 50 feet for minor tributaries)for short stretches,if it is wider in others and its average is the required buffer area.Under no circumstances should the buffer be less than 50 feet on one side.If creek banks are graded back to form gentler slopes or channels are reconfigured,the 50 or 100-foot setback would be calculated from the original top of bank.Before the buffer is modified however,erosion and hydrologic 59 -7 setback requirements must still be met.Newly configured banks should be restored with native vegetation.Bank reconfiguration should be accompanied by specific restoration plans designed to improve overall wildlife values. Setbacks from sensitive habitat areas,such as seeps,and aquatic sites for sensitive amphibian species may require greater buffering and should be evaluated on a case-by-case basis by the City of Dublin,California Department of Fish-and Game and U.S.Fish and Wildlife Service. 6.2 Tributaries to Tassajara Creek There are several tributaries to Tassajara Creek in the Specific Plan Area.In general,all of the restoration guidelines described herein apply to the treatment of the tributaries,with noted exceptions.For the purpose of this document,minor tributaries are defined as grassy swales not supporting shrub and tree vegetation,and major tributaries are defined as tributaries that support shrubs and trees or are in close proximity to ponds,seeps or springs.Setbacks and buffers are discussed in the above section. Many of these tributaries are candidates for restoration,both habitat enhancement and mitigation. Mitigation of sensitive aquatic habitats,such as that for the California red-legged frog and western pond turtle may be more suitable in the tributaries than in Tassajara Creek,since flood flows and sediment loads can thwart amphibian habitat creation. As with Tassajara Creek plantings,the groundwater profile of the drainages must be determined through measurement or interpolated from vegetative indicators,in order to determine planting zones prior to development of planting plans. Engineering or bioengineering in the tributaries may be required to:dissipate energy,reduce flow velocities at or near the streambank surface,buffer the streambank against the abrasive effect of transported materials,induce sediment deposition,and armor banks against high flows and debris. Because flood flows in the tributaries are less severe than in Tassajara Creek,bioengineering techniques may be feasible alternatives to hard engineering structures. Setback requirements for the tributaries vary with the site conditions,environmental resources, the need to accommodate trails,and nature of adjacent development.Setbacks are discussed in the section above entitled Creek Set Backs and Buffer Configuration. 6.3 Creek Channel and Bank Modifications Creek channel and bank modifications are discussed in other sections.On sites where grading modifications create large bare soil areas or result in removal of large stands of vegetation, revegetation according to these guidelines should occur.Where major grading and modifications are proposed to accommodate flood control and access along Tassajara Creek between Gleason Road and Highway 580,restoration plantings should be required to provide channel stabilization and wildlife habitat,subject to California Department of Fish and Game review and approval.In 60 • reaches of Tassajara Creek where existing native vegetation is abundant and diverse and needs no modification,little to no planting is anticipated. 6.4 Engineering and Bioengineering Techniques Bioengineering is a low-tech method of construction using living plants in combination with non- living or inorganic materials.Engineering techniques on the other hand,rely solely on inorganic materials,or hard structures to achieve similar goals.Bioengineering within the stream corridor, where feasible,is desirable because the plants incorporated into the engineering treatments,i.e., bioengineering,serve to camouflage the hard structures,provide additional stabilization and provide habitat value.Bioengineering is used for a number of purposes including:dissipate energy, reduce flow velocities at or near the streambank surface,buffer the streambank against the abrasive effect of transported materials,induce sediment deposition,and armor banks against high flows and debris.In most instances,the living plants become the functioning technical component of the system.There are site conditions that dictate hard structure solutions,but where appropriate, bioengineering alternatives should be considered and be given preference if bioengineering can accomplish the goals.For example,check dams constructed to check downcutting may rely on large rock,concrete structures or secured logs.If logs could create maintenance problems by becoming dislodged in high flows,hard structure solutions should be used.Bioengineering techniques are not necessarily more stable or less expensive than traditional structural engineering solutions. Possible scenarios for which engineering or bioengineering solutions should be considered include: bridge crossings,creek low flow crossings,creek bank stabilization,trails or roads located near stream banks,and check dams.It is critical to analyze and document the upstream and downstream hydrologic conditions and fluvial geomorphic processes affecting the stream system before designing appropriate engineering or bioengineering treatments.Any changes to channel hydraulics caused by the installation of these treatments should be analyzed and documented,for appropriate agency review. Soil compaction during the installation of bioengineering structures is discouraged,because compaction will restrict or preclude the desired plant establishment.If compaction is necessary to stabilize steep slopes or fill material,alternatives to mitigate this barrier to plant establishment should be evaluated by a revegetation specialist.Soil auguring or ripping may be recommended to enable adequate root growth in compacted soil. Figures 15-19 illustrate several alternative bioengineering treatments,including:grading back slope and planting,planted rip-rap at toe of slope,rip-rap with planting pocket,and terraced banks.These figures represent conceptual treatments,and are not considered specifications.Other bioengineering alternatives not illustrated include:sackcrete with mature trees,gabion structures with topsoil, gabion blanket with planting cells or tubes,stepped-front gabion retaining wall with planting holes, post and wire revetment,rail and cable revetment,geoweb cellular confinement system retaining 61 • wall,low toe wall with slope flattening,live staking,live willow posts,contour wattling.contour brush layering,wire reinforced brush mats,brush deflectors,live wooden crib wall,willow wall, anchored tree revetment,and rootwad boulder log revetment. A document prepared by the Habitat Restoration Group entitled "Biotechnical Streambank Stabilization", illustrates many of the bioengineering techniques employed in a wide range of restoration projects. Only species native to the region should be utilized in the bioengineering treatments. Plant palettes for trees, shrubs, and forbs and grasses are provided below. • • 62 11r Grading Back-Slope and Planting Jt ,• 0 41,' 0Existing oversteepened slope '�'' CC New graded slope O Rip rap New vegetation Figure 15 Toe of Slope Stabilized with Rip Rap and Planted • • + ;0400 i h'r I.i ‘1, 41_0 i 4.1.,11 or \ 08 O Install planting collars '� O Install pole cuttings and backfill 4s1••.eum�r with approved topsoil (as approved by © Project Ecologist) OExisting sackcrete-protected bank Figure 16 Rip Rap with Planting Pocket • ` • • • � yr �� �. Shrubs and trees in planting pocket ORip rap may be grouted and shall be carefully placed,not dumped O Planting pockets to be 34-X 34-wide Figure 17 ')i) Terraced Banks for Slope Stabilization 1, s r _ c. .7' 1 ,P 5 ; =.- ...> .D7 , :. -AV "L°.--": . /147 ; .� ,. � i - \c\::.5.'"') High Terrace - v Mid Terrace :47. 4 f 5.3 • tea Low Terrace , Figure 18 Terraced Banks for Slope Stabilization • • • r//,... r it4 i„, lilt '?, ,�, ��,�.�,,{-,,: : 4 � p O O Terrace may be stabilized by rocks,logs,or low vertical walls O High Terrace ® Mid Terrace ® Low Terrace Figure 19 6.5 Protection of Specimen Trees While the City of Dublin does not have a heritage tree ordinance,residents nevertheless have a keen interest in protecting and maintaining native trees,especially oaks.Protection efforts should be focused on the several native upland and riparian species,as well as some mature non-native eucalyptus trees providing nesting habitat,that are found in and near Tassajara Creek and its tributaries.Immature eucalyptus trees-should not be protected and may be removed as part of an exotics eradication program.Mature eucalyptus determine by a qualified biologist to not be providing important wildlife habitat may be removed. Modification of the stream corridor to provide for flood conveyance and maintenance access will in many cases require grading around these trees.Prior to preparing grading plans,all trees equal or greater than 6 inches in DBH(diameter at breast height,or 4.5 feet above the ground)should be accurately mapped. When these native trees or the mature eucalyptus occur within the area to be graded,a qualified arborist should be consulted to determine whether the trees can be saved,and what procedures should be employed.Emphasis should be placed on protecting,where possible,native and mature eucalyptus trees that are equal to or greater that 6 inches DBH.For trees to be protected during construction,a detailed set of tree protection guidelines should be developed,describing: construction fencing,cutting roots in the least damaging manner,preventing the storage of materials and equipment around protected trees,avoiding changes in drainage patterns around trees,cultural treatments,construction monitoring,and other protection measures. Construction monitoring by a qualified arborist should be required during grading near preserved trees,to ensure the implementation of protection measures and to account for additional trees lost during construction,for which mitigation should be provided. To mitigate for the loss of native trees 6 inches in DBH or greater and mature eucalyptus trees that cannot be saved during construction of the flood plain terrace and modifications to the stream banks,three trees for each one removed should be planted and established.This translates to a 3:1 mitigation ratio. Container sizes for mitigation trees should be greater than or equal to citrus pots in size,but may be as large as boxed specimens.Citrus pots are the optimum container because they support a deep root system and moderate top size at planting time;pot size is 8 by 14 inches and volume is four gallons.If all trees are grown in citrus pots,restoration success will be greatly enhanced. Pole cuttings are acceptable for mitigation of willow or cottonwood species.In order to count towards mitigation of removed trees,trees should be planted in the stream corridor ecosystem where they are beneficial to wildlife.Street or landscape trees should not count towards mitigation credits.Mitigation should be with the same tree species as the trees that were 68 removed,unless the trees removed were eucalyptus or other non-natives.Mitigation of non- native tree removals should be with native species.Planting and establishment guidelines are provided in sections below. Monitoring for a duration of five years should be required to ensure establishment of the mitigation trees,with a general site review to occur a minimum of six times during the first year, and twice per year annually thereafter.-A qualified monitor should conduct a quantitative evaluation of the mitigation plantings twice in year one,and annually in years two through five. This quantitative evaluation should measure and evaluate survival and native plant health and vigor.Performance standards should focus on survival and growth.Growth,measured quantitatively in the mitigation trees,should demonstrate a trend towards healthy establishment. Tree survival within five years should be at least 85%in the fifth year.If over 100 mitigation trees are planted,sample plots that will result in statistically representative sampling may be used to reduce monitoring efforts.Monitoring should also trigger remedial actions,such as replacement of mortality,control of exotics, repair erosion,addition or removal of tree cages,cultural treatments, and other measures at the discretion of the monitor.Table 6 shows a schedule for the mitigation monitoring. 6.6 Protection of Sensitive Resources Sensitive resources include seeps,springs,ponds and the golden eagle nest in a tree along a major tributary to Tassajara Creek in the northeastern portion of the Specific Plan Area.It is possible that other sensitive resources will be identified during site analysis and planning of Tassajara Creek and its tributaries.Protection of known and discovered sensitive resources should be described prior to any construction of the flood plain terrace or modifications to the stream banks.The protection of these resources during construction is a high priority.The tree in which the golden eagle nest is located should be protected during and after construction as should any other raptor nests encountered during any construction along the creek or tributaries. Work around these nests should be scheduled to avoid active nesting.A qualified arborist and - wildlife biologist should be consulted to determine the best methods to avoid impacts to the trees with active nests. Springs,seeps or ponds that occur within the Tassajara Creek corridor or tributaries should be protected during grading.The functions and values of the seeps should be maintained,and alterations to subsurface conditions that feed these aquatic features should be avoided.Seeps, springs and ponds can create microclimate conditions that are favorable for wildlife or plant species that have limited distribution elsewhere and are therefore of vital importance to native flora and fauna. Temporary or permanent fencing in habitat areas should be reviewed by a qualified biologist for potential impacts to wildlife movement. 69 Construction fencing of ponds,seeps or springs should not interfere with migration of amphibian species.Silt fences can be placed so as to allow migration at critical time periods during the species life cycle. Any permanent exclusionary fencing in the stream corridor or its tributaries should not present barriers to wildlife.Five-strand barbed wire fences are compatible with wildlife passage and should be used. • -- Construction in the stream corridor should avoid the wet season,generally recognized by the resource agencies to be October 1 through April 15.Both construction and restoration plans and specifications Should include detailed erosion sedimentation control elements. 6.7 Identify Opportunities to Integrate Mitigation into the Creek Restoration Program Restoration is a general term that is often used interchangeably with ecological restoration,habitat enhancement,habitat creation,revegetation,reclamation and management.For the purposes of this document,the term restoration is used in the general sense to include two strategies:habitat enhancement and habitat creation.These restoration strategies are defined as they are generally used by restoration professionals in California and by the Society for Ecological Restoration. Ecological Restoration is the process of intentionally altering a site to establish a defined, indigenous,historic ecosystem. The goal of this process is to emulate the structure,function, diversity and dynamics of the specified ecosystem. Restoration is differentiated from other efforts to establish plants in that the stated goal is to establish plants,animals,plant communities,natural processes,functions and values that are self-sustaining over the long term.Restoration in the Tassajara Creek corridor could involve habitat enhancement or habitat creation(mitigation). Habitat Enhancement is the increase in one or more values of all or a portion of an existing habitat through site alteration and for the improvement of a specific habitat function.Enhancement of a degraded site may include interplanting existing vegetation with indigenous species and removing competitive weed species.If a riparian or wetland site is degraded,its enhancement is not deemed creation or mitigation,because no new habitat results from the enhancement efforts.This is consistent with the"no net wetland loss"policies of the state and federal regulatory agencies. Habitat Creation or mitigation is the conversion of a site to a habitat type that has not existed there in recent times(100-200 years).Created wetland habitats must occur on existing upland sites,and almost always involve lowering the site to the water table appropriate to the target wetland type. Habitat creation in the Tassajara Creek corridor should not be confused with habitat enhancement. Habitat creation may be applied as mitigation credit for impacts elsewhere in the study area. Mitigation or creation that is near the site of impacts and integrated with a larger restoration effort of the stream corridor is consistent with conscientious bioregional planning and should be encouraged. Mitigation of habitat impacts originating within the Specific Plan study area should be encouraged to occur within the Tassajara Creek corridor or its tributaries where feasible.This can be accomplished through habitat creation outside or within the actual channel. Landscaping with natives adjacent to the trails located on or above the flood plain terrace is not considered restoration,since most of the project restoration goals cannot be achieved at these locations.For example,the groundwater table at these locations will most likely be too low, restricting the new landscape's potential to emulate habitat structure,density,diversity,functions and values found in native riparian systems.Additionally, many species of wildlife will not use these landscaped strips because of the frequent exposure to trail users,and permanent irrigation may be necessary to sustain these plantings so removed from the groundwater table.However, these plantings should be compatible with the habitat enhancement located in the channel.Trail landscaping will significantly improve the aesthetics of the site and will serve as a buffer to the actual riparian corridor used by wildlife.Landscaping should use species native to the region and if non-natives are used,these should be non-invasive species that cannot naturalize in the adjacent natural areas. • Habitat impacts anticipated within the project study area that could be mitigated within the stream corridor include:riparian,freshwater marsh,waters of the U.S.,and habitat specifically for sensitive species,such as the California red-legged frog(Rana aurora draytoni)and western pond turtle (Clemmys marmorata).These species are Federal Candidates(List 1)for listing as threatened or endangered,and California species of special concern.If construction is carefully planned,limited impacts will occur with construction of the flood plain terrace,bridge crossings,creek low flow access,creek bank stabilization,check dams,and placement of engineering or bioengineering structures.In most cases the required mitigation can be integrated into the project design,by minimizing impacts,restoring natural contours,and revegetation with appropriate natives. All mitigation proposals will require the review and approval of the regulatory agencies. If habitats for sensitive species are to be created in the Tassajara Creek corridor,grade modifications which result in secondary impacts may be required.Mitigation plans should account for these secondary impacts through avoidance,minimization and compensation. Habitat creation or enhancement plans for sensitive amphibians should account for sedimentation loads and flood flows in the Tassajara Creek system that could interfere with habitat creation efforts.Analyses may show that sedimentation loads and flood flows work at odds with these habitats,and that the tributary drainages to Tassajara Creek are in fact more suitable to amphibian habitat creation.Obviously these habitats occurred historically in creeks with high flows,but mitigation programs that require monitoring and performance standards for specific sites do not have the flexibility to credit the applicant with washed out ponds that will be recreated elsewhere in the creek system. Other issues the mitigation plan should account for include:pre-construction surveys for sensitive amphibians and capture and release if deemed necessary by California Department of Fish and Game and U.S.Fish and Wildlife Service;phasing habitat creation with other creek improvements; fencing from cattle and other site protection;demonstrated appropriate hydrologic regime that can provide for aquatic habitat of the frog and turtle(e.g.water retained in ponds from February until September for red-legged frog);refugia sites to minimize poaching and predation;dispersal corridors and breeding sites appropriate-to the sensitive species;measures to prevent introduction of bullfrogs(Rana catesbeiana)or any fish species,including mosquito fish(Gambusia affinis) as these species are predators on the eggs and larvae of the frog;mosquito abatement measures as alternatives to mosquito fish;design of stand pipe to drain ponds should non-native predators be detected;measures to discourage the dispersal of the frog and turtle into developed areas,such as fencing or ensuring the accessibility of suitable dispersal sites;water quality of run-off and aquatic sites;native plantings to enhance breeding habitat and provide cover;and construction precautions,including fencing during construction that does not interfere with migration of amphibian species. 6.8 Project Scheduling,Construction Restrictions and Coordination Requirements Projects are phased when the project is too large or costly to execute at one time,or when land ownership patterns and project administration imposes the need for phasing.In the case of Tassajara Creek and its tributaries,phasing of restoration activities will likely coincide with construction of the flood plain terrace,and the combined trails and access roads,and/or the development activities of adjacent landowners.Phasing would allow the City of Dublin and landowners to establish coordinated procedures for planning,plan review,permitting, construction,maintenance and monitoring the creek and tributary projects.In the event of phased development along the creek and its tributaries,all projects should adhere to these guidelines to ensure comprehensive treatment of the stream corridors and protection of riparian resources. Project construction should not begin until all required permits have been secured.In the event that construction is phased,permits should be secured for the entire project before construction begins in any area. Construction in the stream corridor should be scheduled to avoid the wet season,generally recognized by the resource agencies to be October 1 through April 15.Construction work should be scheduled to avoid active nesting periods near the golden eagle nest,or any other raptor nests encountered in the project area.A qualified wildlife biologist should be consulted to determine the best methods to avoid impacts to the trees with active nests. Site access and staging areas should be identified and marked for construction and landscape contractors,both on plans and in the field.Specifications should require use of designated staging and access areas to ensure protection of sensitive areas. 72 PAGE.1107 Protection of sensitive areas and activities restricted during construction and installation should be clearly identified on plans and specifications.Flagging or construction fencing may be necessary and should be required if there will be equipment larger than pickup trucks anywhere near the creek or tributaries.Contract sign-off,contract penalties and posting of bonds may be tied to the protection during construction of existing sensitive resources,such as specimen trees, nesting trees or active burrows,seeps,ponds or springs. Final plans and specifications should address contractor and public safety,licensing and qualifications of contractors,dust control,and site cleanup. Construction may disrupt wildlife activities.Removal of vegetation and modification of the channel and creek banks will have the greatest impact.Additional impacts will result from noise,dust and soil compaction.Site modifications should be restricted during active nesting periods of sensitive species.Major site modifications should be scheduled during late summer,when birds have completed nesting. The final plans and specifications should provide specific schedule constraints.Biologically important seasonal windows will govern most restoration activities,such as seed collections, exotic plant eradication at specified times,construction outside of nesting seasons,and planting and seeding prior to rains. The final plans and specifications should be prepared by both revegetation specialists and biologists experienced with biological resource planning and restoration planning and installation.Installation should be overseen by a qualified revegetation specialist. Project scheduling is a complicated task that requires the expertise of professionals with implementation experience and familiar with the project's biological constraints.Conscientiously planned and tightly managed scheduling will permit considerable efficiencies,cost savings and necessary protection of biological resources.The project schedule should be integrated into construction documents and contracts.Appendix 1 provides a structured approach to schedule a restoration project,such as the restoration for Tassajara Creek and its tributaries. 6.9 Lighting in Habitat Areas Trail planning should strive to locate trails away from the habitat areas in the Tassajara Creek channel.Lighting in habitat areas should be avoided wherever possible because lighting has a detrimental effect on certain wildlife species.However,should any trail segments with lighting be situated adjacent to habitat(within 50 feet),low elevation light poles,low intensity street lights and shielding the internal silvering of the globe or use of external opaque reflectors to direct light at the ground should be employed to prevent adverse impacts to wildlife.These details are graphically depicted in Figure 20. 73 Lighting in Habitat Areas (frft 4-9 Low intensity Street Lights © 'fit 0 r h � f li�i frs �z,`c�°' 4=, e : / s f'Ps)� • Low elevation light poles OInterval silvering of globe luminaire OOpaque reflectors to direct light at ground Foot path lighting - - Figure 20 �� 6.10 Treatment of Transitions to Off-site Open Space Landscaping of trails and adjacent development is needed to create functional and aesthetic transitions to open space,and is described in the next section. Tassajara Creek functions as a major regional wildlife corridor,providing uninterrupted connections to Hidden Valley,Mt.Diablo,Morgan Territory,Camp Parks,Black Diamond Mines and Contra Loma Regional Parks,among others.Biological corridor connections from Tassajara Creek to open space within and outside the Specific Plan Area should be provided through Tassajara Creek and its tributaries.Biological corridors are open space areas that provide natural cover and habitat for wildlife movement and reproductive exchange between plants.To function properly,biological corridors require sufficient width to allow unimpeded movement.Corridors require connections to larger expanses of protected open space.Where the wildlife connections along Tassajara Creek or its tributaries would be impeded by development,such as road crossings,wildlife underpasses should be provided to mitigate impacts.California Department of Fish and Game should be consulted on a case-by-case basis to review underpass dimensions, placement and treatments to ensure compatibility with wildlife.Super span culverts are available that allow for a natural bottom favorable to wildlife.It may become necessary to fence and/or vegetate near the culvert to funnel wildlife into safe passage and away from roads. The removal of the drop structure under Highway 580,under consideration by the County and Zone 7 would be highly beneficial to wildlife movement. 6.11 Landscaping of Trails and Adjacent Development Landscape plans should employ unifying design principles for the entire Tassajara Creek stream corridor and its tributaries.The City of Dublin will evaluate submitted trail landscaping treatments for their compatibility with other properties along the stream corridor.Where single loaded streets abut the stream corridor,landscaping should not interfere with the ability of local police to visually inspect the trail while driving by. Where the stream corridor abuts parks,the park landscaping and grading should integrate the stream corridor by linking the trail with park circulation and using compatible landscaping.Active park uses however,should not be allowed within 100 feet of the riparian corridor in the creek channel. Storage and loading facilities and dumpsters associated with adjacent commercial development,should be screened from trail views with appropriate landscaping. Because the groundwater table at the trail locations is so removed,permanent irrigation may be required to sustain plantings,which is consistent with the landscaping and fire management goals. Alternatively,very drought tolerant species can be established with temporary irrigation systems.Table 5 lists recommended prohibited landscaping species that are known to invade and overtake natural areas. 75 The native riparian and oak woodland species provided in the restoration plant palettes are among the many species native to the region that if used in the landscaping would be compatible with the restoration efforts,and would provide bird habitat.The riparian species,if utilized in the trail and adjacent trails landscaping,would likely require permanent irrigation.If oaks are used,plantings under oaks should follow the guidelines specified below for oak plantings.Suitable tree,shrub, grass and forb species are presented for restoration,and landscaping plants can be selected from these for maintenance and aesthetic considerations. 6.12 Interpretation Through implementation of the Specific Plan,the City of Dublin faces the challenge of encouraging public access and enjoyment of the stream corridor,while protecting sensitive nesting periods of both resident song birds and other wildlife species.Appropriate interfacing of habitat with urban elements is accomplished with buffers,trail design and interpretation.The rich ecological and aesthetic resources of the stream corridor present numerous opportunities for interpretation.A simple and inexpensive vehicle for interpretation and community involvement is the installation of bird nest boxes,described below. Interpretative signing can focus on natural features and natural processes of the riparian ecosystem. Intriguing educational captions can focus on raptors or other inviting wildlife subjects.The numbers of species using a culvert underpass for safe passage is a possible topic.Natural processes that convey the dynamic and forceful nature of natural river systems can be illustrated along the trail.Riparian vegetation is dependent upon the natural disturbance of flood flows to regenerate,which can be illustrated by the range in age and habitat structure.Selected aquatic environments present interactive opportunities for children to observe natural behaviors and appreciate habitat protection. Sensitive aquatic habitats,such as those known to support California red-legged frog,should not be the focus of interpretation or a trail designation,because it will draw undesired attention to the habitat and is known to result in poaching of the species. Assistance in development of an interpretation program can possibly be obtained through the Alexander Lindsay Junior Museum in Walnut Creek,or East Bay Regional Park District. 6.13 Installation of Bird Nest Boxes Natural tree cavities are relatively rare in most habitats.The availability of nest sites for cavity- nesting birds probably limits the numbers of these species along the creek corridor.The installation of nest boxes or nest shelves would provide nest sites and cover for many species of birds,as well as mice and other small mammals.Volunteer labor to install nest boxes or nest shelves can possibly be obtained through the Alexander Lindsay Junior Museum in Walnut Creek, local Scout troops,and school-age children in Dublin.The City of Dublin can encourage these groups by disseminating this information. - 76 /,� Nest boxes are available in most garden centers,many lumberyards,and sometimes in craft stores and the`Nature Company'catalogs.Prices vary depending upon size and quality but most nest boxes cost between$8 and$20.Sources of nest boxes include:Wild Birds Unlimited,692 Contra Costa Blvd.,Pleasant Hill,CA 94523,(510)798-0303;Backyard Birds&Co.,717 S. Broadview,Springfield,MO 65809-0712;For the Birds!,P.O. Box 491,Hovland,MN 55606; and Wildlife Studio,7 Patton Road,Bedford NH 03102. Figures 21 and 22 illustrate several nest box designs and a sample building plan.Nest boxes are easy to construct.Nest boxes should be made of pine,fir,or some other soft lumber.The walls should not be over one inch thick.Boxes with open or removable roofs are recommended,to allow access to the interior.Boxes or shelves may be unfinished or painted. If the box or shelf is painted,use neutral gray,brown,or green.Excessive heat can kill nestlings.Ventilation can be provided by drilling two small holes in the floor,and two small holes in the top of one of the walls. It is not efficient to have too many nest boxes in a limited reach of creek,as birds are territorial animals.Therefore nest boxes should be placed 30 to 100 feet apart,and neighboring boxes should be designed to attract different species.Along the linear corridor of the creek,no more than four to six boxes should be placed every 500 feet.It may not be necessary to be so restrictive with the number of nest shelves installed. Nest boxes should be cleaned after every nesting season.All old nest material,remaining eggshells,and other debris should be removed. 77 ,C/ ALDP., SA, "AV t im i v k-7_4a.L ir iA .....c. ,..... ,rli,, A at Ortiz - ,rtt. ,-, INI I lid li )1( ( Ii 7\ 1 ,* 'i ..• „ _ .,_ , 0--- .... Figure 21 (3 __.. , rillik - 4 i , An II _°1*---41111N1h0.- H)114 Aihia.4... \ ' i. \,\ ,� I I , 11 mums , I I I ' ' , ,/(.,-*'-'-- I) 11 0 i IP tA7 1 i\i'\ 0\ la 'iv, „ li, li 1, I' -' .' \ (i l ',\ I' i' \I varJa I (I i i I Figure 22 `q • Bats are also an important component of the native ecosystem,and development has greatly reduced their habitat.Bat nest boxes can also be purchased or constructed with kits available from the Lawrence Hall of Science gift shop in Berkeley,(510)642-1929.Information on bats can be obtained from Bat Conservation International,(800)538-BATS. Some of the species that nest boxes or nest shelves would benefit include:chestnut-backed chickadee,house finch,American robin,Bewick's wren,white-breasted nuthatch,ash-throated flycatcher,barn swallow,and black phoebe.Bat species that occur locally include:California myotis,little brown bat,Mexican free tail bat,big brown bat and the Brazilian bat. 6.14 Restoration Treatment of the Three Reaches Restoration treatments in the Tassajara Creek corridor and its tributaries will vary as a function of current conditions,project goals and proposed modifications.Guidelines for restoration treatments,from exotics eradication to irrigation are presented below,and their application will vary with the extent of restoration treatments incorporated for a particular reach.For example, plants will be established at greater densities in bare soil areas and less intensively when interplanting a well-vegetated reach. As discussed in detail in the section on groundwater testing below,each native riparian species has unique groundwater distance requirements and tolerances.The proper placement of plants within specified planting zones should reflect their natural positions with respect to the groundwater profile,and is based on their ability to reach the water table or to tolerate drier conditions.In the Tassajarn Creek system,riparian species can be self-sustaining in the absence of permanent irrigation when placed in the creek channel itself.Riparian plantings on the flood plain terrace however,are not feasible because of the distance to the groundwater table. The flood plain terrace outside the creek channel should be managed for low growing,low maintenance non-irrigated grasses.This zone,extending along either side of Tassajara Creek and its tributaries,is too high above the water table to support volunteer willows,and is expected to support native and annual grasses and wildflowers.The zone will vary in width,depending upon the size of the stream corridor cross section and can be managed with mowing,which is preferable to disking.Thorough control of the noxious weeds,such as yellow star thistle will be necessary prior to seeding,as will appropriate debris removal and seed bed preparation. Complete eradication of the exotics should not be expected,however a competitive edge can be given to the natives if an aggressive exotics eradication program is pursued.If seeded in the fall prior to onset of rains,no irrigation should be required.A seed mix for this zone is provided and can be modified with California Department of Fish and Game approval. 80 ..!(7... The lower reach of Tassajara Creek,between Highway 580 and Gleason Road requires substantial restoration plantings in the creek channel,due to the proposed modification in Subreach 1 and the lack or habitat structure and diversity in Subreach 2.Plantings with native riparian species are required by California Department of Fish and Game and are consistent with the Specific Plan.Because plantings will increase resistance to flood flows,hydrologic modeling and sizing of the channel must account for the vegetation.Zone 7(Mr.Jack Fong,personal communication)has suggested the exclusion of willow from the plant palette for this reach,but inclusion of the other riparian tree and shrub species.This compromise is acceptable for this reach only,but the hydrologic models should anticipate naturalization of some willows.Native plantings should be at densities sufficient to provide wildlife habitat,for example trees on 25-35 foot centers(25-35 feet apart),and shrub masses a minimum 25 feet apart with the shrub plants themselves on 3-10 feet centers.Actual spacing is dependent upon the species used and the available groundwater.A palette for native grass and forb species is also provided. The tributaries of Tassajara Creek present significant opportunities for mitigation.Many are currently disturbed or will be sufficiently modified to require considerable mitigation plantings. If a tributary will not be improved through the mitigation of project impacts,restoration of tributaries that are important to wildlife movement is recommended.In particular,native revegetation near wildlife undercrossings,complemented by fencing,is critical to the functioning of the stream corridor.Locations where large debris is removed will require native revegetation. Native plantings,consistent with the plant palettes provided for tree,shrub,forb and grass species should be at densities sufficient to provide the wildlife habitat.Groundwater availability of the subject tributary should be understood and should dictate final planting densities.Where seeps and springs occur,densities may be greater than where conditions are drier.Approximate spacings are:trees on 25-35 foot centers,and shrub masses a minimum 25-35 feet apart with the shrub plants themselves on 3-15 feet centers.Actual spacing is dependent upon the species used and the available groundwater. The middle reach of Tassajara Creek,from Gleason Road up to and including the East Bay Regional Park District staging area,although primarily well vegetated and requiring no restoration,has isolated patches requiring exotics eradication,debris removal and restoration plantings.A qualified biologist should identify the areas that merit restoration,and the species selected and planting densities should reflect the species and densities observed in the adjacent intact(reference)areas.The planting zones for the various species can be readily interpolated through the adjacent vegetative indicators.Approximate spacings are:trees on 15-25 foot centers,and shrub masses a minimum of 15-25 feet apart with the shrub plants themselves on 3- 15 foot centers. The upper reach of Tassajara Creek above the East Bay Regional Park District staging area to the County line,presents three scenarios,all of which should be identified by a qualified biologist and hydrologist.First,there are stretches along Tassajara Creek in this reach that are well vegetated and require no restoration.These stretches will be further enhanced by the eventual --- 81 exclusion of cattle and horses in the creek,pursuant to the EIR and Specific Plan.Second,there are stretches requiring exotics eradication,debris removal and restoration plantings.Third,at the very northern stretch of Tassajara Creek,many of the banks are near vertical or overhanging,and there are numerous piles of rubble,some of which should be removed.Inherent in the planning and restoration treatment of this area is adequate hydrological and biological wildlife,discussed in earlier sections.Restoration in these steep banked areas could entail leaving the banks alone, seeding bare soil areas on the banks with natives where feasible,and providing mitigation for public safety.Near vertical banks can be seeded in some cases,but planting should be prohibited because the activity will exacerbate erosion and is prohibitively dangerous to contractors.Should the land owners desire,or East Bay Regional Park District require,isolated repairs of vertical or overhanging banks could be made and revegetated with natives,for the sole purpose of public safety.Treatment of these banks is not indicated for biological and hydrological reasons,and should be left to the discretion of the City of Dublin,the landowners and East Bay Regional Park District.(Zone 7 has indicated that the conditions of this reach are inconsistent with their maintenance criteria and they will not likely take management of the flood channel north of the East Bay Regional Park District staging area.)If isolated repairs were made,significant efforts should be made to preserve the unique aesthetic values in many of these banks.Riparian plants are expected to regenerate naturally when cattle no longer water in the creek.Areas denuded by debris removal should be planted and/or seeded.Species and planting densities should reflect the species and densities in the adjacent intact(reference)areas.Seeding in this reach may require adjustment of the palette should the soils tests reveal salinity or other severe conditions.The alkali grassland above the creek to the east supports several native grasses adapted to the unique soil conditions. 6.15 Exotics Plant Eradication The restoration program requires both the initial eradication of invasive exotics prior to revegetation and the continued control of these aggressive species as they attempt to recolonize the site.Construction and site-modifications will create open areas that are prime sites for opportunistic exotics.Given the urbanizing setting and constant exposure to exotic seed sources,complete eradication is not realistic.For these same reasons,in order to recapture the site for natives,certain exotics should be completely removed prior to the revegetation phase.In the follow-up maintenance program,the spread of the exotic species is checked.Desirable native plants,including riparian and upland tree species,salt grass,mugwort,California wild rose,poison oak and wetland plants should be protected during eradication efforts. Exotic species to eradicate include,but are not restricted to:annual grasses,yellow star thistle, cocklebur,common fennel,thistles,nutsedge,mustard,curly dock,prickly ox-tongue,rabbits foot grass,Bermuda grass,Scotch broom,tree tobacco,and poison hemlock. To effectively control exotic plants throughout the Tassajara Creek corridor and its tributaries,a wide array of treatments should be available,including conservative application of herbicides, manual and mechanical methods.Mechanical or manual eradication of exotic species should take 82 f, L�1_- precedence over chemical eradication whenever it can be economically justified,in order to minimize potential impacts to aquatic organisms.Frequently,a combination of mechanical removal and localized chemical treatment will eradicate the plant while minimizing the use of chemicals and environmental contamination. The restoration program should include a discrete exotics eradication plan that is conducted for a sufficient time period(1-12 months is not uncommon)to ensure adequate site preparation. In final plans and specifications,the revegetation specialist should develop a list of exotic plants to eradicate,specify detailed eradication methods for each species,specify tolerances for these plants after treatment,and identify the seasonal windows when target species are most susceptible and the removal operation is most cost effective.Timing of seed production of the exotics should be considered when planning eradication efforts. Wherever possible,organic debris generated by the eradication of exotic species should be removed manually,not mechanically(i.e.,no heavy equipment).Appropriate disposal of organic debris should be ensured. For many exotic species,if there is any seed present at the time weeds are killed,the seed heads,or in some cases,the entire plant,should be bagged and disposed of properly off-site.This holds for tree tobacco and cocklebur,but not for yellow star thistle and annual grasses. Although manual eradication is preferable,it is labor intensive and can require several months,or years,of repeat treatments.Combining manual eradication with restricted chemical treatments provides effective results in a short time period.If this project does not have the schedule flexibility to dedicate years to eradication of exotic species,the limited use of an herbicide is recommended. The only herbicide that could be used within 75 feet of the creek is glyphosate,trade name Rodeo, in a wetland formulation.Under no circumstances should herbicides should be used within approximately fifteen feet of creek water and aquatic sites,or where spray drift or runoff could contaminate the water.Roundup,glyphosate with a surfactant that is toxic to aquatic organisms could be used in controlled circumstances for upland applications. The final plans and specifications should prescribe all chemical applications and address the number of applications,treatment of re-growth,schedule and climatic constraints,disposal of spent containers and safety precautions. Specifications should emphasize that the herbicide contact only the target plant,with no chemical contacting the surrounding vegetation.Broadcast spraying of herbicides is not recommended. Painting the chemical directly onto a fresh wound of the target plant produces the optimal effect of controlling exotics while minimizing chemical use.All chemical applications should be conducted under the supervision of a Licensed Pesticide Applicator and a knowledgeable revegetation specialist.When treating woody species with chemical,only the cambium section of the outer trunk is painted and the effective time lapse between cutting and treatment is limited to two minutes or less. 83 • Annual ruderal weeds may be grubbed out manually,weed whipped or mowed. 6.16 Debris Removal Non-organic debris or rubble has been dumped into the Tassajara Creek channel and its tributaries at various locations throughout its course within the project area.The debris includes concrete rubble,asphalt,trash,autos,tires and more.In the final planning phase,restoration planners should evaluate situations in which the concrete may be used in hard structures. Much but not all of the debris or rubble should be removed.All rubble should be mapped and evaluated with the following ecological and aesthetic criteria to determine whether it should be removed.Prior to removal and as a part of evaluating the feasibility of removal,the hydraulic influences of its removal should be deternned by a qualified engineer. Rubble should be removed from banks and the low flow channel wherever it has the potential to affect water quality or is hazardous,such as asphalt,tires,autos or barrels of unknown substances. Rubble should be allowed to remain in the low flow channel where it is not hazardous or detrimental to water quality.Rubble should be allowed to remain on the banks,where it can be demonstrated that it is not hazardous or detrimental to water quality,cannot be seen from trails or overlooks,is not readily removed by equipment available during the construction phase,and is not greater than 100 square feet in size. ' I All removal of rubble should be followed with a planting and or seeding restoration program. Final plans and specifications should address removal and disposal of non-organic debris. If not useable in the project,the debris should be removed from the site and disposed of properly in a landfill. Final plans should address the removal and disposal of organic debris.In many cases,thatch from dead exotic vegetation should be removed from the site to avoid further invasion of the site with the undesirable seed or propagules. 6.17 Soils Testing and Treatment Soil testing is an integral step in the design and implementation of a successful restoration program because soil toxicity or incompatibility problems,such as excessive salinity,alkalinity or the overabundance of certain elements,such as boron,cannot be readily determined in the absence of agricultural suitability tests.These problems have the potential to result in widespread plant mortality or poor growth performance if left undetected.The primary goals of the soils testing is:to identify an appropriate plant palette,identify difficult soils and possible soil treatments,detect the variation in the soils throughout the restoration sites,and to determine cultural regimes during establishment maintenance.At least three composite soil samples should 84 g be collected from different planting zones(low,mid and high),at a minimum of half mile intervals on both sides of the creek(totaling 6 samples)wherever restoration plantings are planned.A single composite sample is collected by sampling soil to a depth of 24 inches from five sub-locations within that planting zone,for that distinct reach and side of the creek The soils samples should be properly labeled and sent to a qualified soils laboratory for an agricultural suitability test and analysis. A copy of the soils report and recommendations should be provided to the City of Dublin when submitting restoration or mitigation plans for review.Recommendations may correct for pH or fertility problems,or improve permeability.However,certain soil conditions should dictate a change in the plant palette rather than the soils,if the soils support a unique plant community, such as alkali grassland.The restoration plans should reflect the soils analysis and recommendations.A qualified laboratory experienced with native restoration and known to give thorough and accurate analysis is:Dr.Gam Wallace,Wallace Laboratories,365 Coral Circle,El Segundo,CA 90245(310)615-0116. Prior to any site disturbance,a qualified restorationist with experience in topsoil salvage and storage should be consulted to determine the need and options for topsoil salvage and storage. In the event that topsoils are removed during site disturbance,a qualified soils scientist should be consulted on the replacement of topsoils to help ensure that restoration plantings succeed. If soil is stockpiled,it should be protected from moisture to preserve microorganisms living in the soil that are beneficial to native plants. Stockpiling of soil for long periods of time,however,will destroy desirable microorganisms,such as mycorrhizae(beneficial fungi living in the soil).Soils should not be stockpiled for more than 16 months,preferable less than 12 months. Wetland soils should not be mixed with upland soil stockpiles.A qualified restorationist should monitor any wetland soil excavation to ensure that soils are not excavated too deeply,which would - dilute the value of the soil layer,or too shallowly,leaving behind useful material. Topsoils for all soils to be stockpiled should be separately piled to enable the contractors to distinguish between subsoils and the more valuable topsoil.Similarly,all piles of soil that are stockpiled should be labeled and/or mapped on plans to allow contractors to distinguish between them for the purposes of replacement.All salvaged and stored soils should be placed on ground tarps at approved staging areas and piles.Salvaged soils should be placed on a geocloth or some other type of membrane to prevent contamination and moisture uptake from the ground during storage.Soil piles should be covered with plastic sheeting and staked to hold the sheeting in place. The covers should be reflective to reduce heat,but should be placed in a manner which allows venting in order to evacuate heat produced by decomposition.Soil stockpiles should be linear rather than one large heap to reduce decomposition and heat diffusion.This would allow for limited drying of soils during storage.Piles should not exceed four feet in height When replacing stockpiled soils and recontouring,the contractor should account for settling. 85 It is recommended that soils testing and groundwater testing,as described in the next section, should be conducted concurrently. 6.18 Restoration Plant Palette Table 1 shows the species recommended for use in creek restoration,grouped as trees,shrubs,and grasses and forbs.The majority of these species listed in the plant palette are local to the region. Some of the species are native to other regions of California and were included for their wildlife values,aesthetic attributes,and contribution to wildlife species diversity.Additions may be made to the plant palette if the species are native to the region.Species diversity is essential to restoration and should more natives become commercially available in the future,these certainly may be included in the palette.The table presents the recommended propagation method,particular wildlife habitat value,and a slope stabilization rating for each species.Applicant's plant palettes may vary from Table 1,but should be restricted to species native to the region. For many of the same species in the plant palette,Table 2 gives the growth habit,general habitat description.The last column is left blank to assist restoration planners in the field in noting whether the species is growing in the reach for which the restoration is being planned.Species from the plant palette may be used anywhere in the project area,however an emphasis on the species performing well in the reach is recommended. Serious consideration was given to commercial availability in the development of the plant palette. Although limited in numbers,seed suppliers and nurseries that can provide the native plant and seed materials do exist.In addition,many of these operations will provide custom seed and plant collections as well as custom propagation of locally collected stock. 6.19 Groundwater Testing and Planting Zones Planting zones within riparian habitats are determined by the distance to the groundwater.In a system such as Tassajara Creek,groundwater is close to the surface at the midpoint of the low flow channel and drops on either side of the low flow channel,with the groundwater profile resembling a parabola.The depth to groundwater increases with the horizontal distance from the centerline of the creek,and the vertical distance above the low flow channel.Creek downcutting increases the distance to the water table,and existing trees may have established in times when the groundwater table was closer to the surface.Native plants have adapted to natural conditions and can survive in the absence of permanent irrigation if established on appropriate sites.Each native riparian species has unique groundwater distance requirements and tolerances.The placement of plants within specified planting zones should reflect their natural positions with respect to the groundwater profile,and is based on their ability to reach the water table or to tolerate drier conditions. • r I _ 86 The groundwater profile and associated planting zones should be established for any reach subject to a planting plan(Figure 23).Distance to groundwater can be determined with piezometers or can be interpolated through vegetative indicators by a qualified plant ecologist,who can account for downcutting effects on the water table.Local groundwater studies indicate that groundwater supplies for plantings in the lower reach may be severely limited,due to infiltration to the deep aquifer.Groundwater testing is imperative. Riparian tree species should be planted in zones defined by proximity to the water table,shade tolerance,and cultural requirements. The lowest planting band in the creek channel,within three feet of the water table,will support the three willow species in the plant palette.Note that distances to the water table are approximate and may vary slightly with the particular site. The next planting band within the creek channel,located three to six feet above the water table,will support cottonwood,box elder,ash and alder. The next planting band within the creek channel,located six to ten feet above the water table,will support sycamore,valley oak,buckeyes and walnut. The upland species typically associated with.a riparian zone are established within a deeply incised channel and on the top of the bank.The species to be planted at distances greater than ten feet above the water table included:live and blue oaks and big leaf maple. Plant layout should reflect the limited shade tolerance of most riparian species.Bay trees,however, are uniquely shade tolerant and can be interplanted from three to ten feet above the water table,in areas with an existing partial canopy. Cottonwood and willows should be emphasized in plantings because they provide rapid slope stabilization and tree cover for both the stream channel and slopes.In addition,cottonwood and willows are the dominant species in the better developed local riparian stands.Because of their rapid growth rates,these species are especially appropriate for planting into bioengineering treatments. The flood plain terrace located outside and above the creek channel should be high enough above the groundwater table to discourage natural recruitment of the riparian tree species,such as willow and cottonwood.This large upland area,which serves as a buffer to the riparian corridor,will be maintained with a low ground cover,primarily native and annual grasses,and will provide the flood control for 100 year flows. • The distance to the groundwater table for the landscaping associated with the trails will largely exclude riparian species.In these landscape strips,very drought tolerant species native to the 87 l� region should be emphasized,as discussed above in a section on landscaping of trails and adjacent development. 6.20 Planting Under Oaks • Califomia's native oak species are adapted to the region's dry summers.Consequently,any landscaping or wildlife habitat plantings within the driplines of established oak trees in the Tassajara Creek corridor and its tributaries should have water needs that are compatible with the oaks to minimize the chance that overwatering would promote oak root disease.Planting under existing oaks should be restricted to the species in Table 3.Both wildlife habitat enhancement plantings near the channel and native landscaping under oaks near the trail should incorporate appropriate species from Table 3. • • 88 Planting Zones • . *if - '.. Ati trill- \ toWifk.k' mor . 414.) ?I', : , i , 11,,1,ii II • le' iliN. r • 41111,‘fr..4...-:‘4641-:...4:1 . iii . ' ". ` Zone 4 Zone 3 Zone 2 Zone 1 I Zone 2 Zone 1 Zone 4 Common Name(Scientific Name) Zone 1 Zone 2 Zone 3 Zone 4 Willow(Sa/ix spp.) X White alder(Alnus rhombifolia) X X Box elder(Acer negundo ssp.califorica) X Oregon ash(Fraxinus latifolia) - X Fremont cottonwood(Populus fremontii) X California bay(Umbellularia californica) X X Buckeye(Aesculus californicus) X Black walnut(Jug/ans hindsni - X Western sycamore(Platanus racemosa) X Valley oak(Quercus lobate) X X Big leaf maple(Acer macrophy//um) X Madrone(Arbutus menziesii( X Coast live oak(Quercus agrifolia) X Blue oak(Quercus doug/asii) X Figure 23 ry l'J1 Plantings should not be within ten feet of oak trunks.Care should be taken to ensure that irrigation drains away from oaks.If plantings need water through the first summer,a mulch-covered above- ground drip irrigation system should be used. If open areas under oaks are desired to preserve view corridors,Elymus triticoides and E. glaucus plantings are recommended. 6.21 Container Sizes and Plant Spacing Figure 24 illustrates a typical planting detail for installation of container plants and blackberry cuttings. Appropriate container sizes for trees are:citrus pots or five gallons for planting pockets,minimum of one gallon size for interplanted areas,and minimum of one gallon size for planting open areas. Citrus pots are the optimum container because they support a deep root system and moderate top size at planting time;pot size is 8 by 14 inches and volume is four gallons.If all trees are grown in citrus pots,restoration success will be greatly enhanced.Trees planted to mitigate removed trees should be citrus pots or greater in size. If employed in a bioengineering treatment,interplanting of trees in planting pockets should allow approximately ten to twenty foot spacing between trees.Citrus pots are preferred,but five or fifteen gallon containers are acceptable,and pole cuttings may be used for willow and cottonwood plantings. Trees planted in bare areas,graded areas,or where debris was removed or exotic plants were eradicated,should be spaced according to the species and the groundwater availability in the reach. Spacing is discussed in the section on restoration treatments above.Spacing and layout should always emulate a natural configuration.The container size can be citrus pots,five gallons or one gallon plants,but citrus pots are favored. Shrubs should be liner or one gallon size and planted in shrub masses as described in the above section.. The planting pattern should emulate natural spacing and distribution patterns.Shrub masses or groupings can be planted in openings where they will not be shaded out by the tree canopy. Blackberries and native roses may be planted in thickets on eighteen inch spacings with a minimum of ten plants per thicket.These shrubs may also be interplanted or planted over large areas,for their slope stabilization and buffer strip values. Since purple needle grass is a poor seeder,liners may be used to establish stands of this attractive bunch grass. 90 Blackberry Detail `1 chill). [ u.-.—o i :11141 4a'-- Ir011= l�—illl II-II) 1(- -11t-alu' Planting Detail ,...044r160: . till n .._0�'i1 tl I= ',: �' h�IIIII- I.:_ .I(:-II 0._i' ,i,wlll tl 0 - .ii =.tn 0 =Olrkr== ) tr—It= Jvaii !O Planting pit to be twice as wide O With water flowing slowly into the hole, and twice as deep as plant container. replace backfill material up to 2/3 the height of the root ball,moistening, tamping OBreak up large clods. and settling all around the plant OTimed-release fertilizer tablets O Fill remaining portion surrounding the top (2 for each planting pit) of the root ball with more backfill.Make `J Fill planting pit with water and sure that the collar is still higher than grade allow to percolate(drain) into subsoil Create an irrigation basin outside the dimension OPlace some backfill material into O of the hole using remaining backfill and native soil the bottom of the pit,moisten and tamp, and mound slightly c Apply a generous portion (approx.3'deep) coarse. © Set plant root ball atop the moistened organic,weed and disease-free mulch;topdress around backfill so that the plant collar is 1" exposed collar and inside the entire basin area.Taper higher than the finished grade. away from branches to avoid stem rot. /Figure 24 6.22 Plant and Seed Procurement The plant species provided in the plant palette have been carefully selected for their adaptation to the habitats to be enhanced and created,and because they are native to the area.These species, properly planted and cared for offer the best chance of survival and success in the absence of permanent irrigation.Therefore,only species from the approved list of native species should be planted within the Tassajara Creek corridor and its tributaries,including the wildlife habitat and trail landscaping areas.Species substitutions by contractors should be with species from the approved plant palette and specifications should state that substitutions should be avoided if possible.Should substitutions be necessary,approval by a representative of the City of Dublin and the revegetation specialist will be required. Grass and forb species for the creek banks in the riparian areas are limited to native species.While species on in the flood plain terrace mix emphasize native species,non-native grasses are expected to invade the terraces.If erosion control is a consideration,a non-native nurse crop Plantago insularis(at approximately 20 pounds per acre)can provide rapid germination,stabilizing soil until the desired plants are established.Plantago insularis is recommended because it does not compete with natives and is non-persistent,i.e.,it dies within a few seasons. To protect the gene pools of the local native plant populations and help ensure the success of the wildlife habitat and landscaping plantings,the use of local sources of container plants and seed are encouraged.Local is either from the Tassajara Creek watershed or from southern Contra Costa County or northern Alameda County.Suppliers and nurseries providing stock should certify the origin of their seed and plants.Additional information may be requested,such as the number and spacing of donor plants.The revegetation specialist should review proposals to use stock that does not originate from this area. Plants and seed should be ordered in advance(or contract-grown)to ensure that the species,sizes, and plants of local origin are available when needed. Advanced ordering is absolutely critical and its importance cannot be over-emphasized. 6.23 Mycorrhizal Fungi Rapid growth and establishment of plants on a restoration site is vastly improved with the presence of mycorrhizal fungal associates of the plants.Mycorrhizae are specialized fungi found on plant roots.A mutualistic relationship exists between plant roots and mycorrhizae.Plants benefit from increased ability to take up nutrients and withstand drought when mycorrhizae are present.This v' relationship is essential to the growth rate,well-being and longevity of natural plant communities. Site disturbances,such as grazing,can cause mycorrhizal fungi to die out through elimination or suppression of their host plants.Although mycorrhizal fungi can re-invade if suitable host plants and other conditions are in place,re-invasion is often very slow.Utilization of mycorrhizal fungi markedly increases the success of restoration on disturbed or degraded lands.The presence of mycorrhizal fungi is know to favor native plant establishment over weeds.Additionally,it has been 92 JD7, demonstrated that the presence of mycorrhizal fungi is critical for regeneration of natural ecosystems in arid lands. The presence of the appropriate mycorrhizal associates makes the difference between installing an artificial landscape and restoring a functional ecosystem.Soil biology is restored over the long term through slow establishment of native plants.Alternatively,container plants procured for restoration can be inoculated with the appropriate mycorrhizae,which then spread to other plants on the site as they become established.Tree of Life Nursery in San Juan Capistrano,California provides inoculation of their mature plants. 6.24 Storage and Handling of Seed and Plants All container plants should be hardened-off at the nursery prior to delivery or pick-up.The extent of hardening-off should be appropriate to the season of the year when planting occurs. Storage,handling,and inspections of the seed and plants should be addressed in the final plans and specifications.Plants should be inspected for correct species and quantities,health,vigor, acceptable root-to-shoot ratio,circling roots,growth and form,and should be visibly free from pests and diseases. Plants and seed should be kept in a cool dry place,protected from wind,heat and other conditions which would damage or impair viability,both during delivery,and when temporarily stored on site prior to planting.Onsite storage time should be minimized. 6.25 Commercial Sources of Plant and Seed Materials Several nurseries experienced in propagation of California natives are listed below.As discussed below,planning is required to allow custom growing of genetically local stock for the Tassajara Creek watershed or the local counties.Current availability of plants and seed from the plant palette for the wildlife habitat and trail landscaping areas was not verified for this report. Nurseries include: Cornflower Farms P.O.Box 896 Elk Grove,CA 95624 (916)689-1015 Los Robles Native Plants P.O.Box 449 Gerber,CA 96035 (916)385-1205 93 13S 7 ... • Native Here Nursery • 101 Golf Course Drive Berkeley,CA 94708 (510)549-0211 Pacific Open Space P.O.Box 744 Petaluma,CA 94953 (707)769-1213 { Skylark Wholesale Nursery 6735 Sonoma Highway Santa Rosa,CA 95405 (707)539-1565 Wapumne Native Plant Nursery 3807 Mt.Pleasant Road Lincoln,CA 95648 (916)383-5154 Yerba Buena Nursery 19500 Skyline Blvd. Woodside,CA 94062 (415)851-1668 Additional sources of plant materials include the California Department of Forestry Reforestation Center in Davis(916-753-2411),and the California Conservation Corps Native Plant nursery in Napa(707-252-7783). Seed companies specializing in native seed are listed below: Albright Seed 487 Dawson Drive,#5-S Camarillo,CA 93012 (805)484-0551 Conservaseed P.O.Box 455 Rio Vista,CA 94571 (916)775-1646 94 l (, Hedgerow Farms 21740 County Road 88 Winters,CA 95694 (916)662-4570 Lamer Seeds P.O.Box 407 Bolinas,CA 94924 (415)868-9407 Pacific Coast Seed 6144 Industrial Way,Suite A Livermore,CA 94550 (510)373-4417 S&S Seeds P.O.Box 1275 Carpinteria,CA 93013 (805)684-0436 6.26 Genetics Conservation Guidelines Restoration goals establish the need to use seed and plant stock from local gene pools.The goals reflect the extent of the City's desire to assume this commitment.Custom propagation is not necessarily more expensive,but it requires advanced planning. This plan endorses a moderate approach,emphasizing genetic conservation of species currently growing within the watershed,followed by a best effort to collect from the Alameda/Contra Costa area if watershed propagules are limited.This approach would include seed and cutting collections from donor plants within the Tassajara Creek watershed,and purchase of seed and container plants from elsewhere in northern Alameda County or southern Contra Costa County.Procuring local stock from trees is a priority,however,because they are long-lived.Several species in the plant palette,such as the native bunch grasses,cannot be collected locally,but their use in restoration would increase diversity and greatly enhance aesthetic and wildlife values.It should be remembered that where local populations have been extirpated,introduction of non-local natives cannot cause genetic contamination. Custom collection programs should be protective of donor populations by avoiding over-collecting and by spreading collections across a broad area.These collections should be appropriately labeled, stored and handled.Volunteers may be employed to collect the plant propagules,while qualified commercial operations can process the seed and grow the plants. 95 Jl.O • To ensure adequate representation of the genetic resources within the project area,seed or cutting collections from local plants should be from between 25-50 donor plants.Donor plants should be at least 100 feet apart and should be found within the Tassajara Creek watershed. Collection sources should be documented so that in the future,local stock can be distinguished from non-local or contaminated stock. Seed suppliers will contract to collect seed from specific locations.They should develop and follow state-of-the-art techniques for handling,storage,and pre-treatment techniques. If planting is delayed,the plants produced for the project may have to be repotted to prevent them from becoming root bound,which will increase the cost of the stock.Purchasing from existing inventories of suppliers and nurseries obviates this risk but because existing inventories rarely meet the standards for local stock,last minute purchases may result in non-local stock. 6.27 Techniques of Local Cutting Collections Cuttings collected from local blackberry,willow and cottonwood donor plants helps contain the cost of restoration plantings while assuring that genetically local stock is used for project plantings. Table 4 outlines a schedule of availability for making collections of many of the species required for the project. For each species,all cuttings should be taken from 25-50 donor plants spaced over 100 feet apart and from locations in the Tassajara Creek watershed.Guidelines for cutting techniques also apply to pole plantings. The number of cuttings taken from each donor plant should be approximately equal. Cuttings or poles may be taken from dormant cottonwood donor plants and directly outplanted. Pole cuttings may range from two to ten feet in length,depending upon the final planting location. If soil moisture at the restoration site is abundant,shorter poles are sufficient.Poles are typically one to two and one-half inches in diameter at the base.Branches and stubs should be removed and the top should be pruned close to a lateral bud.Unrooted poles are planted by placing 75 percent of the length into pre-drilled holes.Holes drilled for pole cuttings need to be only slightly deeper than the pole.While back-filling the planting hole with native soil,care should be taken to remove all air pockets.Storage procedures are the same as those described for willow cuttings. Alternatively,cuttings or poles may be taken from local cottonwood donor plants(as described above)and grown in appropriate containers for future outplanting.A one gallon,citrus pot or five gallon container can be grown in 12 months time.In the event cottonwood seedlings are purchased, both male and female plants should be procured to protect future regeneration.Typically,nurseries sell only male plants because the female plants produce a very unpleasant odor. 96 I) r Willow cuttings may be planted directly on site or rooted at a nursery for subsequent planting. Willow cuttings should be collected from dormant donor plants.Cuttings should be a minimum of two feet long,one half inch to two inches in diameter at the thick end,consist of non-succulent material,and should be planted within two weeks of collection.Interim storage should keep the cuttings cool and moist,hut not wet.The cuttings should be stored at least two nights to allow for drying of the cut ends.The thicker end of the cutting is planted in a vertical hole leaving approximately one fourth of the cutting in the air,or planting 75 percent.To distinguish between the thicker or rooting end from the foliage producing end,the root end can be angle cut at collection time. Watering basins,two and one-half feet in diameter and four inches high should be constructed around each stem to collect water.Mulch should be applied at a depth of four to six inches,with the mulch tapered away from the stem to avoid direct contact with the root crown.Mulch in contact with the plant's stem maintains excessive moisture and promotes disease. • • • 97 /l 2 Table t Recommended Plant Palette TREE SPECIES PROPAGATION WILDLIFE VALUE SLOPE METHOD STABILITY Acer macrophyllum container roosting, cover, food good Acer negundo container roosting, shade, food good 1 Aesculus californica container I roosting, cover, food good Alnus rhombifolia container roosting, shade excellent Fraxinus latifolia container roosting, shade good Juglans hindsii container roosting, shade good Platanus racemosa container roosting, shade good Populus fremontii container, cutting roosting, cover, shade excellent Quercus agrifolia container roosting, food, shade good Quercus douglasii container roosting, food good Quercus lobata container roosting, food, shade good Salix hindsiana cutting roosting, cover, food excellent Salix laevigata cutting roosting, cover, food excellent Salix lasiandra cutting roosting, cover, food excellent Salix /asio/epis cutting roosting, cover, food excellent Sambucus mexicana container roosting, cover, food good Umbellularia californica container roosting, food, shade good 98 J '3 Table 1 . Continued SHRUB SPECIES PROPAGATION WILDLIFE VALUE SLOPE METHOD STABILITY Baccharis p//u/ar/s container cover, food, roosting excellent ssp. consanguinea Diplacus aurantiacus container cover, food good Eriogonum fasciculataum seed cover, food good Garrya fremontii container cover, food good Heteromeles arbutifolia container cover, food good Lonicera hispidula container food good Rhamnus californica container cover, food good Ribes sanguineum container cover, food good Rosa californica container cover, food excellent Rubus ursinus cuttings cover, food excellent Symphoricarpos moth's container food excellent Symphoricarpos rivu/ar/s container food excellent Vitis californica container food good Zauschneria californica container cover, food good 99 Table 1 . Continued GRASS AND FORB SPECIES PROPAGATION WILDLIFE VALUE SLOPE FOR RIPARIAN AREAS METHOD STABILITY Artemisia doug/asiana seed cover excellent Bromus carinatus seed cover, food good Elymus glaucus seed cover, food excellent Elymus triticoides transplant cover excellent Eschscholzia californica seed cover fair Hordeum brachyantherum seed cover, food good Iris doug/asiana diyisions cover fair Lupinus bicolor seed food fair Lupinus densiflorus seed food good Lupinus nanus seed food good Lupinus succulentus seed cover, food good Mimulus cardinalis seed food good Sisyrinchium bellum seed food fair Stipa pulchra container, seed food good This seed mix would be used on side slopes in the riparian area throughout the project area. • • 100 ,1 ) Table 1 . Continued GRASS AND FORB SPECIES PROPAGATION WILDLIFE VALUE SLOPE FOR FLOOD PLAIN TERRACE METHOD/RATE OF STABILITY APPLICATION Achillea millefolium seed / * cover, food good Bromus carinatus seed / 4 lb./ac cover, food good Clarkia elegans seed / * cover fair Elymus glaucus seed / 4 Ib./ac cover, food excellent Eschscholzia californica seed / * cover fair Gilia capitata seed / * cover fair Hordeum californicum seed / 5 Ib./ac cover good Lasthenia glabrata seed / * cover fair Layia platyglossa seed / * cover fair Linum grandiflorum var. rubrum seed / * cover fair Linum lewsi/ seed / * cover fair Lupinus densiflorus seed / * food good Lupinus succulentus seed / * cover, food good Phacelia campanularia seed / * cover fair Plantago insularis seed / 30 Ib./ac none excellent year 1 Sisyrinchium helium seed / * food fair * All species noted with the asterisk are available in a combination seed mix known as "California Native Wildflowers" from Pacific Coast Seed, 7074 D Commerce Circle, Pleasanton, CA 94588, (510) 373-4417. Six lb./ac of this seed mix should be applied The seed for the flood plain terrace should be used only on those areas above the creek channel, maintained for non-irrigated native and annual grasses. This seed mix should not be used on creek side slopes or the riparian terraces within the project area. �_- lo> 1l • Table 2. Growth Habits of Plant Species Recommended for Restoration TREE SPECIES COMMON NAME HABITAT ON SITE Acer macrophyllum big leaf maple mesic slopes, shaded banks Acer negundo box elder riparian Aescu/us ca/ifornica buckeye dry slopes, sunny banks Alnus rhombifolia white alder I riparian, water's edge Fraxinus latifolia Oregon ash riparian Jug/ans hindsii California walnut banks, mid-riparian zones P/atanus racemosa sycamore riparian, bank tops Popu/us fremontii cottonwood riparian Quercus agrifo/ia coast live oak dry bank tops Quercus douglasii blue oak sunny, dry bank tops Quercus lobata valley oak dry bank tops, riparian Sa/ix hindsiana Hind's willow riparian, water's edge Salix /aevigata red willow riparian, water's edge Salix lasiandra yellow willow riparian, water's edge Sa/ix lasiolepis arroyo willow riparian, water's edge Sambucus mexicana elderberry riparian, canyons Umbel/u/aria californica California bay shaded bank tops, north slope, mid-slope �_- 102 ii1 ; Table 2. Continued SHRUB SPECIES COMMON NAME HABITAT ON SITE Baccharis pilu/aris ssp. coyote brush banks, terraces consanguinea Eriogonum fascicu/atum wild buckwheat dry rocky places Heteromeles arbutifolia toyon banks and slopes Rhamnus californica coffeeberry shaded understory Ribes sanguineum red-flowering forest, woods currant Rosa californica wild rose mesic forest, riparian Rubus ursinus California woods, riparian blackberry Symphoricarpos mo//is creeping mesic forest, riparian snowberry Symphoricarpos rivularis snowberry mesic forest, riparian Vitis californica wild grape riparian, mesic slopes Zauschneria californica California fuschia banks, slopes • • 103 V Table 2. Continued GRASS AND FORB SPECIES COMMON NAME HABITAT ON SITE Artemisia douglasiana mugwort riparian, moist places Bromus carinatus California brome dry slopes, woods Elymus glaucus wild rye grass shaded woods, mesic slopes Elymus triticoides creeping wild rye moist or shaded banks grass Eschscho/zia californica California poppy grassy, open places Hordeum brachyantherum perennial wild moist places, meadows barley Iris douglasiana wild iris shaded woods, open forest Lupinus bicolor annual lupine open grassland Lupinus densiflorus lupine grassy slopes Lupinus nanus lupine grassy slopes Lupinus succulentus lupine grassy slopes Mimulus cardinalis scarlet stream banks, seeps, riparian monkeyflower Sisyrinchium be//um blue-eyed grass mesic grasslands, meadows Stipa pu/chra purple dry banks, terraces needlegrass 104 Table 3. Recommended Species for Planting Under Oaks SHRUB SPECIES PROPAGATION METHOD Eriogonum fasciculatum seed wild buckwheat Heteromeles arbutifolia container toyon Rhamnus californica container coffeeberry Symphoricarpos rivularis container snowberry Zauschneria californica container California fuschia GRASS AND FORB SPECIES Artemisia douglasiana seed mugwort Bromus carinatus seed California brome Elymus glaucus transplant, seed wild rye Elymus triticoides transplant, seed creeping wild rye Iris douglasiana container wild iris Stipa pulchra container, seed purple needlegrass 105 Table 4. Plant Availability and Schedule of Local Collections TREE SPECIES PROPAGULE TIME OF YEAR PROPAGULE COLLECTED AVAILABILITY 1 Acer macrophyllum purchase Acer negundo seed fall local Aescu/us californica seed fall local Alnus rhombifolia seed spring local, purchase Fraxinus latifolia seed fall local Juglans hindsii seed fall local Platanus racemosa seed summer local Popu/us fremontii seed/cutting summer/winter local Quercus agrifolia seed summer local Quercus doug/asii seed summer local, purchase Quercus /obata seed summer local Salix hindsiana cutting winter local Salix /aevigata cutting winter local Salix lasiandra cutting winter local Sa/ix /asio/epis cutting winter local Sambucus mexicana seed fall local Umbellu/aria californica seed winter/spring local Local collections made on site, or at off-site locations within Alameda and Contra Costa Counties if seed or cuttings are limited. 106 (- / Table 4. Continued SHRUB SPECIES PROPAGULE TIME OF YEAR PROPAGULE COLLECTED AVAILABILITY 2 Baccharis pilularis purchase ssp. consanguinea Cercis occidentalis seed fall local, purchase Ceanothus integerrimus purchase Eriogonum fasciculatum purchase Heteromeles arbutifolia . seed winter local Rhamnus ca/ifornica seed fall local Ribes sanguineum seed summer local, purchase Rosa californica seed winter local Rubus ursinus cutting winter local Symphoricarpos mollis seed fall local, purchase Symphoricarpos rivu/aris seed fall local, purchase Vitis californica seed fall local, purchase Zauschneria californica seed winter local, purchase Local collections made on site, or at off-site locations within Alameda and Contra Costa Counties if seed or cuttings are limited. 107 J�� Table 4. Continued GRASS AND FORB SPECIES > PROPAGULE TIME OF YEAR PROPAGULE COLLECTED AVAILABILITY s Artemisia douglasiana purchase Bromus carinatus purchase Elymus glaucus seed summer local, purchase Elymus triticoides transplant winter local, purchase Eschscholzia ca/ifornica purchase Hordeum brachyantherum purchase Iris douglasiana purchase Lupinus spp. purchase Mimulus cardinalis purchase Sisyrinchium bellum purchase Stipa pulchra purchase ' Local collections made on site, or at off-site locations within Alameda and Contra Costa Counties if seed or cuttings are limited. 108 ' "�/ Table 5. Recommended Prohibited Species SCIENTIFIC NAME COMMON NAME Acacia spp. acacia Bambusa spp., et al bamboo Muelenbeckia complexa mattress vine • Robinia pseudoacacia black locust Eucalyptus globulus blue gum Ricinus spp. castor bean Cotoneaster cotoneaster Hedera helix English ivy Cytisus monspeliensis French broom Pennisetum sp. fountain grass Arundo donax giant reed Senecio mikianoides German ivy Ulex europaeus gorse Mesembryanthemum chilensis ice plant Cortaderia selloana pampas grass Vinca major periwinkle Pyracantha sp. pyracantha Cytisus spp. broom species Tamarix spp. tamarisk Ailanthus altissima tree-of-heaven Nicotiana glauca tree tobacco 109 Blackberry cuttings should be collected from dormant donor plants.Cuttings should be a minimum of two feet long,one quarter inch in diameter at the thick end,non-succulent material,and should be planted within three days of collection.Interim storage should keep the cuttings cool and moist, but not wet. The cuttings should be stored at least one night to allow for drying of the cut ends.The thicker end of the cutting is planted in a 45 degree angled hole leaving approximately one fourth of the thinner end of the cutting in the air.To distinguish between the thicker or rooting end from the foliage producing end,the root end can be angle cut at collection time. Watering basins and mulch are not necessary. 6.28 Techniques of Local Seed Collections Seed from the species currently growing in sufficient numbers(valley oak,coast live oak,buckeye, California bay,box elder,walnut and ash)should be collected from a minimum of 30 donor plants, spaced at a minimum of 100 feet apart and from locations in the Tassajara Creek watershed.Seed from maple,walnut,alder and sycamore would require collections in southern Contra Costa or northern Alameda County since these species are found in low density within the project area. The seed should be properly labeled with date and collection location,and sent to a nursery for propagation.Care should be taken to avoid donor trees in the vicinity of landscape trees of the same species,since pollen contamination from the non-local landscape tree is likely. Seed may also be collected on-site from California wild rose,elderberry and Christmas berry.Seed and plants should be purchased or collected in nearby locations for the remaining species,which have limited seed sources.Seed for these species can be purchased from suppliers. In any seed collection,the donor plants should be monitored to determine when the seed is ripe.For many of the species in the plant palette,Table 4 shows its availability,through either purchase or local collection.Seed,cuttings and transplants may be collected on site,collected from off-site locations in southern Contra Costa or northern Alameda County,or purchased.For those species available for local collections,the propagule type and approximate time of year during which collections are made is provided. 6.29 Container Planting Techniques In ungraded areas,tree and shrub planting positions should be scalped clear of annual grasses and forbs in a circle centered on the planting site.These weeds would otherwise compete for moisture and sunlight critical to the establishing plants.The scalped area should be five feet in diameter for trees,and three feet in diameter for shrubs. Prior to planting,all exotic species should be eradicated within the area to be planted and the irrigation system should be installed,tested and fully functional. Tree and shrub planting holes should be augured prior to planting.Hole preparation promotes deep root penetration.Where soils are loose and well drained,auguring is not necessary. 110 I ` Planting holes should be dug to twice the depth and diameter of the plant container(Figure 24). The revegetation specialist may consider the option of using perforated ADS drain pipe vertically installed,to provide for deep watering of the root systems.If used,the drain pipe should be three inches in diameter,30 inches in length,in sound condition with no cracks,and filled with 3/4 inch drain rock,throughout the 30-inclidrain pipe column. A slow release fertilizer that will provide supplemental nutrients during the first two years should be used for all shrub and tree plantings with the exception of blackberry,cottonwood and willow cuttings. Two time-released fertilizer tablets should be used for each container planting hole.Seven gram 12:8:8 Agriform tablets or equal would be suitable.Application of additional fertilizers should not be necessary. Fertilizers,especially when applied in great quantities,tend to favor exotics. Backfill in the planting holes should consist of native soil.The revegetation specialist should review any plans to import soil for revegetation. On level ground,watering berms(two and one-half feet in diameter and four inches high)should be built around all container plants larger than liners.Berms around liners should be one and one-half feet in diameter and three inches high.These berms are needed to prevent water from running off,and they will settle and erode over time. Planting techniques on slopes differ slightly from plantings on level ground.To accommodate slope plantings,a small planting terrace is excavated approximately twenty inches wide and fifteen inches deep.The terrace is sloped slightly to the hill and a four inch berm is built on the open side to collect water. All trees and shrubs should be mulched with shredded nitrolized bark mulch,three inches deep and tapered away from the stem to avoid root rot.The deep mulch is expected to settle.Mulch inhibits weed growth,conserves soil moisture and is a preferred alternative to plastic weed cloths or chemical weed control. The day they are planted,all plants should be`watered-in',regardless of soil moisture conditions. Final planting plans should include specifications addressing inspection of site modifications, review and acceptance of planting stock,root and top pruning,handling and storage of stock,and acceptable planting dates. Optimal planting conditions are when the soil is moist to a depth of twelve inches,usually after the first fall rain.In a normal season,October is the preferred month.If drought conditions cannot be avoided,supplemental irrigation should be used to compensate.The physiological state of the plants is optimal during the fall and winter,therefore overall restoration success is • PACE 111 I� enhanced by adhering to appropriate planting schedules.In addition,a fall planting drastically reduces the need for supplemental irrigation. Section 6.30 Seeding Techniques Seeding with natives provides slope stabilization benefits as well as wildlife habitat.Areas to be seeded include:the flood plain terrace,bare areas between existing native vegetation,areas denuded of vegetation through exotics eradication and debris removal;and areas denuded through grading modification.The optimum season for direct seeding is fall,when moisture, temperatures and plant physiology are all favorable for establishment.If seeding with natives outside this biological window is conducted,reseeding may be required. Proper soil preparation is essential to seed establishment.Sites will be evaluated on a case-by- case basis by a revegetation specialist to determine appropriate procedures.The recommendations of the qualified soils scientist,described above,should be incorporated at this time.Soil preparation will include mitigation of compaction and creation of a suitable seed bed. Seed application alternatives include:broadcast seeding,broadcast seeding with straw,and hydromulching or hydroseeding.Seed is mixed with 200 lbs.of slow-release fertilizer(16-20-0) and applied via the appropriate method.A case can be made to exclude fertilizer if exotics are a threat to the establishing natives. If rapid soil stabilization is needed,a nurse crop is included in the seed mix.Plantain(Plantago insularis)is recommended as a nurse crop because it will not compete with the establishing natives and is non-persistent.Other nurse crop species could permanently establish in the community and become a maintenance problem. Establishment by broadcast seeding is primarily used for native grass and annual species.ltfthe fall,the soil should be scarified with a rake,after compaction is mitigated through other methods. Seed and fertilizer may be applied with hand-held spreaders to scarified soil,and the site should be raked so that approximately one eighth to one quarter inch of soil covers the seed. Broadcast seeding in the absence of straw should be used in small areas devoid of vegetation. No irrigation is required if adequate winter rains ensue. Broadcast seeding with straw mulching should be used in larger areas with moderate slopes(over 30 percent)to stabilize the slope and prevent soil crusting,which hinders germination.Prior to broadcasting the seed and fertilizer,the soil should be scarified with a rake,followed by raking to cover the seed with one eighth to one quarter inch of soil.Straw mulch is then applied by hand. Only certified weed-free straw should be used at a rate of 30 to 50 bales per acre. Straw will provide some protection against grazing by birds.Irrigation requirements should be determined on a case-by-case basis during final restoration planning. 112 Hydromulching differs from hydroseeding in that the mixture includes a wood fiber mulch. Hydromulching should be used in larger areas with steep slopes.The soil should be scarified,and the seed and mulch broadcast by hydraulic pumping.Irrigation requirements of seeded areas should be determined on a case-by-case basis during final restoration planning.If seeded at the proper time of year,no irrigation system should be needed.Hydromulching is significantly more expensive than broadcast seeding because hydraulic trucks and long hoses are needed to mix and apply the materials. Material specifications of a typical application of hydromulch for a restoration project on a per acre basis include:200 lbs.of a 16-20-0 slow-release fertilizer,1,800-2,000 lbs.of wood fiber mulch,150-200 lbs.of tackifier,30 to 50 lbs.of nurse crop seed,and brightly colored dye. Inclusion of the nurse crop may not be necessary if rapid seed germination is not needed.Final specifications should be prepared by an experienced revegetation specialist. Hydromulching specifications should address seed origins,seed pretreatment,fertilizers, materials specifications,materials handling and storage,certification and warranty period, contractor performance standards,cleaning of equipment prior to use and equipment specifications.The revegetation specialist should evaluate the merits of the two step hydromulching process,which is a California Department of Transportation standard.The process involves sprayingthe water and seed mix,followed by mulching.This places germinating seed closer to the soil and protects seed from drying out in the mulch. Seeding rates depend on seed weight,purity and germination.Perennial grasses grow slowly the first year and take approximately two years to establish a healthy stand.Direct seeding of large- seeded native grasses is generally adequate at a rate of 15 to 25 pounds per acre. Perennial grasses respond favorably to nitrogen fertilizers.On bare soil sites or sites relatively free of exotics,nitrogen may be applied during the first fall.If weed competition is anticipated to be a problem during establishment,nitrogen application should be postponed to the following season. Broadcast fertilizers should be applied only to bare soils along with planting or seeding.Since desired native plants will only uptake small amounts of fertilizer,rates should be appropriate to the establishing natives. 6.31 Transplanting Techniques Transplanting salvaged plants should be encouraged for appropriate species,such as wild cucumber(Marah fabaceous)and native rhizomatous grasses. Planting plans should include details of timing,collection,sizes,handling,storage,planting techniques and follow-up care. During construction,all undamaged.wild cucumber(Marah fabaceus)tubers excavated incidental to construction should be salvaged and stored so they can be replanted within the project area.Excavated tubers should be stored in the shade,and covered with soil and burlap which should be kept damp until they can be replanted.Storage may extend over three to four 113 I�� months,depending on the construction schedule.The tubers should be replanted in holes at least one foot in depth,covered with soil and left unirrigated.These planting holes should be located within the Zone 3 riparian area.Tubers should be planted at least 10 feet apart,and no closer than two feet to the next container plant.The number of wild cucumber tubers to be excavated is unknown,but all reasonable efforts to salvage them during construction should be made.The construction crew should be trained to look for them,and where and how to store them. Transplants of creeping wild rye should be collected in areas where they would otherwise be destroyed by construction activities.Plugs should be a minimum of four inches square and six inches deep,with the tops trimmed prior to digging.Salvaged plugs should be replanted the same day,if possible,or stored in a cool,moist place for a maximum of one day.The plugs should be thoroughly`watered-in'the day they are planted.Irrigation may be required to keep the transplanted plugs alive,especially through the first summer season.Plug transplantation should be conducted as soon as the fall ground is cool and wet. 6.32 Areas Expected to Naturally Revegetate Riparian vegetation is expected to naturally regenerate when cattle and horse grazing along the creek is discontinued. The freshwater marsh, willow and oak species will show the greatest response to this change in the management regime. Supplemental restoration plantings of these species however, may be locally beneficial, particularly when accompanied by exotics eradication. 6.33 Plant Protection Grazing will be reduced and eventually excluded from the riparian corridor and tributaries through the use of alternate watering sources and some exclusionary fencing,as well as zoning changes as described in the City of Dublin's Grazing Management Plan and the Specific Plan.Excluding cattle and horses from the creek and tributaries will make a significant contribution to natural restoration of riparian vegetation,and ultimately,habitat values. Protection of establishing vegetation or sensitive areas can be accomplished in a variety of ways, including educational signing,exclusionary fencing,and pedestrian unfriendly vegetation such as native blackberry or wild rose.The selection of the appropriate method will depend on the resource to be protected.Educational signing has obvious merits,but can unfortunately bring undesirable attention and noise to wildlife species that can interfere with breeding and care of young.Temporary fencing or flagging of plants may be required during critical establishment periods and at vulnerable locations.An inexpensive and effective fence can be constructed by stringing rope between posts,in conjunction with signing.Bright orange construction fencing is very effective.A signing and fencing plan should be prepared in the final planning phase. Native blackberry and rose thickets can be used to discourage people from entering sensitive resource areas.Vegetation intended to buffer or prohibit entry should be temporarily fenced until established. Plants should be protected from animals by caging only if deemed necessary by the revegetation specialist in the final planning phase.Oaks may require caging.The horticultural monitor or 114 revegetation specialist should be alert to excessive browsing. If damage is detected,cages can be retroactively fitted to plants.It should be remembered that browsing is a natural process and should only be discouraged if excessive.If used,cages require maintenance and eventual removal.Browsing can be reduced by appropriate watering,i.e.,not over watering. Gopher caging placed below ground should only be specified on replanting locations where the original plantings suffered extensive mortality due to gophers,or where root damage can be anticipated. Staking and guying of trees should be discouraged,especially in the riparian area.Exceptions include trees adjacent to trails.Those landscape trees requiring staking can be retrofitted once they demonstrate a need for staking to survive. Pests and diseases are a natural part of the ecosystem and should be evaluated on this basis by an experienced professional prior to prescribing any control treatments. Domestic animals,namely cats and dogs have detrimental effects on wildlife.The EIR for the Eastern Dublin Specific Plan describes enforcement of leash laws. 6.34 Temporary Irrigation System To accommodate the distinct water requirements of plants in the riparian restoration area and trail landscaping,two separate irrigation systems will be needed.The riparian plantings in the creek channel area are expected to become self-sufficient three to five years after planting, therefore a temporary irrigation system will be needed for these plantings.The trail landscaping, because of the distance to the water table,may require continued irrigation indefinitely and a permanent irrigation system should be installed if species used are not self-sustaining without it. No irrigation of the flood plain terrace should be installed,as it should be managed for non- irrigated native and non-native grasses. The irrigation system should be installed,flushed,tested and functional prior to the installation of the plants.Details of irrigation systems should be included in final restoration plans and should address:water point of connection(POC),adequate water pressure,lists of materials, sleeving,buried lines,staking lines and water quality.Groundwater pumping for irrigation should be avoided due to known water quality problems that will impair plant growth. In most cases irrigation should be supplied by drip systems.Irrigation of the riparian restoration area should be discontinued once the plants are established(approximately two to five years).If planted on native soils during dormancy,the plants are likely to require supplemental irrigation for only two or three seasons. Specifications for planting and installation of the irrigation system should include installation of drip emitters within the planting basin and placement of lines within the project area. 115 Small drip systems scattered along the creek can be run on battery or solar-operated timers to avoid the substantial cost of installing centralized systems. Duration and frequency of irrigation should be controlled by plant water demands and seasonally adjusted to reflect the plants'requirements.The California Irrigation Management Information System of Sacramento(C:I.M.I.S.)can be used as a source of information on regional watering requirements for various species.A maintenance manual that specifically addresses irrigation prescriptions should be developed in order to conservatively allocate water resources. 6.35 Salvage and Placement of Woody Debris Large woody debris that has fallen to the ground,such as tree trunks or large limbs play an important role in riparian and upland ecology.Insects,reptiles and amphibians use the woody debris for shelter and nesting habitat,downhill sediment movement is arrested by woody debris, and its eventual decomposition provides organic material for soils. Some trees may have to be removed during the construction of the project.Large(greater than six inches in diameter at the small end)limbs and trunks should be salvaged,bucked into 6-12 foot lengths and salvaged for placement on the upper banks,or at the top of the bank of the tributaries to Tassajara Creek.Flood control concerns restrict the placement of this woody debris in Tassajara Creek.Large woody debris needs to be firmly anchored in place to thwart any attempts to roll or move them into the flood control channel. Placement details should be developed as part of the final plans and specifications. 6.36 Horticultural Monitoring and Establishment Maintenance Horticultural monitoring will be conducted as part of permit requirements established by the California Department of Fish and Game,the Army Corps of Engineers,and the State Water Quality Control Board.The purpose of the horticultural monitoring program is to establish diverse riparian vegetation within a relatively short period of time,so that the habitat can subsequently sustain itself in perpetuity.The establishment maintenance period of riparian projects in northern California typically requires three to five years.The habitat monitoring program is different in that it focuses on quantitative measurement of the vegetation development,as discussed below. Horticultural monitoring and maintenance should evaluate and trigger remedial actions regarding:cause and replacement of mortality,addition of or removal of plant cages,biological and mechanical erosion control,debris removal,exotic plant eradication,irrigation,species cultural requirements and treatments,replanting,vandalism repair,protective fencing and signing.Strict adherence to irrigation and weeding guidelines prepared by the revegetation specialist will be essential for restoration success.Many restoration failures are explained by inadequate weeding,and/or excessive and frequent irrigation.The revegetation specialist will identify any horticultural or other problems. 116 Horticultural monitoring,sometimes referred to as site monitoring,is necessary to evaluate plant health and to identify and correct problem areas.It is a subjective process and relies on the environmental horticultural expertise of experienced restorationists.If a maintenance contractor is responsible for establishment maintenance,frequent review by the revegetation specialist is recommended,starting with overseeing site preparation and installation,and continuing through the establishment period. Because revegetation may be fragmented by phasing with different owners involved in the distinct phases,it is recommended that a maintenance manual be developed prior to plant installation.A manual would detail the maintenance procedures and identify the cultural requirements of the dominant species. To ensure that subsequent project phases benefit from earlier restoration efforts,the maintenance manual should be designed to accommodate updating. Erosion control will influence maintenance activities until the plants are well established and thriving without artificial irrigation.The revegetation specialist should evaluate local failures and recommend appropriate remedial actions.In most cases,the area will simply require minor repairs and revegetation.Severe problems may dictate an engineering solution.Erosion failures should be evaluated on a case-by-case basis. Common erosion problems of revegetation projects that may be anticipated include:gullies,rill and sheet erosion,and bare soil areas.Repair typically includes redirection or dissipation of the water source,and recontouring of soil,followed by seeding,mulching,or planting. If appropriate,the revegetation specialist will prescribe seeding of eroded areas.The plant palette and installation guidelines employed in the revegetation phase should dictate species selection. The use of invasive exotic species should be avoided.Plantago insularis,although not native,is recommended as a nurse crop for most erosion control situations.As a nurse crop,it establishes quickly to stabilize soil but will not compete with the native plants. Removal of trash and litter should be done by hand on a regular basis. A desirable objective is to remove all exotics prior to planting.This gives the natives the competitive edge needed to compete with exotics and capture the site.Freshly graded soil from site preparation provides a perfect seedbed for windblown seed from invasive exotic species.The success of initial eradication efforts will determine maintenance requirements. A desirable maintenance goal is to remove exotics before they are allowed to seed or become well established on the site.Invasion of the restoration areas by exotic species should be noted in the monitoring reports and prescriptions for removal should be provided.Exotic eradication 117 ).5 /. .., , • during the maintenance period should emphasize hand removal techniques.Native vegetation should be protected and most exotic seedlings are readily removed by hand. If used,chemicals should be strictly regulated.The site preparation guidelines provide specific control treatments for the dominant exotic species,but the maintenance manual should identify manual techniques for exotic seedlings.Conservative application of chemicals is discussed in a previous section. Irrigation should be provided in such a manner as to facilitate proper root development.The maintenance goal is to ensure that plants become established so they are independent of the need for supplemental irrigation after the establishment period.This goal requires that plants develop extensive root systems that are able to tap groundwater supplies throughout the dry summer months.The use of deep,infrequent waterings stimulate the plants to develop the extensive root systems required to meet this goal.If the plants are overwatered,or receive frequent shallow irrigation,there is no incentive for the plants to develop extensive root systems and their roots will remain at the surface. The maintenance manual should detail specific irrigation prescriptions that are based on the species,time of planting,method of application and the need to develop deep root systems for plant establishment. All temporary irrigation systems should be maintained in a fully functional condition for approximately five years,regardless.of whether the system is still in use.The plants may require supplemental irrigation in unusually harsh conditions during this period.Irrigation may cease once the revegetation specialist has determined that the vegetation is self-sustaining.If properly maintained,temporary irrigation systems may be moved to subsequent project phases after five years.To ensure that the vegetation is self-sustaining in the absence of irrigation,the site should be monitored for an addition two years after the irrigation is turned off. The irrigation system should be monitored and repaired on a monthly basis to ensure that all plants receive adequate water.Early morning irrigation is required under windy conditions.In addition,all plants should be monitored for stress and desiccation. It is strongly advised that maintenance staff use,but not rely on timers,and remain on-site during irrigation to identify problems.It is critical that staff inspect the plantings frequently to insure that the irrigation regime is adjusted to reflect changing conditions,and that the system is functioning as designed. Oaks are particularly susceptible to root disease,and overwatering can promote disease,since these species are adapted to dryer conditions.In addition,excessive irrigation promotes unwanted weeds that must then be eradicated.The revegetation specialist should be consulted after several fall rains have occurred,to determine if the irrigation can be discontinued until spring.Established oaks should not be irrigated during summer months. Cultural treatments such as fertilization and pest control should be kept to a minimum.It may be necessary to measure certain site conditions such as soil moisture or weather,in order to determine cultural treatments. Fertilizers should not be necessary,aside from what is administered at plant installation.No herbicides or pesticides should be allowed to contact open water,or runoff into the creek.The use of chemicals in treatment of pests will be restricted. Common pests and disease that occur naturally in the environment(such as Anthracnose on native sycamore trees)should be identified as tolerated infestations.Problems that threaten plant health and vigor should also be identified,and recommended treatment alternatives should be included. Integrated pest management should be considered to control problems that threaten plant health and vigor. No maintenance is required after the establishment period,except to maintain trails and view conditions. Large branches in Tassajara Creek that have the potential to clog downstream culverts may be removed.Large woody debris however,is beneficial to certain amphibian and insect species,and the treatment of such material is described above in the section on large woody debris. The specific cultural requirements of the tree and understory species should be provided in the maintenance manual. During the initial revegetation phase,signs should be posted at all possible access points to prohibit entry or trespass.Fencing may also be necessary.Signs should identify areas as sensitive and under restoration. Vegetation intended to provide a buffer or prohibit entry should be fenced until firmly established. The revegetation specialist will prescribe replanting requirements,including any species substitutions,numbers and schedules.An inspection should be made six times per year during the first year after installation.Thereafter,mortality and plant growth and vigor should be checked a minimum of two times per year until performance standards and establishment goals are achieved.Table 6 shows the monitoring schedule for the horticultural evaluations and the quantitative data collection(habitat monitoring).Horticultural visits should be timed to span the entire year,to evaluate plantings after a large storm event or an especially hot spell during the summer. = 119 l -!. The flood plain terrace located above the riparian corridor should be managed to support non- irrigated native,annual grasses and some wildflowers.If the site is properly prepared to support establishment of the seed mix and seed is applied at the correct time of year,maintenance to establish the terrace should focus on erosion control and control of especially noxious weeds. Non-native grasses,although not included in the seed mix,are expected to invade these areas and should be tolerated as part of the natural-system.Long-term maintenance of the grasses should emphasize control methods such as mowing twice per year.Mowing encourages the native grasses and discourages the yellow star thistle and other noxious weeds,while controlling fuel loads.Disking is not preferred because it favors exotics and promotes soil erosions. 6.37 Habitat Monitoring Habitat monitoring will be conducted as part of permit requirements established by the California Department of Fish and Game,the Army Corps of Engineers,and the State Water Quality Control Board.A habitat monitoring program is designed to quantify and document establishment of the vegetation and determine at what point the habitat is self-sustaining. Quantitative monitoring df restoration or mitigation areas should be conducted for five years,or when all performance standards have been met,to ensure establishment of the restoration plantings.It should be conducted at a minimum of two times during the first year,and once per year annually thereafter.A qualified monitor should measure and evaluate survival and native plant health and vigor.Performance standards should focus on survival,growth and vigor, demonstrated self-sustaining vegetation,and implementation of remedial actions.Growth and vigor,typically measured quantitatively through a rating system,should demonstrate a trend towards healthy establishment.Tree and shrub survival within five years should be at least 85%in the fifth year.In order for vegetation to demonstrate that it is self-sustaining in the absence of irrigation,the site should be monitored for an addition two years after the irrigation is turned off. Remedial actions should have been implemented in a timely fashion. If a large area of planting is undertaken,representative plots that will result in statistically representative sampling may be used to reduce monitoring efforts. • Monitoring methods,specifically sampling techniques,should be designed and conducted by a qualified biologist.Methodology should remain uniform throughout the study to avoid inconsistencies which may jeopardize the usefulness of the analysis. Mitigation monitoring parameters may be further defined by regulating agencies and may include:cover,composition,and plant vigor.Permitting agencies may require additional performance standards(such as 80 percent cover within three years). Annual reports summarizing monitoring methodology,findings and analysis should be submitted to the resource agencies for evaluation. Table 6 shows the monitoring schedule for the habitat monitoring visits.Quantitative data collection should occur in the spring and in the fall.If the data is collected the same month of the 120 year,from year to year,the analysis will be more meaningful The horticultural and habitat monitoring visits can be scheduled to coincide. 6.38 Wildlife Surveys In the stream corridor,there is no obvious need for wildlife surveys as part of the restoration program,unless required by regulatory agencies as part of a mitigation plan.Substantial information developed from reconnaissance and focused surveys prior to and during the EIR process is available. If an interpretation program is developed,surveys of avian species could provide detailed information about the inhabitants of the stream corridor. • 6.39 Long-Term Management of Habitat Once established,the riparian vegetation will mature and unique plant associations will evolve over time.Because periodic flooding of Tassajara Creek is inherent in the restoration design, rejuvenation of these stands over the long-term will occur.Flood scouring,soil preparation and seed dispersal are the means to achieve rejuvenation of decrepit stands. 13a 121 Table 6. Monitoring Schedule Restoration or Horticultural Monitoring Habitat Monitoring Annual Report Contingency Revegetation Area Frequency-Sampling Entire Frequency-Sampling Measures/Remedial Actions Area Representative Plots Riparian Restoration and During Installation Baseline Data in Year 1 Years 1-5 Replace mortality,control Mitigation Areas exotics,seed at discretion of 6 times in Year 1 Spring and Fall in Year 1 Spring and Fall Years 2-5 Fall in Years 2-5 monitor,repair fences,repair erosion,and other measures at the discretion of the monitor. Flood Plain Terrace During Installation None None Control erosion,control Four times in Year 1 noxious exotics,seed at One time in Years 2-5 discretion of monitor,repair fences,and other measures at the discretion of the monitor. 122 IMPLEMENTATION 7.0 IMPLEMENTATION 7.1 Implementation and Management The Eastern Dublin Specific Plan specifies that the City of Dublin will establish a mechanism for the ownership,management and maintenance of the stream corridor prior to final map approvals. Improvements will include stream corridor restoration,flood control improvements and trail construction to enhance and access the open space network.Though the improvements may be • phased in a number of configurations based on ownership patterns and scheduling,phasing by the creek reaches would ensure comprehensive treatment and ease the transition between the reaches.A suggested preferred phasing might be first the lower reach,the middle reach and then the upper reach.In any event,applicants should demonstrate to the City of Dublin and Zone 7 how the proposed improvements will transition and interface to adjacent properties along the corridor. The involved agencies,such as Zone 7 and East Bay Regional Park District may have some funding earmarked for flood control and trail improvements proposed along the Tassajara Creek corridor.The City of Dublin Parks and Recreation Master Plan describes funding mechanisms for acquisition,capital improvements and operations.It also discusses potential cooperative and city funding sources as well as regulatory mechanisms including:land dedication,in-lieu fees, user fees,grants,cooperative agreements,bond and tax measures,donations,transfer of ownership,foundations,land acquisition and development,landscape lighting districts,special assessment districts,Mello Roos districts,open space and conservation easements,transfer of development rights,restrictive covenants,performance and specialty zoning and planned unit development. . The Fnctern Dublin Specific Plan addresses implementation and phasing issues of the stream restoration program.The City of Dublin's review process for development projects along the stream corridor may provide for stream corridor land dedication and related improvements(i.e. flood control modifications,trails,roads,revegetation,landscaping,etc.)as a condition of project approval.To realize the goals of the comprehensive stream restoration program,the stream portions of the Specific Plan study area should not be fragmented from adjacent development during the planning and review process. Development plans along the stream corridor should also be reviewed by East Bay Regional Parks District,Zone 7 and California Department of Fish and Game.In addition,appropriate regulatory agencies should review and comment on plans as part of their agency's permitting process.Early involvement of the permitting agencies in project design review is strongly encouraged. Environmental permits are discussed in a separate section below. 123 • Preferably,special maintenance of flood control facilities within the stream corridor would be handled by Zone 7.Special maintenance of regional trail facilities within the stream corridor should be handled by East Bay Regional Park District.Ownership of the stream corridor should be dedicated to a public agency and consistent over all three reaches.Long-term maintenance and management will be accomplished through the development of cooperative institutional agreements for which complementary management goals and activities will be agreed upon and jointly financed by participating agencies,including the City of Dublin,East Bay Regional Park District and Zone 7.Long-term maintenance and management guidelines should be developed and enforced to ensure that the policies of the Specific Plan and these guidelines for the stream corridor restoration and preservation are continued by the maintenance agencies. 7.2 Regulatory Compliance Applicants will be required to comply with federal,state and local environmental regulations. Early applicant consultation with permitting agencies during the design process is strongly encouraged.Applicants to the City of Dublin should demonstrate consultation with regulatory agencies and compliance with environmental permits.Permits in the Tassajara Creek stream corridor relate to wetlands,erosion and water quality. Wetlands fall under the jurisdiction of several regulatory agencies and impacts to wetlands might require federal,state,and/or local permits or agreements.Prior to the issuance of any construction permit for actions likely to result in impacts to potential wetlands onsite,the principle actions would include: • Army Corps of Engineers Clean Water Act Permit • California Department of Fish and Game Consultation • State Water Quality Control Board Certification or Waiver 7.2.1 Army Corps of Engineers The Army Corps of Engineers(ACOE)has jurisdiction over a variety of habitats,including wetlands and waters of the U.S.that occur within the City of Dublin.Under Section 404 of the Clean Water Act,wetlands are defined as those areas inundated or saturated by surface or ground water at a frequency and duration sufficient to support and under normal circumstances do support a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps,marshes,bogs and similar areas,as well as seasonal wetlands that are only inundated for at least a specified time period during each year,defined by a percent of the growing season(12.5%of the 250-day growing season),which may vary with site conditions.To be classified as a wetland,a site must meet wetland soils,vegetation and hydrology parameters as defined in the 1987 manual.Waters of the U.S.include navigable waters,waters of the U.S.subject to ebb and flow of the tide susceptible to interstate commerce, 124 impoundments of waters,tributaries of waters,isolated waters,springs,intrastate lakes,rivers, streams,mudflats,sandflats,wetlands,sloughs,prairie potholes,wet meadows,playa lakes, natural ponds,and territorial seas that the use,degradation,or destruction of could affect interstate foreign commerce. Projects that include potential dredge or fill impacts to waters of the U.S.and adjacent wetlands must be reviewed by the Army Corps of Engineers pursuant to§404 of the Clean Water Act of 1972.Activities that require a notification or a permit from the Army Corps of Engineers include discharge of dredge or fill material,excavation and disposal activities in waters of the U.S. Aggregate wetland impacts(defined as direct fill or indirect effects of fill)of less than one acre do not require an Individual 404 Permit.Certain activities in wetlands or"waters"are automatically authorized,or granted a General Permit which allows the filling of wetlands where impacts do not exceed one acre.The Army Corps of Engineers assumes discretionary jurisdiction over proposed impacts which total between one and ten acres.In such cases,the Army Corps of Engineers can issue either a Nationwide or an Individual Permit.The Army Corps of Engineers has mandatory jurisdiction over proposed impacts of ten acres or more(i.e.,an Individual Permit would be automatically required). Projects which require less than one acre of fill of wetlands or waters of the U.S.and which meet the conditions of the permit would be expected to qualify for a general or Nationwide permit. The need for mitigation and monitoring is determined by the specific type of permit required. Once a development plan has been developed,notification should be made to the Army Corps of Engineers district office in San Francisco,in accordance with§330.7(Notification Procedures) of the Corps of Engineers Regulatory Program Regulations and a jurisdictional determination requested.Such notification should include the name,address,and phone number of the - applicant,a brief description of the proposed work,its purpose,a formal delineation of the wetlands/waters of the U.S.onsite,the total acreage of jurisdictional habitat to be affected,and a conceptual outline of mitigation measures,if required.Upon receipt of this notification,the Army Corps of Engineers has 15 days to issue a public notice to other interested agencies and local interest groups.The comment period typically lasts 15-30 days,depending on the nature of the proposed activity.The Army Corps of Engineers will consider all comments and consult with other federal agencies,if appropriate.The District Engineer may ask the applicant to provide additional information or data before making his or her final decision on whether or not to issue a permit.Prior to the issuance of a Nationwide permit by the Army Corps of Engineers,the applicant is required to obtain a water quality certification or waiver from the Regional Water Quality Control Board(see below). . 125 The Army Corps of Engineers Individual and Nationwide permitting process relies upon input from other state and federal agencies,including the U.S.Fish and Wildlife Service for protection of federally listed plant and wildlife species,the State Historic Preservation Office for protection of historic structures,the local office of the Regional Water Quality Control Board for issuance of a waiver or certification for the proposed project,and the California Department of Fish and Game for protection of state-listed plant and wildlife species.The Nationwide permit is not valid unless all appropriate agencies have been notified and a water quality certification or waiver is secured. 7.2.2 California Department of Fish and Game The California Department of Fish and Game has jurisdiction over plant and animal species recognized by the California Fish and Game Commission as rare,threatened or endangered(RTE species)as well as wetland habitats and its commenting authority over CEQA documents.CEQA requires mitigation measures for significant impacts and California Department of Fish and Game is the state agency responsible for impacts to plant,fish and wildlife resources.It should be noted however,that many actions that produce impacts to creeks and drainages,and the resources dependent upon them are not subject to any discretionary action under CEQA or any other regulation. Wetland Impacts Regulation The Fish and Game Commission,in recognizing that wetlands provide significant and essential habitat for a wide variety of important resident and migratory fish and wildlife species,has clarified its policy to protect,preserve,restore,enhance,and expand wetland habitat in California.Furthermore,it is the policy of the Commission to strongly discourage development in,or conversion of wetlands.The Commission therefore opposes wetland development proposals unless,at a minimum,project mitigation assures there will be "no net loss"of either wetland habitat values or acreage. The California Department of Fish and Game normally comments on any proposed actions resulting in significant direct impacts to biological resources through the CEQA review process, when issuing a Streambed Alteration Agreement(described below),and when reviewing during the Water Quality Control Board Certification or Waiver process(as part of the 404 permitting by the Army Corps of Engineers,described below).When a specific project is proposed, mitigation measures for impacts to wetlands should be included as part of the project.In order of preference,the regulatory agencies recommend the following types of mitigation:1)avoidance of impacts through project redesign and/or relocation,2)minimization of impacts,and 3) compensation for resource losses. In order of preference,compensation(widely referred to as "mitigation")would include 1)onsite in-kind replacement of habitat,2)offsite in-kind replacement,and 3)mitigation banking. 126 1 L711 1601-3 Streambed Alteration Agreement The other instrument by which California Department of Fish and Game has regulatory oversight for actions which might result in impacts to the state's plant and wildlife resources is via the requirement for a 1601-3 Streambed Alteration Agreement for any project that will substantially divert or obstruct a stream,change the bed, channel or bank,change the natural flow,or use any material from the streambeds.Plans will again be reviewed for compliance with the Department's standard for a 100 foot setback.The Department has a no-net-loss wetland policy,hence requiring mitigation for affected wetlands. Securing the 1600 Agreement requires consultation with California Department of Fish and Game staff,completion of an application and fee,and preparation of mitigation requirements if impacts are unavoidable.Monitoring may be required if mitigation is a condition of the agreement.Unlike the Army Corps of Engineers,California Department of Fish and Game may require mitigation for impacts to jurisdictional habitats of less than one acre.For example,if removal of riparian vegetation for a stream crossing is unavoidable,California Department of Fish and Game will typically require the replacement of riparian species at a 3:1 ratio,and mitigation of habitat area at a minimum of 1:1 ratio.The fee for the Streambed Alteration Agreement is based upon the value of the improvements made in the project.No public review is provided for in the 1601-3 Agreement process and it is important to note that California Department of Fish and Game does not have the discretion to deny an application for a Streambed Alteration Agreement if all the requirements for the Agreement have been met. 7.2.3 State Historic Preservation Office The State Historic Preservation Office(SHPO)has authority over historic properties.Projects which require CEQA documentation or permitting by the Army Corps of Engineers trigger oversight by SHPO.SHPO makes a determination on whether historic properties occur within a proposed project area.The project applicant directs correspondence to SHPO via the appropriate Information Center to determine whether historic properties occur within the project area.For projects in Dublin,inquiries would be made to the Information Center at Sonoma State University.If no historic properties occur within the project area,a letter to that effect is sent to the permitting agency by the Information Center.If historic properties do occur within the project area,the Information Center will send a letter describing the historic properties and requirements for mitigating impacts to the property.SHPO should be notified by the project applicant when submitting a permit application or notification to the Army Corps of Engineers. 7.2.4 State Water Quality Control Board Certification Pursuant to§401 of the Clean Water Act,any applicant for a federal permit to conduct any activity which may result in any discharge into navigable waters must provide a certification or waiver from the California Regional Water Quality Control Board(RWQCB)that such discharge will comply with the Clean Water Act(RWQCB,1988).Projects that would result in discharges into waters of the U.S.,but qualify for certain Nationwide Permits also require state water quality 127 certification or waiver.The Water Quality Control Board has a no-net-loss wetland policy in effect,and in recent years the Board is enforcing this policy,i.e.requiring mitigation for all impacts. Upon receipt of notification from the applicant,the Army Corps of Engineers might issue a public notice for review.However,a separate application should be made directly to the Bay Area Regional Water Quality Control Board by the applicant.The application includes a project description,quantification of jurisdictional impacts,mitigation and monitoring plans as appropriate,site maps and a fee.If the Board fails or refuses to act on certification requirements within a reasonable time(e.g.,60 days after receipt of notification from the Army Corps of Engineers),the certification requirement is waived and the proposed action may proceed without conditions.The Board may elect to issue a waiver.If the Board issues a water quality certification which includes special conditions,the District Engineer will add these conditions to the Permit.The fee for the certification or waiver is$500. 7.2.5 Regional Water Quality Control Board-NPDES and Reclaimed Water Permits For any development exceeding five acres,a National Pollutant Discharge Elimination System (NPDES)permit is required from the Regional Water Quality Control Board.The City of Dublin,in turn,will require the state permit prior to issuing approval of grading and improvement plans. However,all developments regardless of size,require the approval of the City of Dublin Public Works Department,which requires erosion control and the installation of Best Management Practices(BMPs).Any development should expect to use approved BMPs both during construction and as a permanent part of the development infrastructure.The BMPs are planned in the preparation of the project's Storm Water Pollution Prevention Plan(SWPPP), which must be approved by the City of Dublin prior to the start of construction.Among the requirements established by the City of Dublin Ordinance No.52-87,Establishing Requirements for Protection of Watercourses,is that a written permit is required prior to discharging into or connecting any pipe or channel to a watercourse;depositing,planting or removing materials from a watercourse including its banks;altering any structure in a watercourse;and causing flow to be diverted. The Regional Water Quality Control Board may also require permits of the application of reclaimed water.Zone 7 is also involved in the review process. 128 APPENDIX A REVEGETATION SCHEDULE Reveget-,tion Schedule — Scheduling of Project Tasks and Components Task. PLANNING PHASE Project Management Preparation of Preliminary Mitigation Plan Detailed Analysis of Site Conditions Land Acquistion (for Mitigation) Preparation of Final Mitigation Plan Permitting (Mitigation Plan Component Only) Components Administration Coordination Progress Reports Project Description Mitigation Goals and Objectives Final Success Criteria Proposed Mitigation Sites Implementation Plan Establishment Period Maintenance Monitoring Program Air Photos _ Surveying Monitoring Program Design Soil Sampling Monitoring Well Installation Substrate Analysis Groundwater (Piezometer) Monitoring Slope and Aspect Analysis Hydrologic Analysis Project Description Mitigation Goals and Objectives Final Success Criteria Proposed Mitigation Sites Implementation Plan Establishment Period Maintenance Monitoring Program COE COE 4 Permit USFWS Coordination RWQCB Permit CDF&G 1601-03 Permit EPA Coordination _ County city — Commissions Page 1 �a�ua.-ez Task i Year Year � i ear I ear ear Year Components: -6 I -S., ( I -3 -2 r , ear ; ea i ear ear Year. ear j i Preparation of Bid Documents -4 WISPISu1 F i WISpISuI F I W' - ;SplSui F'WISpISuI FiWiSp1Su; F W-Sp;Su; F rading and fearing Plan I +3 Fi - Sul F W;Sp Sul FIW•I�� WiSoSul F;WISPSuI FiW SpISu F!W�Sp;Sul (Habitat Mitigation Components - i I including Native Plant Protection) � it`�e Preparation, Exotic Eradication and Phase I Revegetation (Groundco ter) and I �; Erosion Control Installation Plans and i Contract Soecifications I Ilrrigation System Design I; I :: I G I::: I•:>. i. I I I:.;_:: Phase II Revegetation (Woody Plant) ::: Installation Plans and Contract Specifications Construction SchedulingSequencing of Work eq k Components 9 P -«- (Revegetation) oordination with Nurseries for Custom t Seed and Plant Collection and PI P a anon Coordination with Engineers oordination with other Contractors ::.:: and d Suppliers r • Experimental Testing or Pilot Projects _.. t MP LEM ENTATI ON PHASE _ Project Management 9 Administration - stration »� ` �� Coordination atio n I I I Progress Reports P I . .. t Preparation SieP �(Rough) _ I ( 9) Grading/Drainage Native ati e Plan Protection I t ��• Plant I Protection Site Inspection Non -organic Den IDebris Removal _ .;::: ..... Ve etative Material ate ial 9 g mo al IChippinglStorage of Mulch i Salvage/Storage of Logs Iv Sa a e/Stock ilin of Topsoil I I Weed Control in Stockpiled Topsoil • Preplanting Weed Control Exotic P t c Plant Control/Removal Ia>.. Pest Control Ripping and Discing I '>: Soil Scarification I>` i Addition of Soil Amendments Import Topsoil L Placement of Topsoil Final (Finish) Grading/Drainage Grading Site Inspection I:.. I� Revegetation p o Reve etatin Site Inspection f''k9e 2 Task Erosion Control and BankjSlope Protection Fencing of Revegetation Sites Plant Procurement - Groundcovers Woody Plant Materials _ Irrigation System - Woody Plants Plant Installation and Plant Protection - Groundcovers Plant installation and Plant Protection - Woody urchase/Fabrication of Plant Protect on Construction of Watering Basins installation of Plant Protection P urc se of urchase of Mulch installation of Mulch Revegetation Site Inspection Documentation of As -built Condition SPI 7,77 MAN 77 o Xq Task Components.. MAINTENANCE AND MONITORING PHASE Irrigation I Cost of Irrigation Water (Irrigation System Inspection Irrigation System Maintenance Documentation of Irrigation Plant Maintenance and Weed Control lWeed Control Repair of Watering Basins Fertilizing Pruning Repair of Plant Protection Other Browse (Herbivore) Protection Insect Pest Control rs_uppIemental Planting Removal of Plant Protection Maintenance Inspections and Recor Keeping Erosion Control Erosion Control Inspection(s) Ongoing Maintenance Remedial Action Site Protection and Maintenance On -going Surveillance/Patrols Maintenance of Protective Fencing Maintenance of Signing Maintenance of Access Exotic Plant Eradication Debris Removal Establishment Period Monitoring Long -Term Maintenance Long -Term Monitoring AB3180 Monitoring Y ear -6 W I SID, Su ear -- Year: Year. Year i _Year eat Year Year -5 j -4 -3 -2 _J +1. +2 , +3 I.. a1S F W.ISpISuI F Y!SolSul FiWISo;Sul F!WISpISu, F W;SpiSui FiSPjSui F WISpISui F;WI r I Soil/Site Conditions Groundwater Monitoring Reconnaissance Surveys r Monitoring of Plant Survival and Growth Photodocumentation of Results Reporting I Preparation of Maintenance Manual € t Training of Maintenance Staff_ Monitoring of Vegetative Characters] Habitat Features Monitoring of Wildlife Populations Photodocumentation, Reporting Monitoring of Mitigation Measures Reporting ' (See Implemenation Phase for Cost of Plant Materials) C. f f. f Page 4 1 7 agar—az APPENDIX B SPECIAL SUBMITTAL REQUIREMENTS CITY OF DUBLIN CHECKLIST OF SPECIAL SUBMITTAL REQUIREMENTS FOR PD REZONE HYDROLOGY AND HYDRAULICS FOR PROJECTS ADJACENT TO TASSAJARA CREEK AND ITS TRIBUTARIES Note:This submittal checklist is intended to supplement the City of Dublin's Checklist of Submittal Requirements for PD Rezone.Items already included in the City's current checklists are not repeated in these Special Submittal Requirements.The special submittal items are arranged by the title of the submittal.This checklist is intended to assist applicants in the preparation of submittal documents relating to the stream corridor, and to facilitate the City's project review process.Submittal documents can draw from the information and guidelines set forth in the Eastern Dublin Comprehensive Stream Restoration Program(hereinafter referred to as the Stream Restoration Program,or SRP). References to the Stream Restoration Program are made by section number.The requirements for each parcel should be determined on a case-by-case basis and will depend on the location,site conditions and proposed improvements.It will be the responsibility of the applicant to work closely with City staff and other regulatory agencies to determine which documents should be prepared. On a case-by-case basis,a City Planner will place a checkmark next to the information required for submittal.The City Planner will need to coordinate certain submittals,such as hydrologic analysis with the Department of Public Works.Applicants may consider cooperating with adjoining owners for some of the following studies. Topographic Map A Topographic Map of the Tassajara Creek corridor(extending 150 feet beyond the top of bank on both sides of the channel,including applicable tributaries)is required.It also forms the basis for HEC-2(or HEC-RAS)modeling,development of a channel slope profile,mapping hydrologic and other setbacks,and grading.Since the channel is often narrow and the map will be used as a base map for detailed planning,the scale should be no less than 1"=40'and a contour interval of no less than five feet.The map will provide adequate contour detail to clearly show the location of the creek center line,top of bank for low flow line,top of bank for flood plain,and toe of bank for flood plain.The map will delineate areas of slope bank instability,areas of existing erosion and erosion potential,and the type and extent of existing man-made improvements including stream crossings,drop structures,bank stabilization treatments,rubble,etc.(see SRP sections 4.1,4.6) Flood Control Modeling HEC-1 modeling will be required or existing flood flow data will be provided by the City of Dublin or Zone 7 of the Alameda County Flood Control and Water Conservation District(Zone 7)to serve as the basis for the flows utilized in HEC-2 flood conveyance modeling.(see SRP sections 4.1,4.2,4.6) G HEC-2 modeling of existing conditions of the reach being developed(and adjacent reaches)is required by the City of Dublin and Zone 7. The model is especially detailed where there are bends,bridges,channel narrowing,or other elements which tend to constrict or expand the flow,where there are low banks over which a flood may spill onto adjoining lands,or other locations as requested by the City of Dublin or Zone 7. The model is used to evaluate flood conveyance capacity and rates of flow under various hydrologic conditions so as to pinpoint reaches of concern and the degree of the existing problem.(see SRP sections 4.1,4.2,4.6) HEC-2 modeling of post-development conditions of the reach being developed(and adjacent reaches)is required by the City of Dublin and Zone 7.The model requires detailed topographic information of the channel with frequent cross-sections at,above and below areas of constriction;typical reaches;and other locations as requested by the City of Dublin or Zone 7.The model is used to evaluate flood conveyance capacity and rates of flow under various hydrologic conditions.The key function of the channel is to be able to contain and convey flood flows up to and including the 100-year design flood. The applicant needs to develop a concept of what channel alterations are appropriate to meet flood.conveyance,public access,safety,aesthetic,and restoration objectives in order to create an appropriate HEC-2 model.This may be a several step reiterative process involving repeated consultations and communications with the concerned agencies. Reaches of the stream corridor being considered for ownership by Zone 7 will need to be made to conform to the requirements for the character and dimensions of the channel as specified in the Alameda County Flood Control and Water Conservation District's Hydrology and Hydraulic Criteria Summary for Western Alameda County. Some aspects of the design in the area being considered for ownership by Zone 7, particularly aspects related to habitat and aesthetics,may need to be negotiated with and between the City of Dublin,Zone 7,and the California Department of Fish and Game. (see SRP sections 3.1.1,3.1.3,4.1,4.2,4.6) Channel Stability Study A Channel Stability Study of Tassajara Creek is a likely requirement of either the City of Dublin or Zone 7 to demonstrate the inherent stability of the overall channel. A preliminary study has indicated that this may be a problem in several reaches.A detailed analysis of the channel slope and bankfull discharge will likely be required to determine if the Tassajara Creek channel can be altered safely.Other conditions of approval may result from this study.Note,that should channel alteration be approved,geotechnical studies of Streambed and bank materials will be required to ascertain the need for and placement of erosion protection measures.(see SRP sections 3.1.3,4.4,4.6) For help in understanding this information,please contact: PLANNING DEPARTMENT STAFF CITY OF DUBLIN 100 CIVIC PLAZA DUBLIN,CA 94568 (510)833-6610 2 CITY OF DUBLIN CHECKLIST OF SPECIAL SUBMITTAL REQUIREMENTS FOR TENTATIVE AND FINAL SUBDIVISION MAP FOR PROJECTS ADJACENT TO TASSAJARA CREEK AND ITS TRIBUTARIES Note:This submittal checklist is intended to supplement the City of Dublin's Checklist of Submittal Requirements for Tentative Subdivision Map(T.Map).Items already included in the City's current checklists are not repeated in these Special Submittal Requirements.The special submittal items are arranged by the title of the submittal,and may be included in Item 12 Special Information of the T.Map Submittal Requirements.This checklist is intended to assist applicants in the preparation of submittal documents relating to the stream corridor,and to facilitate the City's project review process.Submittal documents can draw from the information and guidelines set forth in the Eastern Dublin Comprehensive Stream Restoration Program (hereinafter referred to the Stream Restoration Program,or SRP).References to the Stream Restoration Program are made by section number.The requirements for each parcel should be determined on a case-by-case basis and will depend on the location,site conditions and proposed improvements.It will be the responsibility of the applicant to work closely with City staff and other regulatory agencies to determine which documents should be prepared. On a case-by-case basis,a City Planner will place a checkmark next to the information required for submittal.The City Planner will need to coordinate certain submittals,such as hydrologic analysis with the Department of Public Works. Written Statement(TENTATIVE AND FINAL MAP) A Written Statement that the proposed application is consistent with the Eastern Dublin Comprehensive Stream Restoration Program is required. Tentative Map(TENTATIVE AND FINAL MAP) Existing Topography and Improvements should show the location of the creek center line,top of bank for the low flow line,top of bank for the flood plain,and toe of bank for the flood plain. Areas of slope bank instability and areas of existing erosion and erosion potential should be delineated.The location,type and extent of existing man made improvements,including stream crossings,drop structures,bank stabilization treatments,rubble,etc.should be delineated.(see SRP sections 3.4,4.1,4.6,6.16) Locations and descriptions of significant habitat features such as wetlands,tributaries,aquatic habitat,riparian habitat,large stands of exotics,wildlife nests or significant wildlife habitats,and unique conditions that constrain the site should be shown.The locations and descriptions of these features should be prepared by a qualified biologist.(see SRP sections 6.2,6.5,6.6,6.19) Proposed Improvements(TENTATIVE AND FINAL MAP) Proposed Improvements should be described in the submittal including:proposed recreation sites,trails(see SRP section 5.2 and Figures 3,4,5,6,7,8),stream crossings(see SRP section 5.3 and Figures 6,7,8),and trail amenities(see SRP sections 5.2.5,6.9,6.11,6.12),as well as 1 typical trail cross section and location for local trails(see SRP section 5.2.2 and Figures 3,4,5, 6,7,8,10,11),regional trails(see SRP section 5.2.1 and Figures 2,3,4,5,6,7,8,9), maintenance roads(see SRP section 5.2 and Figures 3,4,5,6,7,8,9,10)and maintenance access(see SRP section 5.2).The submittal should show proposed grading in the low flow channel and within the flood plain,engineering and bioengineering treatments,removal of rubble (see SRP sections 3.1.1,3.1.3,4.1,4.2,4.6,5.5,6.3,6.4,6.16),structure setbacks and wildlife setbacks(see SRP sections 4.6,5.1,6.1 and Figures 1,3,4,5),private development buffer(see SRP section 5.2.1 and Figures 3,4)adjacent to regional trail,and development interface(see SRP section 5.4 and Figures 6,7,8,12,13,14).Show both existing and proposed:creek center line,top of bank for low flow line,and top of bank and toe of bank for flood plain.(see SRP sections 3.1.1,3.1.3,4.1,4.2,4.6) Accompanying Data and Reports(FINAL MAP) $oils Report should show areas of existing and potential instability within the flood plain and should include soil test results for agriculture suitability for restoration plantings.(see SRP sections 3.3.6,4.4,4.5,6.17) Site Color Slides(TENTATIVE MAP) Color Slides should show representative creek conditions,including the low flow channel,flood plain terrace,vegetative cover,stream crossing,drop structures,existing bank treatments,rubble, and large areas of bare soil. • Special Information(FINAL MAP) Specimen Tree Protection should include provisions for tree protection including,accurate locations of trees to be removed and saved,species,diameter at breast height(DBH),contractor restrictions and equipment requirements.The submittal should also show proposed grading and structures near trees,including cutting of roots in the least damaging manner,preventing the storage of materials and equipment around protected trees,avoiding changes in drainage patterns around trees,cultural treatments,construction monitoring by a qualified arborist,and other protection measures.Mitigation of removed trees may be shown in the Creek Restoration Plans. (see SRP sections 6.5,6.14) A Biological Corridor Connections Map prepared by a qualified biologist is required,showing on a map at approximately 100-scale,the north-south corridor connections along Tassajara Creek and the east-west biological corridor connections from Tassajara Creek to open space lands via its tributaries.The width of the corridor at regular intervals and at constrictions should be specified,existing barriers to wildlife movement,proposed impediments(improvements and land uses)to wildlife passage and mitigation of impediments,such as:placement of culvert under road crossing,fencing to funnel wildlife or plantings.Any proposed fencing within the stream corridor or its tributaries that could restrict or impair free movement of wildlife,or that may be used to funnel'wildlife movement into safe passage and away from roads or other hazards should be shown,with a description of its type and location.(see SRP sections 6.1,6.2,6.10) 2 Creek Restoration Plans(mitigation and/or habitat restoration)at 50-scale or less should include: restoration goals,equipment requirements,proposed earthwork,proposed engineering and bioengineering structures,dewatering,drainage treatment,clearing,debris removal and disposal, exotics eradication,soil stockpiling,soil treatments,site preparation,planting,seeding, transplanting,irrigation,establishment maintenance,contractor access and staging areas, sensitive areas protection provisions,construction precautions and restrictions,site clean up, qualifications of contractors,construction supervision,contingency plans,scheduling and phasing.(exotics eradication,planting,seeding,irrigation,monitoring and landscaping plans are described below.General elements are referenced in SRP sections 6.4,6.8,6.14,6.16,6.17) Exotics Eradication Plans should include:target exotic species,location and protection of sensitive resources,manual,mechanical and chemical treatments,target plant size,number of applications, regrowth,exotic seed control,schedule and climatic constraints,safety precautions,and if chemicals are used,compliance with Federal,State and local water quality regulations,list of approved chemicals,application specifications,disposal of spent containers,requirement for Licensed Pesticide Applicator or Pest Control Advisor.(see SRP section 6.15) Planting and Seeding Plans for Tassajara Creek and its tributaries should include:planting of stock,densities,procurement procedures,provisions for species substitutions,seed pretreatment, soil pretreatment,storage and handling of plants and seed,planting and seeding methods, watering in plants,areas expected to revegetate naturally,and human and animal protection.(see SRP sections 6.2,6.18,6.20,6.21,6.22,6.24,6.25,6.26,6.27,6.28,6.29,6.30,6.31,6.32,6.33, 6.35) Include test results to support restoration plantings for:soils testing for agriculture suitability and groundwater depth information(either from testing or inferred by existing vegetation).(see SRP sections 6.17,6.19,6.23) Since Irrigation will in most cases be temporary,irrigation installation can be provided as a design-build,however applicant should show irrigation type,water pressure,and provisions for point of connection and removal of temporary system.(see SRP section 6.34) Establishment Maintenance and Monitoring Procedures should be provided,addressing warranty period,weeding procedures,erosion control,irrigation regime,maintenance of the irrigation system,procedures for cessation of irrigation,debris removal,replanting and reseeding,cultural requirements and treatments appropriate to native plantings,site protection,responsible party and contingency measures.(see SRP sections 6.36,6.37,6.38,6.39,7.2) Copies of Permits from California Department of Fish and Game and Army Corps of Engineers, permit conditions and performance standards should be provided.If habitat mitigation is included within the stream restoration corridor,this should be clearly represented to the City of Dublin.(see SRP sections 6.7,7.2) Landscaping Plans A s jacent to Tassajara Creek or its tributaries showing:structure setbacks, wildlife setbacks,private development buffer adjacent to regional trail,screening with vegetation and development interface should be shown.Planting zones,species,propagule type,size of 3 stock,provisions for species substitutions,soil pretreatment,planting and seeding methods, watering in plants,human and animal protection should be shown or described.Include test results to support landscape plantings for:soils testing for agriculture suitability.Establishment maintenance procedures addressing weeding procedures,erosion control,irrigation type, irrigation regime,debris removal,cultural requirements and site protection should be described. (see SRP sections 6.8,6.9,6.11.6.12,6.13,6.17,6.19,6.20,6.34) For help in understanding this information,please contact: PLANNING DEPARTMENT STAFF CITY OF DUBLIN 100 CIVIC PLAZA DUBLIN,CA 94568 (510)833-6610 • RESOLUTION NO. 96 - A RESOLUTION OF THE PLANNING COMMISSION OF THE CITY OF DUBLIN RECOMMENDING THAT THE CITY COUNCIL APPROVE THE EASTERN DUBLIN COMPREHENSIVE STREAM RESTORATION PROGRAM AND THE TASSAJARA CREEK LOWER REACH IMPLEMENTATION PLAN WHEREAS,the City of Dublin adopted the Eastern Dublin General Plan Amendment and Specific Plan on May 10, 1993 and the Dublin voters approved the Eastern Dublin General Plan Amendment and Specific Plan on November 2, 1993; and WHEREAS,the Final Environmental Impact Report(FEIR) for the Eastern Dublin General Plan Amendment and Specific Plan contains Mitigation Measure 3.7/12.0, and the Eastern Dublin Specific Plan contains Action Program 6F that requires the City to prepare and approve a comprehensive stream corridor restoration program for the Eastern Dublin General Plan Amendment area; and WHEREAS,the Eastern Dublin Comprehensive Stream Restoration Program(Stream Restoration Program) implements Mitigation Measure 3.7/12.0 of the FEIR and Action Program 6F of the Eastern Dublin Specific Plan, and is consistent with the policies and action programs of the Eastern Dublin General Plan Amendment and Chapter 6 - Resource Management of the Eastern Dublin Specific Plan to the extent that the guidelines and standards of the Stream Restoration Program will promote the restoration, enhancement and stabilization of Tassajara Creek and its tributaries; and WHEREAS,the Stream Restoration Program shall be applicable to the Eastern Dublin General Plan Amendment area and shall be enforced for all Eastern Dublin rezoning and tentative map/final map applications; and WHEREAS,the City of Dublin shall be the ultimate authority for determining and implementing appropriate guidelines for stream restoration; and WHEREAS,the Stream Restoration Program includes recommended guidelines and standards for stream restoration, and the City of Dublin may apply some flexibility when implementing these guidelines and standards and allow some guideline modifications and negotiations; and WHEREAS,trails, creek crossings and maintenance road extensions, as shown in the Stream Restoration Program, can be interrupted as a result of private property, topographical or other site constraints, as long as trail/maintenance road ingress and egress points are provided at these points of interruption; and WHEREAS,the Tassajara Creek Lower Reach Implementation Plan sets forth the framework for ownership, maintenance, and operation responsibilities for the portion of the Tassajara Creek between the 1-580 Freeway and Gleason Drive, and the City staff shall use this plan for implementing the Stream Restoration Program; and WHEREAS,the Stream Restoration Program has been reviewed in accordance with the provisions of the California Environmental Quality Act(CEQA) and the State CEQA Guidelines, and no new effects could occur and no new mitigation measures would be required for the project that were not addressed in the Final Environmental Impact Report (FEIR) for the Eastern Dublin General Plan Amendment and Specific Plan, and the project is within the scope of the FEIR. The project implements mitigation measures of the FEIR and an initial study will be conducted for each development application that is required to comply with the Stream Restoration Program document; and WHEREAS,the Planning Commission held a public meeting to consider this project on July 16, 1996; and WHEREAS, the Staff Report was submitted recommending that the Planning Commission recommend to the City Council approval of the Stream Restoration Program. NOW, THEREFORE, BE IT RESOLVED THAT THE Dublin Planning Commission does hereby recommend that the City Council approve the Stream Restoration Program and the Tassajara Creek Lower Reach Implementation Plan, as defined in Exhibits A and B, respectively, of the Planning Commission Staff Report dated July 16, 1996. PASSED,APPROVED AND ADOPTED this 16th day of July, 1996. AYES: NOES: ABSENT: Planning Commission Chairperson ATTEST: Community Development Director g:\eastdubl\stream\pereso\crc TASSAJARA CREEK LOWER REACH(1-580 TO GLEASON DRIVE)IMPLEMENTATION PLAN MAINTENANCE/OWNERSHIP/OPERATION RESPONSIBILITIES (Keyed to attached Figures 3a and 3b of the Draft Stream Restoration Program) ZONE 7 • Creek Corridor Ownership(includes creek channel;flood control channel/terraces on both sides of creek;30' minimum structure setback on both sides of creek;and maintenance roads between 1-580 and Dublin Blvd.on both sides of creek) • Creek Channel Operation;and Maintenance for Flood Control and Water Conservation Purposes Only,as per the March 18,1987 Agreement Between Zone 7 and the City of Dublin and any Subsequent Agreement Modifications EBRPD • Regional Trail/Maintenance Road and 30'Structure Setback on East Side of Creek-Maintenance and Operation(between Dublin Blvd.and Gleason Drive) CITY OF DUBLIN(i.e..landscape&lighting district) • Local Trail/Maintenance Road;30'Structure Setback;and Optional Trail Landscape Plantings Requiring Permanent Irrigation on West Side of Creek-Maintenance(between Dublin Blvd.and Gleason Dr.-see Fig.3b) • Optional Landscape Plantings Requiring Permanent Irrigation on East Side of Creek-Maintenance(between Dublin Blvd.and Gleason Dr.-Fig.3b) • Optional Landscape Plantings Requiring Permanent Irrigation on Both Sides of Creek-Maintenance(between 1-580 and Dublin Blvd.within the stream corridor) COUNTY OF ALAMEDA • Required Restoration Plantings-Establishment and Maintenance (County shall establish and maintain for approx.3 to 5 years) • Optional Landscape Plantings that do not Require Permanent Irrigation-Establishment and Maintenance (County shall establish and maintain for approx.5+years) • Optional Landscape Plantings Requiring Permanent Irrigation-Establishment only. AGREEMENTS NEEDED City/County Agreement with Zone 7: Creek Corridor Dedication Creek Corridor Operation and Maintenance For Flood Control and Water Conservation Purposes Only Fencing Prohibiting Vehicular Access Acknowledgment of City's Landscape and Lighting District City/Zone 7/County Agreement with EBRPD: Regional Trail/Maintenance Road and 30'Structure Setback on East Side of Creek(between Dublin Blvd.and Gleason Drive) g:leastdubl\streamMainten1 EXHIBIT C TASSAJARA CREEK LOWER REACH IMPLEMENTATION PLAN Optional landscape plantings Required quir Optional landscape plantings restoration plantings?. P gs ,� Landscape Structure �� easement setback 1 Flood control channel //' 1 Structure Landscape f I / Flood control channel setback easement (20' min) (30' min (Q100) (0100) /(30' min) 1(20' min)/ CI) (311 O Existing0 top of bank -1 Existin Excavate for flood g grade control channel ,--,--->,\;,77-47— - / 1/ / /.1 , -I -- ( '''<\‘' / V—v— — --— -7,17Y ,i i-1-0--- Maintenance road �j-////771 tYP' Maintenance road ' / g,1 (Meandering low flow channel Wildlife setback• / / Wildlife_ sefback• (100' min.) I I (f00 / min.) ,( _ Stream Corridor width varies Measured from e,�istiny fop of bark TYPICAL CROSS SECTION LOWER REACH SUBREACH I - 1580 TO DUBLIN NTS Tassajara Creek Fig. 3a Ownership Flood Control Maintenance Establishment Maintenance Establishment Ultimate Maintenance & Operation of Required of Required of Optional Maintenance Restoration Restoration/ Landscape of Optional Plantings Optional Plantings Landscape Landscape Plantings Plantings (± A 3 - 5 years) Zone 7 Zone 7 Zone 7 N/A N/A _ County City - LLD B Zone 7 Zone 7 Zone 7 County County County N/A C Zone 7 Zone 7 Zone 7 County County N/A N/A D Zone 7 Zone 7 Zone 7 County County County N/A E Zone 7 Zone 7 Zone 7 N/A N/A County City - LLD TASSAJARA CREEK LOWER REACH IMPLEMENTATION PLAN _, Optional landscape plantings .1/ Required , Optional landscape plantings restoration plantings Sfructure Structure setback setback (30' min) 1 Flood plain terrace / • / Flood plain terrace �(30' min) Trail/roa Trail/roa right-of-wa © A right-of-way J Excavate for Top of bank 0 flood plain terrace as required Excavate for flood plain 15 year le vel2 C terrace as required Existing grade — ii _iiil= Regional frail/ maintenance road Local trail/ see fig. 9 maintenance road see fig. 10 Existing grade Wildlife setback* Wildlife setback• -. (100' min.) 1 1 (100' min.) Stream Corridor width varies •Measured from existing top of bank TYPICAL CROSS SECTION LOWER REACH SUBREACH 2 - DUBLIN TO GLEASON NTS Tassajara Creek Fig. 3b Ownership Flood Control Maintenance Establishment Maintenance Establishment Ultimate Maintenance & Operation of Required of Required of Optional Maintenance Restoration Restoration/ Landscape of Optional Plantings Optional Plantings Landscape Landscape Plantings Plantings (± 3 - 5 years) A Zone 7 Zone 7 City - LLD N/A N/A County City - LLD B Zone 7 Zone 7 Zone 7 County County County N/A C Zone 7 Zone 7 Zone 7 County County N/A N/A D Zone 7 Zone 7 Zone 7 County County County N/A E Zone 7 Zone 7 EBRPD N/A N/A EBRPD EBRPD Related Eastern Dublin Specific Plan Action Program 6F and EIR Mitigation Measure 3.7/12 MM 3.7/12.0 (Program 6F). The City should work with Zone 7 and the Department of Fish and Game to develop a comprehensive stream corridor restoration program that identifies a detailed set of criteria for grading,stabilization and revegetation of planning area stream channels. This program shall be developed soon after approval of the General Plan Amendment and Specific Plan. The program would provide guidelines for plant species, planting densities,and long-term maintenance requirements and responsibilities. Such a program will facilitate development approvals and insure a consistent standard for stream channel improvement throughout the planning area. The program should identify the procedures to be followed by applicants for development,permits to be obtained,and improvement and revegetation practices to be implemented. Program 6F: The City should work with Zone 7 and the Department of Fish and Game to develop a comprehensive stream corridor-restoration program that identifies a detailed set of criteria for grading,stabilization and revegetation of planning area stream channels. The program would provide guidelines for plant species,planting densities,and long-term maintenance requirements and responsibilities. Such a program will facilitate development approvals and insure a consistent standard for stream channel improvement throughout the planning area. The program • should-identify the procedures to be followed by applicants for development,permits to be obtained,and improvement and revegetation practices to be implemented. The program should be reviewed by East Bay Regional Parks District. g:\eastdubl\stream\attch I Attachment 1 w it • Eastern Dublin Comprehensive Stream Restoration Program SUMMARY Major Regional Resource The watercourses found throughout the Eastern Dublin area are linked into a comprehensive linear corridor system. This system includes one major creek,Tassajara Creek, its tributaries,and a number of intermittent streams that drain in a southwesterly direction. The Specific Plan designates these water courses as linear open space corridors that link community activity centers,residential areas,and open space. These stream corridors are planned to have pedestrian and bicycle trails that will accommodate the movement of pedestrians,bicyclists,and equestrians throughout the planning area with minimal conflict from vehicular traffic. Where feasible,these trails will connect into adjoining regional trails systems(i.e.East Bay Regional Park District's and Livermore Area Recreation and Park District's trail systems.) Tassajara Creek functions as a major regional resource for wildlife and water flow movement.Tassajara Creek provides uninterrupted connections to other significant open space areas in eastern Dublin(i.e.Camp Parks)and Contra Costa County(i.e.Hidden Valley,Mt. Diablo,Morgan Territory,Black Diamond Mines and Contra Loma Regional Parks.) Tassajara Creek also serves as a means for transporting stream runoff and groundwater seepage through and away from the planning area. Tassajara Creek must be able to contain and transport (convey)flood flows up to and including the 100-year design flood. Channel Stability and Erosivity.Setbacks The consultants discovered that Tassajara Creek is very unstable. Preliminary analysis shows that it is a channel in transition with reaches shifting their channel patterns and habit. Detailed professional hydrologic and possibly geotechnical studies based on the Stream Restoration Program need to be completed prior to establishing development setbacks or altering the channel form. These studies will confirm existing conditions and will identify requirements to grade the flood plain terrace to accommodate flood flows. Channel and bank stability improvements should be designed to reduce or eliminate the potential channel transitions. The City's minimum setback along open watercourses,which may be increased at the discretion of the Public Works Director,is described in Ordinance 52-87. Figure 1 of the Stream Restoration Program shows a hypothetical example of channel setbacks necessary to account for the future channel transitions,which complies with the City's ordinance. Water Quality of Runoff and Groundwater All future Eastern Dublin development projects must comply with the City's erosion control and water quality regulations. The quality of groundwater and urban runoff into Tassajara Creek and its tributaries should meet the Best Management Practices,or BMPs and other practices as identified in Section 9.3.2 of the Eastern Dublin Specific Plan. BMPs are Attachment A- measures that would prevent polluted water runoff from developed areas from entering the natural waterway systems. The draft Grazing Management Plan includes guidelines that would reduce water quality impacts associated with cattle grazing,i.e.cattle should be grazed and watered at alternate sources outside the stream channel. The Stream Restoration Program concludes that enhancement,restoration and landscaping between future developments and the creek should stabilize surface sediments. Reclaimed Water Reclaimed water can be used for landscape irrigation or establishing riparian vegetation within the creek study area.The Stream Restoration Program recommends that the use of reclaimed water to irrigate restoration plantings or trail landscaping should not impair water quality standards. Zone 7 is currently conducting a major regional reclaimed water study. This study will assess the potential impacts of wastewater application on ground and water surfaces. In the interim,Zone 7 recommends that irrigation systems should be designed to be easily switched to reclaimed water systems when such systems become an accepted policy. Flood Control If existing conveyance(the ability to carry flood flows)is inadequate,flood control alternatives,such as broadening,deepening,and smoothing the channel,and constructing levees and bypasses should be considered. Channel Modifications a:id Stabilization/Bioengineering Techniques Channel modifications or improvements should accommodate projected flood flows and extensive revegetation that avoids the need for periodic vegetation removal. The Stream Restoration Program states that the flood plain terrace should be managed to support non- irrigated grasses and where channel modifications are required,the channel should be shaped and graded to contours with a natural appearance. A flood plain terrace is necessary to accommodate additional flood flows. The Stream Restoration Program emphasizes that preserving the creek is paramount to preserving the existing vegetation and wildlife corridor,consistent with the Specific Plan's restoration goals. Most importantly,the channel should be allowed to naturally revegetate,erode and meander within the flood plain terrace. The document recommends that non-structural,or bioengineering solutions should be used to increase channel capacity and stabilize stream banks while providing habitat value,and provides examples of such solutions,e.g.vegetation or boulders. Bioengineering is a low-tech method of construction using living plants in combination with non-living,or inorganic materials (i.e.hard structures.) • Resource Protection.Restoration and Mitigation Erosion and hydrologic considerations may allow for flexibility in the biological setbacks for Tassajara Creek and its tributaries. As long as the hydrological setback is met,the biological or wildlife setback may be arranged to incorporate more valuable habitat on one side of the tributary at the expense of less valuable habitat on the other side. Under no circumstances should the wildlife setback be less than 50 feet on one side. The Stream Restoration Program's revegetation guidelines shall apply where creek channel grading modifications create large bare soil areas or remove large stands of vegetation. Where major grading and modifications are proposed to accommodate flood control and access along Tassajara Creek between Gleason Road and I-580 Freeway,restoration plantings shall be required to provide stabilization and wildlife habitat,subject to the California Department of Fish and Game review and approval. In reaches of Tassajara Creek where existing and native vegetation is abundant and diverse,needing no modification,little to no planting is anticipated. However,in this situation, the City will require some native vegetation enhancement,consistent with the Specific Plan Policy 6-11 that requires all stream corridors to be revegetated with native plant species to enhance their natural appearance and improve habitat values. Chapter 6 of the Stream Restoration Program includes resource protection,restoration and mitigation guidelines for plants and wildlife. This is a very comprehensive chapter outlining methods and guidelines for plant and wildlife habitat enhancement and restoration that project applicants can utilize while preparing a creek restoration plan. Study Area-3 Reaches For planning and implementation purposes,the Tassajara Creek study area was divided into 3 reaches: lower reach(I-580 Fwy.to Gleason Rd.);middle reach(Gleason Rd.up to and including the EBRPD staging area);and upper reach(EBRPD staging area to the Contra Costa County line.) Figure 2 of the Stream Restoration Program depicts these reaches. Channel Cross Sections Conceptual Cross Section for Lower Reach-Subreach 1(Fig.3a of Stream Restoration Program): 1)creek channel(below Q15)-meandering low flow channel;trapezoidal channel 2)restoration plantings below Q15 3)flood plain terrace(existing or graded terrace outside the creek,within Q100) 4)structure setback from existing top of bank-(above Q100) 5)optional landscape plantings within and outside the Q100 that will be maintained by the City of Dublin 3 Conceptual Cross Section for Lower Reach-,Subreach 2(Fig.3b of the Stream Restoration Program): 1)existing creek channel(below Q15) 2)restoration plantings below the Q15 3)flood plain terrace(within Q100) 4)structure setback from existing top of bank(above Q100) 5)optional landscape plantings within and outside the Q100 Conceptual Cross Section for Middle Reach(Fig.4 of the Stream Restoration Program): 1)existing creek channel(some sections contain Q100,other sections do not)-supports vegetation 2)flood plain terrace(area above existing creek channel,or the area graded to accommodate the flood flows below the Q100) 3)structure setback(above the Q100) Conceptual Cross Section for Upper Reach(Fig.5 of the Stream Restoration Program): 1)existing creek channel(readily contains 100 year flood flows)-supports riparian vegetation at lower elevations 2)hydrological-wildlife structural setback outside the existing creek channel Stream Setbacks • Creek and tributary setbacks are as follows: 1)structure setback must be above the 100 year flood flows,or Q100(this is at an elevation where the worst rain will flood the area 1 time within 100 years);2)Tassajara Creek and major creek tributary-100 foot minimum wildlife setback from top of existing bank channel;and 3)minor creek tributary-50 foot minimum wildlife setback(trails sited within the setback should be sited furthest away from the creek.). The combined width of the flood plain terrace and the structure setback should be a minimum of 100 feet along both sides of the incised or graded channel to comply with the California Department of Fish and Game requirements,unless an exception is negotiated with the Department biologists. For the lower and middle reaches,there should be a 30 foot minimum structure setback (or setback from development)from outside the flood plain terrace. Wider setback should be encouraged. Trail and maintenance access right-of-way should be located within this 30 foot setback area to maximize public safety,enhance access for police patrols,minimize wildlife disturbance and minimize trail maintenance resulting from erosion or siltation. The Stream Restoration Program encourages the landscaping and vegetation of adjacent development for creating soft edges and erihancing/enlarging the trail open space and maintenance corridor,and eliminating sidewalks in savor of the pedestrian and bicycle use of the regional trail. 4 • The wildlife and hydrological setbacks for the upper reach overlap. The greater of the two controls the final outside edge of the stream corridor. The hydrological setbacks incorporates structural and slope bank failure considerations for the character of this channel portion. The wildlife setback is still 100 feet from the top of the existing bank channel. The recommended minimum setbacks may be altered where prevailing conditions warrant a different approach. A key circumstance would be the upper reach where the channel is 50 feet deep and the banks are nearly vertical. The Stream Restoration Program recommends a setback of 120 feet from the top of bank to accommodate the transitional,unstable nature of the channel. The Stream Restoration Program states that due to the serious liability related to potentially inadequate setbacks along Tassajara Creek,the City should retain their own hydrology consultant to evaluate any hydrologic studies. Trails and Maintenance The Stream Restoration Program includes a trail and maintenance roadway system that provides multi-purpose open space corridors capable of accommodating both wildlife movement, pedestrian,bicyclist and equestrian circulation,consistent with the Specific Plan policies. The open space stream corridors integrate natural open space areas,developed parks and recreation areas. The trail and open space network links regional and local trails,employment centers, residential areas,schools,neighborhood parks,and open space. The trail and maintenance roads should be combined to provide safe pedestrian and 2- way bicycle use and adequate maintenance areas. In the upper reaches where the banks are steep, creek access should be discouraged for safety reasons. The trail should be located outside the established setback,the fencing strategically placed,and proper signage installed. Zone 7 will require maintenance access,or gravel roads on both sides of the creek where there is no regional or local trail. Zone 7 requires 15 foot wide all-weather surface roads with a 6 inch compacted aggregate base,both preferably located above the Q 100. If this is not practical, Zone 7 may accept one lower maintenance road above the Q15,paved in asphalt concrete,or concrete. Figures 6 through.8 show a conceptual plan view of the trail and maintenance roads. Figures 9 through 11 show trail standards for the regional trail,local trail and the maintenance roads. Creek Tributaries-Trails The creek tributaries should be improved with local trails designed to connect to the regional trail and provide convenient pedestrian and bicycle connections between neighborhoods and other destinations within the plan area. Also,the Stream Restoration Program states that local trails should utilize the tributary as an open space corridor connection. 5 Regional Trail/Maintenance Road The regional trail/maintenance road shall be provided along one side of the creek, consistent with EBRPD and Zone 7 requirements. The regional trail shall be designed in compliance with the City'•s Parks and Recreation Master Plan. The combined regional trail and maintenance road shall include a 12 foot wide paved pathway and rocked shoulders(4'wide on one side,and 2'wide on the other.) This regional trail should accommodate pedestrians, bicyclists and equestrians. This trail will also adequately serve Zone 7's all-weather surface requirement for maintenance access. Local Trail/Maintenance Road Although the Specific Plan requires only one north-south trail along Tassajara Creek,the Stream Restoration Program also provides guidelines and standards for a local trail system and a combined local trail and maintenance road system. This local trail/maintenance road system would provide connections between residential neighborhoods and destinations,such as the regional trail,schools,parks,employment centers,open space,etc. The document also includes standards for trail/park staging areas and trail heads for hiking and equestrian trails,stream crossings and the development-corridor interface. Access to both regional and local trails should be controlled through use of bollards, gates,fences or similar systems acceptable to the emergency response agencies. These methods of controlling access would prohibit undesired vehicle access,while allowing for maintenance and emergency vehicle a:cess and encouraging bicycle use of the local trails. Development-Corridor Interface Development abutting the stream corridor should meet certain criteria,such as preserving and enhancing the creek's biological values,convenient corridor access,enhancement of the visibility and character of the stream corridor,etc. Figure 12 of the Stream Restoration Program shows three types of road systems that should be incorporated into the project design for providing an appropriate development-stream corridor interface: single loaded streets,loop streets and cul-de-sacs. Development that backs directly into the stream corridor should be avoided. In addition, residential development should be oriented towards the creek as a visual amenity and schools and parks should be designed to take advantage of creekside settings and educational opportunities. Figure 13 depicts recommended commercial development setbacks along creeks that would promote a smoother transition to the open space area. Screening of parking lots,storage areas,loading docks,trash receptacles,etc.should be accomplished through landscaping. Figure 14 depicts recommended pedestrian trail access development configurations. 6 • Implementation and Management In compliance with the Specific Plan,prior to any final map approvals for projects adjacent to the Tassajara Creek or its tributaries,the City shall establish a mechanism(e.g. landscape and lighting district)for the ownership,management and long-term maintenance of the stream open space corridor. These improvements would include stream corridor restoration, flood control improvements and trail construction. The City should establish this mechanism to cover the long-term costs of maintaining public facilities(i.e.,trails,roads,benches,vegetation management,etc.)along the stream corridors. The other ownership and maintenance funding sources include: home owners association,other public agencies(i.e.,EBRPD,Zone 7,etc.), special assessment districts,bond and tax measures,etc. It is expected that these corridor improvements will take place in a number of phases based on ownership patterns and timing of application submittals. The preferred phasing would be improving the entire lower reach first,middle reach second,and upper reach third. Funding Mechanisms Zone 7 and EBRPD may have some funding earmarked for flood control and trail improvements. The City's Parks and Recreation Master Plan describes other funding sources for open space acquisition,capital improvements and operations. Long-term maintenance and management should be accomplished through the development of cooperative agreements between the City,Zone 7 and the EBRPD that would set common management goals and activities and joint financing provisions. The maintenance agencies should develop and enforce long-term maintenance and management guidelines and standards that promote the Specific Plan stream restoration and preservation policies and the Stream Restoration Program guidelines and development standards. g:\eastdubl\streams\stan'rpt • 16034-0 mAcKaY&somPs � R CIVILENGINtERING LAND PLANNING LAND SURVEYING July 15,1996 Carol Cirelli,Senior Planner City of Dublin 100 Civic Plaza Dublin,CA 94568 Subject: Eastern Dublin Comprehensive Stream Restoration Program Dear Carol: On behalf of our client,Jennifer Lin,we have reviewed the final draft of the City's proposed Stream Restoration Program prepared in cooperation with Sycamore Associates. We met with Marylee Guinon of Sycamore Associates and you on July 5, 1996,to discuss comments and questions expressed in our previous response letter of April 23, 1996(copy attached). A number of concerns were resolved in our meeting,however,there are still many specific requirements and guidelines contained in the current document that we see as problematic and generally unworkable,particularly with respect to implementation of a land plan for Dublin Ranch in accordance with the Eastern Dublin Specific Plan. Our primary concerns with the proposed program still revolve around references to a 100' minimum CDF&G"standard"for creek setbacks as a legal requirement;procedures by which creek set backs are measured;lack of flexibility for implementing the guidelines and allowance for guideline modifications;and cost/phasing/financing/jurisdictional maintenance issues that are not clearly addressed in the document. One of our most notable concerns involves the document's repeated reference to the 100 foot setback as a CDF&G"standard". At numerous locations in the text and exhibits it seems to be implied that the 100 foot setback is a legal requirement,however,this setback is only a recommendation that CDF&G can make during the environmental review and permitting processes. The document should be reworded to state that CDF&G"typically recommends a 100 foot setback...". The need to revise this inaccurate wording is further substantiated by the text wording within the Eastern Dublin Specific Plan under Program 6G. The recommendation on page 59 that setbacks from major tributaries"should never be less than 100 feet"or a"minimum of 100"'is too rigid and precludes the opportunity for negotiating a lesser setback with the regulating agency. In addition,this language does not account for site specific conditions where a flat 100'setback is not warranted such as areas that are degraded, have little or no vegetation,have artificial materials or surfaces(rip rap,gunite,etc.)on the bed or banks,etc. Flexibility and allowances should be made equally for actual physical conditions in both Tassajara Creek and its tributary channels. Site conditions which would warrant such flexibility in offsetting or reducing the recommended setbacks include creek or tributary sections DAVE-Coma:1996:1603DRIVIE,SUITE Borah 5142 FRANKLIN DRIVE,SUITE B PLEASANTON,CALIFORNIA 9458&3355 PHONE(510)225-0690 FAX(510)225-0698 OFFICES: FAIRFIELD PLEASANTON ROSEVILLE SACRAMENTO SAN JOSE Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 2 with lower quality of habitat,adjacent developed land uses,stable embankment conditions, minimal existing or expected areas of disturbance,minimal vegetative cover,etc. On page 59, it is also noted that erosion and hydrologic considerations "may allow" for flexibility in determining the biological setbacks for tributaries in terms of both distance and offsetting on the different sides. The wording of this sentence should be amended to read: "should allow": Additionally,this greater level of flexibility should also be applied to setbacks along Tassajara Creek as well as its tributaries. A second area of concern is the procedure by which setbacks are measured. Based on the description on page 26 and in Figure 1,the recommendation that setbacks be measured from the outermost limit of a stream meander is excessive in terms of the substantial land area designated for future development in the Eastern Dublin Specific Plan which would be pre-empted. In addition,the data in this Program does not conclusively document that these meanders are particularly dynamic and is not consistent with the field observations of our consultant team. In light of the fact that the upper reach of the channel is deeply incised and contains what presently appears to be stable vegetative cover as well as the minimal level of field investigation and analysis which was permitted for this study effort, it is questionable whether the setback distances recommended are appropriate. Due to of the loss of developable land associated with this setback approach, it would be worthwhile to consider providing stabilization measures for such creek sections which might potentially allow for land areas between meanders to be used if an adequate setback from the top of bank is provided. It is suggested that aerial photos taken over the last 40-50 years of Tassajara Creek and its tributaries be thoroughly analyzed to accurately determine whether these meanders have been actively changing over this time frame. A more detailed and site specific analysis might also be considered to further identify where future creek meanders might occur in order to determine if a flat setback distance of 100'or greater is really justified. Another area of concern is the document's apparent lack of flexibility with respect to implementing and modifying the proposed guidelines. The City's staff report suggests that the City "may apply some flexibility implementing these guidelines and allow some guideline modifications,only if these changes meet the overall intent of the Specific Plan goal,policies and action programs,and Stream Restoration Program criteria and guidelines." Much of the language in the Program,however,has the effect of placing other goals in the Eastern Dublin Specific Plan in a subservient position to the"guidelines"of other agencies. We think this approach is backwards. The changes suggested in this letter re-enforce the flexibility described in the staff report without sacrificing either the overall intent of the Program or the primacy of the City's role in guiding development in Eastern Dublin. Thus,we believe that the document should clearly state(probably in the implementation section)that the City of Dublin is the ultimate authority in determining the appropriate application of these guidelines. Other problematic issues involve the cost,phasing,monitoring,ownership,maintenance and financing of the Program. Project construction is suggested to not begin until all required permits have been secured and,in the event that construction is phased,permits should be secured for the entire project before construction begins in any one area. We completely disagree DAVECor es.:1996:16039-0cg7/11/96StreamRestoratn Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 3 with both of these requirements. Normal practice is for some construction activities to typically begin before all permits are secured. Additionally,the proposed requirement to secure all permits for the entire project before construction commences is inconceivable as many years could occur between various development phases of a large project such as Dublin Ranch. This would be especially problematic for permits(e.g.Corps of Engineers Section 404 permits) which stipulate that construction must be initiated within a set period of time following issuance of the permit. There is very little detail provided in the text with respect to costs for establishment and maintenance of revegetated stream corridor areas. In order for affected land owners to be able to clearly understand the financial impact,a section needs to be added which addresses specific cost items,unit prices,assumptions,etc.applicable to this Program. On page 14 the document specifies that the City of Dublin is interested in having EBRPD and Zone 7 assume ownership of and manage portions of the stream corridor. However,the text also needs to identify specifically where local trails and trail easements are to occur through proposed development areas and along tributaries,as well as who will own,manage,fund and assume liability for them. We are also interested in understanding what the ramifications to Dublin Ranch would be if the stream corridor lands within their property area dedicated to EBRPD. What would be the impact with respect to future maintenance,monitoring,and liability for such lands? Since we are not fully aware of the consequences of dedicating these stream corridor lands to EBRPD,we reserve the right to discuss this issue in greater detail in the future. The project scheduling and phasing discussion on page 17 implies that activities along the Tassajara Creek corridor and its tributaries will be phased over time. However,no further detail is provided as to how various items will work together,what items need to be addressed as related to the entire reach of the creek,how costs of improvements would be paid for and shared in a benefit analysis,etc. Furthermore,on page 72,it is noted that restoration projects are to be phased when the project is too large or costly to execute at one time or when land ownership patterns and project administration necessitate the need for phasing. Phasing is expected to coincide with construction of the flood terrace,trails,and roads in conjunction with adjacent development. The text specifies that phasing would allow the City and landowners to establish procedures for"planning,plan review,permitting,construction,maintenance and monitoring". Exactly how these tasks will be coordinated and whether all landowners must buy into the procedures needs to be clearly addressed in the Program. Page 123 mentions that creek improvements will occur by reaches. It should be noted that the preferred phasing approach to move sequentially upstream with improvements may not coincide with timing of actual development priorities and infrastructure improvements. If these improvements are to occur by reach,at what point in the development process would they be constructed? How funding and reimbursement for improvements would be addressed also needs to be clarified as part of this discussion. A Habitat Monitoring Program and a Horticulture Monitoring Program are recommended to be established on pages 116-120. Please clarify how implementation of these programs will be DAVEC«res.:1996:16034ag7n1/%sveamneseonm Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 4 determined and funded. In addition,consideration should be given to merging these two programs since they're not significantly different. Whether the programs will be implemented by individual landowners or on a creek-wide basis also needs to be addressed. Additionally,we have some concerns about specific goals, standards and review times for the habitat and horticulture monitoring programs especially since the Corps will need to approve any such program if it is intended to meet mitigation requirements. If goals and standards are included with this programs,they should be written generally,not quantitatively,to provide consistency between the two programs. Additionally,any large area of planting,not just 100 or more trees as is specified in the text,should qualify as a representative sample plot. Furthermore,both of these monitoring programs should end if and when all the goals and standards have been achieved. In this regard,all references in the text to the establishment maintenance period and monitoring of mitigation areas under either program should state that they will apply for a period of up to five years or until program requirements have been achieved. Page 69 of the document specifies that an individual should monitor the establishment of the mitigation plantings for five years. Please clarify how will this position be filled,which agency will be responsible for implementing this action,and how this would be funded. On page 117 it is also recommended that a maintenance manual be developed prior to installation of plant materials. Since the purpose of the manual is to provide consistency for all phases,will this document be prepared for all phases at the commencement of the first development project? Also,who will prepare and oversee preparation of the document and how will funding and reimbursement work? Please provide clarification for these and any other related issues. Additional Items of Concern: In addition to our primary concerns described above, we would also note the following additional specific comments and questions concerning other elements of the proposed Comprehensive Stream Restoration Program: • With respect to plan review,the text should be revised to state that individual project development plans may be reviewed by EBRPD,Zone 7 and CDF&G but that those entities shall have approval authority only if they will become the ultimate owner/manager of the corridor within an individual land holding or,as in the case of CDF&G,an existing natural feature occurs which is protected by their agency (e.g. with respect to stream alteration). • It is recommended that the California Department of Fish and Game review and approve this document in writing prior to City adoption in order to gain their clear acceptance of the policies and procedures recommended within. This would help to reduce potential complications later in the permitting,construction monitoring and maintenance phases as future projects are proposed for development. In particular,we are concerned that the basic trail design proposed on both sides of the creek may not be in conformance with CDF&G desires. DAVECorrev.:1996:16039-0cg7/11/96StreamRestocam Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 5 • A map needs to be included in the document identifying all major and minor tributaries of Tassajara Creek referenced in the text. It is very confusing as to what constitutes a major/minor tributary and where each type of tributary is specifically located within Eastern Dublin. • With regards to the various detailed trail recommendations included,this document is not the appropriate vehicle to determine where local trails should occur in Eastern Dublin. Trail locations have been identified in the Specific Plan as well as the City's Parks and Recreation Master Plan and in some cases the recommendations in this document are not consistent with them. In the instance of Figure 11-Local Trail,the condition shown does not appear to exist within any of the stream or tributary corridor areas,but rather, through potential development areas. • Trail access points and staging area amenities as specified on pages 49-51 are excessive, both in quantity and type. • The various exhibits and the text should be revised to show local and regional trails maintenance roads restricted to only one side of a corridor. This action would help to further preserve and protect the habitat of the creek and tributaries.The Program's recommendations are clearly in conflict with Specific Plan Policy 6-13 which identifies the"single-side" approach for trails as a desired objective and needs to be revised accordingly. In addition, given the fact that there will be many fewer residents in proposed development areas surrounding the upper reach of Tassajara Creek than in more intensely developed areas to the south,there is no reasonable justification for providing both a regional trail and local trail within that particular area. The Specific Plan policies also do not specifically mandate that a dual trail system be provided along the creek corridor. • Figure 10 illustrates only one setback from the trail,that being on the creek side. However, in instances where no private buffer occurs,a minimum setback should be shown on the side which would abut development. • On page 49,it is suggested that the structure setback be widened to allow for the regional trail to meander. The justification as why additional meandering of trails beyond this setback limit needs to be clearly documented in the text. Rather than widening the structure setback, we suggest that the trail should be permitted to meander throughout the 100'wildlife setback in all reaches of the creek within reasonable safety limits. • The regional trail/maintenance road should be included within the wildlife setback area such as the local trail is shown on Figure 5. Also on Figure 5,as is typical of much of the upper reach,the top of bank should really start at the corner of the lower bench and not at the upper bench. • On page 50 under Section 5.2.4,it is stated that the regional trail/maintenance road should cross the creek at the staging area. Given the density of vegetation in that area,it would be worthwhile to explore alternative locations upstream or downstream for constructing the crossing. The existing crossing at the staging area is fine for pedestrians but would have to DA V E:Corres..1996:16034-0cg7/11/96StrearnRestora to Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 6 be reconstructed to accommodate vehicles and the impacts would be significant,particularly in terms of tree removal. The specific site for such future crossings should not be locked in as part of this Program. • The text on pages 68-69 specifies that no mitigation credits should be applied to street or landscape trees planted within the stream corridor as part of restoration efforts. In particular, trees planted within the stream corridor buffer,if present,should receive mitigation credits or park/open space credit. This text for this section should also require that tree plantings be the same species as those removed or compatible with those tree species planted within the adjacent stream corridor areas. • The recommendation under Section 3.3.5 on page 16 that all riparian trees be replaced at a 3:1 ratio regardless of DBH is excessive,particularly in the case of thickets of numerous small-stemmed trees such as willows. In some cases,a 3:1 replacement for a small but dense thicket could result in an inordinately high mitigation requirement. We recommend that in the case of dense, small-stemmed thickets of riparian trees that the acreage of vegetation impact be replaced on a 3:1 basis. Given the typically rapid growth of these species,this mitigation approach will result in full compensation for the habitat loss within a relatively short period of time. The last sentence in the paragraph should specifically exclude, by species name,invasive non-native trees such as tree-of-heaven,black locust,eucalyptus, etc. These invasive non-native trees should be excluded from the 3:1 replacement requirement. • Under the Specimen Tree Protection item on page 5,the text mentions that any existing native vegetation should be protected. This conflicts with page 68 of the text and page 2 of the checklist of Special Submittal Requirements for tentative subdivision maps which only protect trees. Additionally,the policy associated with this paragraph specifies that tree disturbance or removal should be"minimized." This sentence should be rewritten to apply only to native trees considered healthy as described in other sections of the Stream Corridor Restoration Program. • The basis for the recommendation that creek crossings should be located approximately every 2000 feet as noted on page 49 needs to be stated. Rather than dictating a certain distance between crossings,attempts should be made to locate creek crossings where widths between creek banks are reasonable,existing native vegetation is limited,sensitive habitat is not impacted,and embankment conditions are relatively stable. Additionally,if crossings are to be placed above future potential creek meander sections anticipated to be moving down the creek,as noted on page 51,the engineering and construction costs of such a crossing would likely be prohibitive. • Page 61 notes that soil compaction during the installation of bioengineering structures is discouraged,however,normal construction practices to prepare a site prior to improvements requires soil compaction to occur. Bioengineering structures and installation techniques should be discussed in greater detail in the text. • The requirement for soils testing,particularly with respect to agriculture suitability,seems extreme and costly for a project of this type. DA V E:Corres.:1996:16034-0cg9/11/%SheamRestora N • Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 7 • The text on page 115 specifies that ground or well water should not be used as a source for temporary irrigation uses,however,no documentation is provided as to whether ground water quality problems actually exist. This source is already used by existing vegetation which has access to the groundwater table. Additionally,the document on page 118 suggests that the irrigation system be monitored and repaired monthly which seems really excessive. • The document is not clear as to whether the HEC-II modeling for Tassajara Creek and its tributaries will be prepared by the City or Zone 7. This will affect when property owners undertake their own site specific HEC-II analysis. • We question whether a biological corridor connections map is actually necessary as identified on page 2 of the checklist of Special Submittal Requirements for Tentative Map. This map is basically a duplication of information already shown on various Specific Plan maps. In addition,the requirement to provide landscaping plans adjacent to Tassajara Creek or its tributaries as described on page 3 of checklist of Special Submittal Requirements for Tentative Map is also questionable. Most of the information to be illustrated on this map is already shown on other required maps. We believe that further clarification and reconsideration of various items in this document are warranted before it is considered for approval by the Planning Commission and Council. In particular,we would note again the need to revise those sections that are inconsistent with the Eastern Dublin Specific Plan and EIR. We would appreciate an opportunity to meet with you and other City staff further to discuss these items in greater detail before action is taken on the proposed Plan. Thank you for the opportunity to comment on the City's proposed Eastern Dublin Comprehensive Stream Restoration Program and for your consideration for our comments and questions. Sincerely, MACKAY&SOMPS w. Q � David W.Chadbourne cc: Eddie Peabody,Community Development Director T.Fairfield J.Tong M.Inderbitzen R.Andrade R.Harris D.Stephens,H.T.Harvey&Associates L.Berry,NUVIS DA V ECorres.:1996:160.#-0cg7/11/%StreamRestora N • 16034-0 MACKAY&somps CIVIL ENGINEERING LAND PLANNING LAND SURVEYING April 23,1996 Carol Cirelli,Senior Planner City of Dublin 100 Civic Plaza Dublin,CA 94568 Subject: Eastern Dublin Stream Corridor Restoration Program Dear Carol: Thank you for the opportunity to review and comment on the City's proposed Eastern Dublin Comprehensive Stream Restoration Program. Overall we commend this effort and support the program's goals,however,we believe the following comments noted by members of our Dublin Ranch consultant team will improve the document. Our primary concerns with the proposed program revolve around references to a 100'minimum CDF&G"standard"for creek setbacks as a legal requirement;procedures by which creek set backs are measured;justification for an additional 30'private development buffer required adjacent to creek corridor by EBRPD;and cost/phasing/financing/jurisdictional maintenance issues that are not clearly addressed in the document. One of our most notable concerns involves the document's repeated reference to the 100 foot setback as a CDF&G"standard". Numerous locations in the text and exhibits seem to imply that the 100 foot setback is a legal requirement,however,this setback is only a recommendation that CDF & G can make during the environmental review and permitting processes. The document should be reworded to state that CDF & G "typically recommends a 100 foot setback...". This revised wording is further substantiated by text within the Eastern Dublin Specific Plan under Program 6G. The recommendation on page 57 that setbacks from major tributaries"should never be less than 100 feet"or a"minimum of 100"'is too rigid. This language does not account for site specific conditions where a flat 100'setback is not warranted such as areas that are degraded,have little or no vegetation,have artificial materials or surfaces(rip rap,gunite,etc.)on the bed or banks,etc.. Likewise,the recommendation that setbacks from tributaries should be no less than 75 feet also seems excessive in the case of small grassy swales,lesser tributaries that do not carry flow for much of the year,unvegetated drainages,etc. Flexibility and allowances should be made for actual physical conditions in both creek and tributary channels. Site conditions which would warrant such flexibility in offsetting or reducing the recommended 75'or 100'setbacks include creek or tributary sections with lower quality of habitat,adjacent developed land uses,stable embankment conditions,extent of existing or expected disturbances,type of vegetative cover,etc. 5142EI RANKLIN DRIVE,SUITE B PLEASANTON,CALIFORNIA 94588-3355 PHONE(510)225-0690 FAX(510)225-0698 OFFICES: FAIRFIELD PLEASANTON ROSEVILLE SACRAMENTO SAN JOSE SANTA ROSA Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 2 On page 57,it is also noted that erosion and hydrologic considerations"may allow"for flexibility in determining the biological setbacks for tributaries in terms of both distance and offsetting on the different sides. The wording of this sentence should be amended to read: "should allow". Additionally,this level of flexibility should also be applied to setbacks along Tassajara Creek as well as tributaries. Another concern is the procedure by which setbacks are measured. Based on the description on page 26 and in Figure 1,the recommendation that setbacks be measured from the outermost limit of a stream meander is excessive. In light of the loss of developable land associated with this setback approach,it would be worthwhile to look into providing stabilization measures for such creek sections and allowing land areas around meanders to be used if an adequate setback from the top of bank is provided. In addition,the data in this Program does not conclusively document that these meanders are particularly dynamic. In light of the fact that the upper reach of the channel is deeply incised and contains what presently appears to be stable vegetative cover,it is questionable whether the setback distances recommended are appropriate. It is suggested that aerial photos taken over the last 40-50 years of Tassajara Creek should be analyzed to accurately determine whether these meanders have been actively changing over this time frame. A more detailed and site specific analysis might be considered to attempt to identify where future creek meanders might occur in order to determine if a flat 100'setback is really justified. The additional 30' private development buffer required by EBRPD in areas outside their actual area of maintenance is an excessive requirement. The text on page 13 states that the private buffer serves a"specific purpose",however,its purpose is never identified. The management of the overall corridor and private buffer could become problematic as it is recommended that Zone 7,EBRPD and various HOAs be responsible for different areas. There is the potential for conflict with respect to the level of maintenance and area of coverage between these different entities. Each segment of the corridor should be managed by one entity to provide for a consistent level of maintenance. If this requirement remains in the Program,affected landowners should receive additional park or open space land dedication and improvement credits. Other problematic issues deal with the cost,phasing,monitoring,ownership,maintenance and financing of the Program. Project construction is suggested to not begin until all required permits have been secured and,in the event that construction is phased,permits should be secured for the entire project before construction begins in any area. We completely disagree with both of these requirements. Normal practice is for construction activities to typically begin before all permits are secured. Additionally,the proposed requirement to secure all permits for the entire project before construction commences is inconceivable as many years could occur between various development phases of a large project such as Dublin Ranch. There is very little detail provided in the text with respect to costs for establishment and maintenance of revegetated stream corridor areas. A section should be added which addresses specific cost items,unit prices,assumptions,etc. applicable to this Program. On page 14 the document specifies that the City of Dublin is interested in having EBRPD and Zone 7 assume ownership of and manage portions of the stream corridor. However,the text also needs to identify where local trails and trail easements are specified to occur through proposed GONMECorres.:1996160.-nrg4/18/96StreamCumme,ts • Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 3 development areas and along tributaries,as well as who will pay for,own,manage and assume liability for them. What are the ramifications if Dublin Ranch dedicated the stream corridor lands within their property to EBRPD? What would be the impact with respect to future maintenance,monitoring, liability,etc.? Since we are not fully aware of the consequences of dedicating the stream corridor land to EBRPD,we reserve the right to discuss this issue in greater detail in the future. The project scheduling and phasing discussion on page 17 implies that activities along the Tassajara Creek corridor and tributaries will be phased. However,no further detail is provided as to how various items will work together,what items are needed as related to the entire reach of the creek, how costs of improvements would be paid for and shared in a benefit analysis, etc. Furthermore,on page 69,it is noted that projects are to be phased when the project is too large or costly to execute at one time or when land ownership patterns and project administration necessitate the need for phasing. Phasing is expected to coincide with construction of the flood terrace,trails,and roads in conjunction with adjacent development. The text specifies that phasing would allow the City and landowners to establish procedures for planning,review,permitting, construction,maintenance and monitoring. Exactly how these tasks will be coordinated and whether all landowners must buy into the procedures need to be specifically addressed in the Program. Page 116 mentions that creek improvements will occur by reaches. Does this mean that improvements for each of the three reaches identified will occur at one time with all adjacent landowners"working together"? If improvements are to occur by reach,at what point in the development process would it occur? How funding and reimbursement for improvements would be addressed also needs to be clarified. A Habitat Monitoring Program and a Horticulture Monitoring Program are recommended to be established on p. 113. Please clarify how theses program will be determined and funded. In addition, consideration should be given to merging these two programs since they're not significantly different. Whether the programs will be implemented by individual landowners or on a creek-wide basis also needs to be addressed. Additionally,we have some concerns about specific goals,standards and review times for the habitat and horticulture monitoring programs especially since the Corps will need to approve any program. If goals and standards are included with this program,they should be written generally,not quantitatively,to provide consistency between the two programs. Additionally,any large area of planting,not just 100 or more trees is as specified in the text, should qualify as a representative sample plot. Furthermore, both programs should end if and when all the goals and standards have been achieved. Page 66 of the document specifies that an individual should monitor the establishment of the mitigation plantings for five years. Please clarify how will this position be filled,which agency will be responsible for implementing this action,and how this would be funded. On page 110 it is recommended that a maintenance manual be developed prior to installation of plant materials. Since the purpose of the manual is to provide consistency for all phases,will this document be prepared for all phases at the commencement of the first development project? Also, CONNIECones41996a611a4�g4/15/96St,nmComma,ts Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 4 who will prepare and oversee preparation of the document and how will funding and reimbursement work? Please clarify these and any other related issues. In addition to our primary concerns described above,we would also note the following additional specific comments and questions concerning other elements of the proposed stream corridor restoration program: • This document needs to clearly state that the City of Dublin is the ultimate authority for determining appropriate guidelines for stream restoration. Additionally,the document should provide a general guideline or policy which establishes that the land use goals and objectives of the Eastern Dublin Specific Plan prevail over any conflicting goals,policies and programs that might be prescribed in the Stream Corridor Restoration Program. • With respect to plan review, the text should be revised to state that individual project development plans should be reviewed by EBRPD,Zone 7 and CDF&G only if these entities will become the ultimate owner/manager of the corridor within an individual landholding or, as in the case of CDF&G, an existing natural feature occurs which is protected by their agency(e.g.with respect to stream alteration). • The California Department of Fish and Game must review and approve this document prior to City adoption in order to gain their acceptance of the policies and procedures recommended within. This would help to reduce potential complications later in the permitting,construction monitoring and maintenance phases as future projects are proposed for development. In particular,we are concerned that the basic trail design on both sides of the creek may not be in conformance with CDF&G desires. • A map should be included in the document identifying all major and minor tributaries of Tassajara Creek referenced in the text.It is confusing as to what constitutes a major/minor tributary and where it is specifically located within Eastern Dublin. • With regards to the various trail recommendations,this document is not the appropriate vehicle to determine where local trails should occur in Eastern Dublin. Trail locations have been identified in the Specific Plan as well as the City's Parks and Recreation Master Plan and in some cases the recommendations in this document are not consistent with them. In the instance of Figure 11-Local Trail,the condition shown does not appear to exist within any stream or tributary corridor areas,but rather,through other development areas. • Trail access points and staging area amenities as specified on page 47 and 49 are excessive, both in quantity and type. • The various exhibits and the text should be revised to show local and regional trails maintenance roads restricted to only one side of a corridor. This action would help to further preserve and protect the habitat of the creek and tributaries. Specific Plan Policy 6-13 also identifies this approach for trails as a desired objective. CONNIECorres_19%:16 340 g4/18/96Sfre ,Comments Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 5 • Figure 10 illustrates only one setback from the trail,that being on the creek side. However,in instances where no private buffer occurs,a minimum setback should be shown on the side which would abut development. • On page 48,it is suggested that the 30'structure setback be widened to allow for the regional trail to meander. The justification as why additional meandering of trails beyond this setback limit needs to be clearly documented in the text. Rather than widening the structure setback, we suggest that the trail should be permitted to meander throughout the 100'wildlife setback within reasonable safety limits. • The regional trail/maintenance road should be included within the wildlife setback area such as the local trail is shown. In not all instances will the hydrologic/structural setback exceed that of the wildlife setback as shown on Figure 5. Also on Figure 5,as is typical of much of the upper reach,shouldn't the top of bank really start at the corner of the lower bench and not that at the upper bench? • On page 48,last paragraph,it is stated that the regional trail/maintenance road should cross the creek at the staging area. Given the density of vegetation in that area,it would be worthwhile to explore alternative locations upstream or downstream for constructing the crossing. The existing crossing at the staging area is fine for pedestrians but would have to be reconstructed to accommodate vehicles and the impacts would be significant. The specific site for crossings should not be locked in as part of this Program. • Pages 65-66 specify that no mitigation credits should be applied to street or landscape trees planted within the stream corridor as part of restoration efforts. In particular,trees planted • within the additional 30' private development buffer, if present,should receive mitigation credits or park/open space credit. This text for this section should also require that tree plantings be the same species as those removed or compatible with those tree species planted within the adjacent stream corridor areas. • The recommendation under Section 3.3.5 on page 16 that all riparian trees be replaced at a 3:1 ratio regardless of DBH is excessive,particularly in the case of thickets of numerous small- stemmed trees such as willows. In some cases,a 3:1 replacement for a small but dense thicket could result in an inordinately high mitigation requirement. We recommend that in the case of dense, small-stemmed thickets of riparian trees that the acreage of vegetation impact be replaced on a 3:1 basis. Given the typically rapid growth of these species,this mitigation approach will result in full compensation for the habitat loss within a relatively short period of time. The last sentence in the paragraph should specifically exclude,by species name,invasive non-native trees such as tree-of-heaven,black locust,eucalyptus,etc. These invasive non- native trees should be excluded from the 3:1 replacement requirement. • In the last paragraph on page 33,the text states that a 200 foot wide corridor is recommended by CDF&G where an incised channel disappears under a bridge crossing. What specifically does this mean? How can there be a 200 foot wide corridor under a bridge?-Specific documentation as to the justification for this CDF&G guidelines needs to be provided. CONNIComes_1996:16034.&g4/18/96S e:mCommeMI Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 6 • Under the Specimen Tree Protection item on page 5,the text mentions that any existing native vegetation should be protected. This conflicts with page 65 of the text and page 2 of the checklist of Special Submittal Requirements for tentative subdivision maps which only protect trees. Additionally,the policy associated with this paragraph specifies that tree disturbance or removal should be"minimized." This sentence should be rewritten to apply only to native trees considered healthy as described in other sections of the Stream Corridor Restoration Program. • On page 66,the text notes that springs,seeps and ponds occurring within a creek or tributary corridor should be maintained and protected. It should be qualified that this should occur only if these features fall under the jurisdiction of the Corps of Engineers or CDF&G which is consistent with the Eastern Dublin Specific Plan Policy 6-9. • The basis for the recommendation that creek crossings should be approximately every 2000 feet as noted on page 49 needs to be stated. Rather than dictating a certain distance attempts should be made to locate creek crossings where creek bank widths are reasonable,existing native vegetation is limited,and embankment conditions are relatively stable. Additionally,if crossings are to be placed above future potential creek meander sections anticipated to be moving down the creek,as noted on page 50,the engineering and construction costs of such a crossing would likely be prohibitive. • Page 59 notes that soil compaction during the installation of bioengineering structures is discouraged,however,normal construction practices to prepare the site prior to improvements requires soil compaction to occur. Bioengineering structures and installation techniques should be discussed in greater detail. • Under Habitat Restoration on page 5,Policy 6-22 states that"all areas of disturbance should be revegetated as quickly as possible." However,associated text states that restoration should "emphasize prompt revegetation." The text should be compatible with the verbiage of this policy. • The requirement for soils testing,particularly with respect to agriculture suitability,seems extreme and costly for a project of this type. • The text on page 109.specifies that ground or well water should not be used as a source for temporary irrigation uses,however,no documentation is provided as to whether ground water quality problems actually exist. This source is already used by existing vegetation which has access to the groundwater table. Additionally,the document on page 112 suggests that the irrigation system be monitored and repaired monthly which seems really excessive. • When will HEC-H modeling prepared by the City or Zone 7 be completed? This will affect when property owners undertake their site specific HEC-II analysis. • We question whether a biological corridor connections map is actually necessary as identified on page 2 of the checklist of Special Submittal Requirements for Tentative Map. This map is basically a duplication of information shown on Specific Plan maps. In addition, the requirement to provide landscaping plans adjacent to Tassajara Creek or tributaries as described CONNIE:Corres.:1596:160v.Hg4/1e/96so-camcommenis Carol Cirelli 16034-0 Eastern Dublin Stream Corridor Restoration Program Page 7 on page 3 of checklist of Special Submittal Requirements for Tentative Map is also questionable. Most of the information to be illustrated on this map is already shown on other required maps. It is our understanding that other landowners have expressed concerns with the proposed program. Based on this as well as the extensive list of concerns we have compiled,a landowners meeting to address these issues would seem to be particularly important before sending this package on to the Planning Commission and Council. Please let us know if there is interest in having such a meeting. Thank you for the opportunity to comment on the City's proposed Eastern Dublin Comprehensive Stream Restoration Program and of your consideration for our comments and questions. Sincerely, MACKAY �&y'SOMPS cae David W.Chadbourne cc: Eddie Peabody,Community Development Director T.Fairfield J.Tong M.Inderbitzen R.Andrade R.Harris D.Stephens L.Berry CONN1:Cartes.:19%.16016-0 a/18/965treamCommmts