HomeMy WebLinkAbout4.12 Exhibit A to the Resolution Full PacketDRAFTGREEN STORMWATER INFRASTRUCTURE PLAN
1DRAFTAcknowledgements City of Dublin Green Stormwater Infrastructure Plan
City of Dublin
GREEN STORMWATER INFRASTRUCTURE PLAN
Acknowledgements
This Plan has been developed to meet mandates in the Municipal Regional Stormwater National Pollutant
Discharge Elimination System Permit, Order No. R2-2015-0049, NPDES Permit No. CAS612008 issued by the
San Francisco Bay Regional Water Quality Control Board on November 19, 2015. This Plan was presented to the
Dublin City Council on June 18, 2019 and adopted Resolution XX-19 is included at the end of this document.
The following individuals provide substantial input and advice during the development of this Plan:
City Council
David Haubert, Mayor
Melissa Hernandez, Vice-Mayor
Arun Goel, Councilmember
Jean Josey, Councilmember
Shawn Kumagai, Councilmember
City Staff – Key Supporting
Chris Foss, City Manager
Linda Smith, Assistant City Manager
Andrew Russell, Public Works Director
Laurie Sucgang, Assistant Public Works Director/City Engineer
Obaid Khan, Transportation and Operations Manager
Michael Boitnott, Capital Improvement Projects Manager
Dean McDonald, Public Works Maintenance Superintendent
City Staff – Lead and Contact for the Plan
Shannan Young, Environmental Coordinator
Project Consultant - Geosyntec Consultants
Kelly Havens, P.E., Senior Engineer
Lisa Austin, P.E., Principal
Elai M. Fresco, P.E., Senior Staff Engineer
Austin M. Orr, P.E., Engineer
Alameda Countywide Clean Water Program Support
Jim Scanlin, Program Manager
Horizon Water and Environment, LLC
Laura Prickett
2 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Table of Contents
Table of Contents
Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1 . Introduction .........................................................................5
1.1 Statement of Purpose .................................................................5
1.2 Municipal Regional Stormwater NPDES Permit ............................................6
1.3 Green Stormwater Infrastructure .......................................................8
1.4 Benefits of Green Stormwater Infrastructure ..............................................13
2 . Prioritizing and Mapping Potential Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
2.1 Private GSI Projects .................................................................15
2.2 Public GSI Projects .................................................................16
3 . Green Stormwater Infrastructure Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3.1 GSI Primary Goals .................................................................18
3.2 Early Implementation, or “No Missed Opportunities” ......................................19
3.3 Potential Project Cost Analysis ........................................................19
3.4 Concept Plan Development ..........................................................20
3.5 Creation of Typical Stormwater Design Details ............................................21
3.6 Work with Private Developers .........................................................21
3.7 Municipal Regional NPDES Permit General Fund Reserve ...................................21
4 . GSI Program Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
4.1 Legal Mechanisms for Implementation ..................................................22
4.2 General Guidelines and Implementation Checklists ........................................22
4.3 Operations and Maintenance, Inspection and Enforcement ..................................23
4.4 GSI Requirements in Planning Documents ...............................................23
5 . Evaluation of Funding Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
6 . Conclusion and Next Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Appendix A: City of Dublin Green Infrastructure Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Appendix B: Municipal Regional Stormwater NPDES Permit Green Infrastructure Plan Requirements . .36
Appendix C: City of Dublin Gi Plan Framework Analyses Methodology Memorandum . . . . . . . . . . . . . .37
Appendix D: Project Cost Analysis Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Appendix E: Potential Project Concept Plans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69
Appendix F: City of Dublin Typical Stormwater Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Appendix G: General Guidelines and Implementation Checklists for GSI Projects . . . . . . . . . . . . . . . . . .83
Appendix H: Funding and Financing Strategy Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Appendix I: Resolution XX-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124
3DRAFTTable of Contents City of Dublin Green Stormwater Infrastructure Plan
List of Figures
Figure 1 Relationship between impervious surfaces and stormwater runoff
Figure 2 How Green Stormwater Infrastructure Improves Water Quality
Figure 3 Green Stormwater Infrastructure Projects installed in Dublin through 2020
Figures 4a & 4b Potential Green Stormwater Project Locations
Figure 5 Downtown Dublin Streetscape Master Plan Land Area
List of Tables
Table 1 Green Stormwater Infrastructure Compared to Low Impact Development
Table 2 Comparison of C.3 Regulated Projects with Green Stormwater Infrastructure Plan Requirement
Table 3 Estimate of Private Development Retrofit of Impervious Surface Area
Table 4 Design and Construction Cost Per Unit Acre Summary Statistic
Table 5 O&M Annual Cost Factors for GSI Project Types
Acronyms and Abbreviations
ACCWP Alameda Countywide Clean Water Program
BASMAA Bay Area Stormwater Management Agencies Association
CalTrans California Department of Transportation
CIP Capital Improvement Project
EPA Environmental Protection Agency
FY Fiscal Year
GI Green Infrastructure
GIS Geographic Information System
GSI Green Stormwater Infrastructure
LID Low Impact Development
MRP Municipal Regional Stormwater NPDES Permit
NPDES National Pollutant Discharge Elimination System Permit
O&M Operations and Maintenance
PCBs Polychlorinated Biphenyls
P3s Public-Private Partnerships
TMDL Total Maximum Daily Load
Water Board San Francisco Bay Regional Water Quality Control Board
4 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Executive Summary
EXECUTIVE SUMMARY
The purpose of the City of Dublin’s (City) Green Infrastructure Plan (referred to hereinafter as the Green
Stormwater Infrastructure Plan) is to describe how the City will meet requirements specified in the Municipal
Regional Stormwater National Pollutant Discharge Elimination System Permit (MRP), Order No. R2-2015-
0049, NPDES Permit No. CAS612008 issued on November 19, 2015. The City is one of 76 co-permittees in
the San Francisco Bay Area that are regulated under the MRP. Provision C.3 of the MRP requires Permittees to
develop and implement long-term Green Stormwater Infrastructure (GSI) Plans to show how cities will transform
their storm drainage system from traditional “gray” stormwater infrastructure which rapidly collects and discharges
stormwater to local creeks, to green stormwater infrastructure which slows stormwater flow by directing it to
vegetated systems where possible. The MRP requires the GSI Plan to mitigate for the effects of urbanization, in
general, on receiving water quality, and also to reduce mercury and polychlorinated biphenyls pollutant loads to
San Francisco Bay. In addition to improving water quality, GSI will be designed so that it offers environmental
benefits such as improvements to bike and pedestrian safety, reduce localized flooding, provide carbon sequestration
opportunities, and mitigate for the urban heat island effect. This GSI Plan demonstrates how the City is meeting
MRP requirements and intends to use GSI to enhance the urban environment.
5DRAFTIntroduction City of Dublin Green Stormwater Infrastructure Plan
1. INTRODUCTION
1.1 Statement of Purpose
The purpose of this Green Infrastructure Plan (hereinafter referred to as the Green Stormwater Infrastructure Plan)
is to guide the identification, implementation, tracking, and reporting of green infrastructure projects within the
City of Dublin (City), in accordance with the Municipal Regional Stormwater Permit (MRP), Order No. R2-
2015-0049, adopted by the San Francisco Bay Regional Water Quality Control Board on November 15, 2015.
This Green Stormwater Infrastructure (GSI) Plan has been developed to comply with Green Infrastructure Plan
requirements in Provision C.3.j of the MRP, which states in part:
The Plan is intended to serve as an implementation guide and reporting tool during this and subsequent
Permit terms to provide reasonable assurance that urban runoff TMDL wasteload allocations (e.g., for
the San Francisco Bay mercury and PCBs TMDLs) will be met, and to set goals for reducing, over the
long term, the adverse water quality impacts of urbanization and urban runoff on receiving waters.
For this Permit term, the Plan is being required, in part, as an alternative to expanding the definition
of Regulated Projects prescribed in Provision C.3.b to include all new and redevelopment projects
that create or replace 5,000 square feet or more of impervious surface areas and road projects that
just replace existing imperious surface area. It also provides a mechanism to establish and implement
alternative or in-lieu compliance options for Regulated Projects and to account for and justify Special
Projects in accordance with Provision C.3.e.
Over the long term, the Plan is intended to describe how the Permittees will shift their impervious
surfaces and storm drain infrastructure from gray, or traditional storm drain infrastructure where runoff
flows directly into the storm drain and then the receiving water, to green—that is, to a more-resilient,
sustainable system that slows runoff by dispersing it to vegetated areas, harvests and uses runoff,
promotes infiltration and evapotranspiration, and uses bioretention and other green infrastructure
practices to clean stormwater runoff.
The topics discussed in this GSI Plan include:
• MRP requirements
• Green stormwater infrastructure definition and associated benefits
• Explaining how the City identified and mapped potential projects
• A description of the City of Dublin’s GSI goals
• GSI Program implementation efforts
• Evaluation of funding and finance opportunities
• Conclusion and next steps
6 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Introduction
1.2 Municipal Regional Stormwater NPDES Permit
The City of Dublin is a co-permittee of the Municipal Regional Stormwater NPDES Permit (MRP), Order No.
R2-2015-0049, adopted by the San Francisco Bay Regional Water Quality Control Board on November 15, 2015.
The MRP applies to 76 municipalities and flood control agencies that discharge stormwater to the San Francisco
Bay, collectively referred to as Permittees.
A new addition to the MRP in the November 2015 permit reissuance is the requirement for Permittees to develop
a Green Stormwater Infrastructure Plan. Permittees are required to use the GSI Plan to guide the identification,
implementation, tracking and reporting of GSI projects within each jurisdiction. Both public and private projects
are required to be tracked and reported. GSI can be applied at the watershed level, or it can be applied to a parcel
or a street. Examples of types of GSI include bioretention areas, pervious pavement, tree well filters, green roofs,
tree planting, rainwater capture and use, and tree planting. These examples are described in Section 1.3 of this
document.
The MRP has also mandated incorporation of low impact development (LID) practices on both public and private
property that meet certain size thresholds (“Regulated Projects”) since 2011. LID is a subset of the larger scale (i.e.
watershed level) GSI practices that is applied at the site level (see Table 1). LID practices that have been required
for Regulated Projects as prescribed in Provision C.3 of the MRP include site design, pollutant source controls,
stormwater treatment, and flow control facilities. The most common type of LID stormwater treatment practice
installed at projects in Dublin has been bioretention areas, as typified in the bioretention areas installed along
Tassajara Road. It is anticipated that bioretention areas will continue to be the most common type of LID/GSI
stormwater treatment facilities installed in Dublin.
Bioretention area on west side of Tassajara Road at Rutherford Drive.
7DRAFTIntroduction City of Dublin Green Stormwater Infrastructure Plan
Table 1 | Low Impact Development Compared to Green Stormwater Infrastructure
Category Definition Applies To
Low Impact Development
(LID)
The goal is to reduce runoff and mimic a site’s
predevelopment hydrology.
Preserves and recreates natural landscape features.
Minimizes imperviousness to create functional
and appealing site drainage.
Infiltrates, stores, detains, facilitates
evapotranspiration and/or biotreats stormwater
runoff close to its source.
LID is a subset of green stormwater infrastructure
applied at the site scale.
MRP Provision C.3 Regulated
Projects (public and private).
Green Stormwater
Infrastructure (GSI)
Infrastructure that uses vegetation, soils, and
natural processes to manage water and create
healthier urban environments.
At the scale of a city or county, GSI refers to the
patchwork of natural areas that provides habitat,
flood protection, cleaner air, and cleaner water.
At the scale of a neighborhood or site, GSI refers
to stormwater management systems that mimic
nature by soaking up and storing water.
Any public or private project,
above and beyond Provision
C.3 Regulated Projects,
for which it is feasible to
incorporate GSI elements, and
for which funding is available
to construct and maintain the
project. Projects are prioritized
based on water quality and
other social and environmental
benefits.
Both GSI and LID practices are intended to mitigate the impacts of development on the water quality of local
creeks and San Francisco Bay. However, GSI requirements are distinct from the LID mandates for Regulated
Projects. Regulated Project requirements automatically take effect once certain size thresholds are met. In contrast,
there is no size threshold for GSI projects (see Table 2).
Table 2 | Comparison of C.3 Regulated Projects with Green Stormwater Infrastructure Plan Requirement
Impervious Surface Threshold Requirement
C.3 Regulated Projects 5,000 square feet (Special Land Use – parking
lots, restaurants, retail gas outlets, automotive
related)
10,000 square feet (all other land uses)
LID Site design, pollutant
source controls, and on-site
stormwater treatment.
C.3 Regulated Projects 1 acre (all land uses)LID Site design, pollutant
source controls, on-site
stormwater treatment,
and hydromodification
management (flow control).
Green Stormwater
Infrastructure projects
No size threshold. Plan required to prioritize
projects to demonstrate how Permittees will shift,
over time, from gray to green infrastructure.
Site design, stormwater
treatment, tree planting,
infiltration, capture and use.
8 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Introduction
The San Francisco Bay Regional Water Quality Control Board (Water Board) included the GSI requirements in
the reissuance of the MRP for several reasons:
• In lieu of requiring GSI for all road projects that just replace existing impervious surface and as an alternative
for lowering the size threshold for Regulated Projects;
• To mitigate for the impacts of urbanization on water quality on local creeks and San Francisco Bay; and
• To demonstrate with reasonable assurance, that urban runoff total maximum daily load (TMDL) wasteload
allocations for mercury and polychlorinated biphenyls (PCBs) will be met. For more information on the
TMDL wasteload allocation, refer to the Green Infrastructure Framework approved by City Council on June
20, 2017 provided in Appendix A.
A milestone in the development of the GSI Plan was City Council’s adoption of Resolution 77-17 establishing a
Green Infrastructure Framework on June 20, 2017 (Appendix A). The Green Infrastructure Framework described
the environmental issues that are addressed with the development of a GSI Plan as well as funding considerations.
The main driver for the GSI Plan is to remove pollutants from stormwater runoff, but GSI can also help alleviate
localized flooding, can assist in reducing the urban heat island effect, can enhance carbon sequestration in the
urban environment and can be incorporated into the streetscape in the form of bioretention areas next to streets
to enhance the bicycle-pedestrian environment. In addition to funding considerations, prioritization of projects
which may potentially include GSI will evaluate the multiple benefits that may be achieved to maximize the
impact of dollars spent per project. As discussed in Section 5, this MRP requirement is an unfunded mandate and
currently there is no dedicated funding stream to design, construct, or maintain these projects and considerable
capital will be required to implement this program. Explorations of funding options are underway, and this
GSI Plan is a continuation of the Green Infrastructure Framework effort. For a complete list of MRP GSI Plan
requirements, please refer to Appendix B.
1.3 Green Stormwater Infrastructure
When land is developed, pervious surfaces such as natural areas or vacant lots which allow water to infiltrate
into the soil are converted to impervious surfaces. Impervious surfaces are hard surfaces which prevent water
from infiltrating into the soil, causing it to run off instead. The increase in impervious surfaces such as roads
and rooftops that are associated with development, increases the speed and volume at which rain or stormwater
runs off the land and into the storm drain system since stormwater that otherwise would have infiltrated into the
ground can no longer do so (Figure 1). Activities associated with land development such as additional cars on the
road or more trash generating activities, cause an increase in pollution deposited on the land which is picked up
and washed off impervious surfaces when it rains.
Figure 1 | Relationship Between Impervious Surfaces and Stormwater Runoff. Source: EPA (2003)
9DRAFTIntroduction City of Dublin Green Stormwater Infrastructure Plan
Green stormwater infrastructure (GSI) is designed to improve stormwater runoff quality prior to discharging it to
local creeks and San Francisco Bay. GSI is engineered or man-made infrastructure that is based on natural processes
to manage stormwater runoff. In addition to reducing pollutants transported to creeks and San Francisco Bay,
GSI systems provide a variety of other benefits. The retention and infiltration of stormwater can reduce localized
flooding, reduce flows that may cause erosion in creek channels, decrease downstream flows to mitigate impacts of
sea level rise, and recharge groundwater aquifers. Figure 2 depicts how green stormwater infrastructure can retain
and infiltrate stormwater runoff. The multiple benefits of GSI are more fully explained in Section 1.4 below.
Figure 2 | How Green Stormwater Infrastructure Improves Water Quality. Credit, City of Fremont
How Green Stormwater Infrastructure Improves Water Quality
In urban areas, stormwater runoff flows off hard surfaces, carrying pollutants such as vehicle fluids, litter, and pet waste into
local creeks and the San Francisco Bay. Green stormwater infrastructure helps remove pollutants by using trees and engineered
landscape-based facilities constructed with special soils, gravel and vegetation. Stormwater runoff is slowed as it passes through green
stormwater infrastructure, allowing for pollutant removal by processes such as filtration, microbial action, and plant uptake.
Bioretention areas are planted
depressions designed to
absorb and slow stormwater
runoff, allowing vegetation and
specialized soil to remove silt
and pollutants. Stormwater
runoff that is not used by the
plants or absorbed into the
ground flows to the storm drain
system via an under drain pipe.
Common Green Stormwater Infrastructure Facilities
Swales are engineered
to maximize the time
stormwater spends in
the depressed, vegetated
channel, allowing the
vegetation to remove silt
and pollutants.
Storm drains are designed to convey stormwater in times of
heavy rainfall to reduce flooding. Without green stormwater
infrastructure, stormwater flows untreated from storm drains
directly to local creeks and San Francisco Bay.
Tree well filters can turn a street tree into
green stormwater infrastructure. The trees
grow in specially designed soils which
allow pollutants from streets and parking
lots to be removed naturally. In addition,
stormwater is intercepted by the tree
canopy, reducing stormwater runoff rates.
10 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Introduction
Scale of Green Stormwater Infrastructure
Green stormwater infrastructure can be applied at various scales, from a street or a parcel to a larger regional area.
Typically, GSI is designed to capture and treat 80 percent of the total stormwater runoff over the life of the project.
• Green streets . A green street is designed
to redirect roadway runoff from typical
gray infrastructure, such as storm drain
pipes, to green stormwater infrastructure.
The street may be designed such that
stormwater runoff flows into vegetated
areas or infiltrates into the ground
through permeable pavement. An
example of a green street retrofit project
in Dublin is Golden Gate Drive.
• Parcel-based project . Parcel-based
projects mitigate stormwater impacts
by reducing stormwater runoff through
capture and use and/or by infiltrating
and treating stormwater on-site before
it enters the storm drain system.
Bioretention areas constructed in
parcel-based projects typically capture
stormwater runoff from parking lots,
rooftops and other impervious surfaces
generated on the parcel itself. It is also
possible to design a parcel-based GSI
facility such that it collects and treats stormwater runoff from impervious surfaces immediately adjacent to the
parcel (e.g. stormwater runoff from the adjacent roadway). An example of a parcel-based project in Dublin is
Persimmon Place.
• Regional project . Regional projects
are large-scale stormwater capture and
treatment facilities that are intended
to collect and treat runoff from a large
drainage area. These projects are often
the most cost-effective due to multiple
benefits achieved and economies of
scale. An example of a regional project
in Dublin is the Dublin Ranch regional
water quality basin.
Bioretention area at Golden Gate Drive and St. Patrick Way
Bioretention area at Persimmon Place
Dublin Ranch Regional Water Quality Basin
11DRAFTIntroduction City of Dublin Green Stormwater Infrastructure Plan
Examples of Green Infrastructure
• Bioretention areas . Bioretention areas, or rain gardens, function as soil
and plant-based filtration devices that remove pollutants through a variety of
physical, biological, and chemical processes. These facilities normally consist
of a ponding area, organic layer or mulch layer, planting soil, and plants.
Bioretention areas are designed to distribute stormwater runoff evenly along
a ponding area and slowly infiltrate stormwater into the soil. Bioretention
areas have been the most commonly installed type of GSI in Dublin to date.
An example of a parcel-based bioretention area in Dublin is provided at Aster
Apartments.
• Flow-through planters. Flow-
through planters are designed to treat
and detain runoff without allowing
seepage into the underlying soil. This
type of GSI facility is usually constructed
with a concrete structural planter wall.
Stormwater treatment is achieved through
the same mechanisms as bioretention
areas except without infiltration. They can be used next to buildings and
other locations where soil moisture is a potential concern. Flow-through
planters typically receive runoff via downspouts leading from the roofs
of adjacent buildings. Flow-through planters typically receive runoff via
downspouts leading from the roofs of adjacent buildings, however, they
can also be set level with the ground and receive sheet flow. An example
of a flow-through planter is provided by the National Association of City
Transportation Officials.
• Tree well filters . Tree well filters are useful in settings where available space is limited. They may be installed
along urban sidewalks, but they are highly adaptable and can be used in most development scenarios. In urban
areas, tree well filters can be used in the design of an integrated street landscape – a choice that transforms
isolated street trees into stormwater filtration devices. Modular suspended pavement system products, such as
Silva Cells, may be used for tree well filter construction and filled with biotreatment soil. An example of a tree
well filter may be seen at the Boulevard.
Bioretention area at Aster
Apartments in Dublin
Tree well filter being constructed
using Silva Cells at the Boulevard.
Installed tree well filter using Silva Cells at the Boulevard.
Flow-through planter from the
National Association of City
Transportation Officials
12 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Introduction
• Pervious pavement . Pervious pavement includes pervious concrete, porous asphalt, pervious or permeable
concrete pavers, permeable interlocking concrete pavement (PICP), and grid pavements such as turf block
and grasscrete. Pervious paving is typically used for areas with light vehicle loading and lightly trafficked
areas, such as automobile parking areas, but can also be designed to withstand heavier traffic loads. The term
pervious paving describes a system comprised of a load-bearing, durable surface constructed over a subbase/
base structure typically consisting of compacted, open-graded aggregate rock. The subbase layer temporarily
stores stormwater prior to infiltration into the soil or drainage to a controlled outlet. An example of pervious
pavement in Dublin is the Grasspave2 parking area at the Wave at Emerald Glen Park.
• Green roofs . A green roof can be either extensive, with three to seven
inches of lightweight substrate and a few types of low-profile, low-
maintenance plants, or intensive with a thicker (up to 48-inches)
substrate, more varied plantings, and a more garden-like appearance.
Green roofs clean the stormwater that lands on the surface of rooftops
before it flows to the storm drain system. Both intensive and extensive
green roof systems contain layers of protective materials to convey
water away from the roof deck. Starting from the bottom up, a
waterproof membrane is installed, followed by a root barrier, a layer of
insulation (optional), a drainage layer, a filter fabric for fine soils, the
engineered growing medium or soil substrate, and the plant material. In addition to improving stormwater
quality, green roofs can increase the longevity of roofing membranes, reduce noise and air pollution, help
insulate the building, and increase urban biodiversity by providing
habitat for wildlife such as butterflies. An example of a green roof can
be seen at the West Elm shop in Emeryville.
• Rainwater Capture and Use . Rainwater capture and use
systems are engineered to store a specified volume of water with no
discharge until this volume is exceeded. Storage facilities that can be
used to capture rainwater include above-ground or below-ground
cisterns, open storage reservoirs (e.g., ponds and lakes), and various
underground storage devices (tanks, vaults, pipes, arch spans, and
proprietary storage systems). Rooftop runoff is the stormwater most
often collected in capture and use systems because it often contains
lower pollutant loads (i.e. is less dirty) than surface runoff from streets or
parking lots, and it provides accessible locations for collection. Rainwater
Grasspave2Grasspave2 installed at The Wave at Emerald Glen Park
Large Scale and Commercial Rainwater
Capture and Use. Source: The Renewable
Energy Hub
Green roof at the West Elm store in
Emeryville, CA
13DRAFTIntroduction City of Dublin Green Stormwater Infrastructure Plan
can also be stored under hardscape elements, such as paths and walkways, by using structural plastic storage
units, such as RainTank, or other proprietary storage products.
• Trees . Trees perform a variety of functions that reduce the amount of stormwater runoff and improve water
quality. Leaf canopies intercept and hold rainwater on the leaf surface, preventing it from reaching the
ground and becoming stormwater runoff. Root systems create voids in the soil that facilitate stormwater
infiltration into the ground. Trees also
absorb and transpire large quantities
of groundwater, making the soil
less saturated, which allows more
stormwater to infiltrate. Through
the absorption process, trees remove
pollutants from stormwater. Tree
canopies shade and cool paved areas,
reducing the urban heat island effect.
Dublin has demonstrated the high
value it places on trees by becoming
an Arbor Day Foundation Tree City
USA Community. Trees are planted
throughout the community, as
exemplified in the street trees shown
here on Rutherford Drive.
1.4 Benefits of Green Stormwater Infrastructure
According to the United States Environmental Protection Agency, green
stormwater infrastructure (GSI) is a cost-effective, resilient approach to
managing wet weather impacts that provides many community benefits.
While single-purpose gray stormwater infrastructure—conventional
piped drainage—is designed to move urban stormwater away from the
built environment, green stormwater infrastructure infiltrates and treats
stormwater at its source while delivering environmental, social, and
economic benefits. Some of the benefits of GSI are discussed below.
• Improved water quality . As stormwater flows over impervious
surfaces such as concrete or asphalt, pollutants that are on those
surfaces are picked up and carried to the storm drain system where
it flows to local creeks. Green stormwater infrastructure such as
bioretention areas naturally removes pollutants from stormwater prior
to the stormwater runoff flowing into the storm drain system. How
effectively GSI captures a specific pollutant depends on a variety of
factors, including whether the pollutant is associated with particles or
dissolved in stormwater runoff and how the pollutant responds to the
physical, chemical, and microbial action in the facility.
• Restores aquatic habitat . As impervious surfaces such as concrete,
asphalt, and rooftops are added in a community, stormwater that was
Trees along Rutherford Drive
Alamo Creek
14 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Introduction
once able to percolate into the ground instead flows much faster to the storm drain system and local creeks,
which can erode streambanks and scour streambeds. This causes damage to habitats for fish and other aquatic
species. Green infrastructure slows the speed and volume of stormwater flowing to creeks, helping to restore
creek health.
• Mitigate localized flooding . Green stormwater infrastructure can be installed where localized flooding is a
concern. Green stormwater infrastructure is designed to manage the stormwater runoff from small to medium
storm events such that the stormwater runoff is held within the GSI facility and slowly discharged to the storm
drain system or infiltrated into the ground. An added benefit is that the infiltrated stormwater may be able to
recharge groundwater or local creeks.
• Alleviate Urban Heat Island Effect . Urban heat islands are created when natural areas are replaced with
concrete, buildings, and other impervious surfaces that absorb and retain heat. It is anticipated that climate
change will contribute to more frequent, more severe, and longer heat waves during summer months. Planting
trees and using green stormwater infrastructure can help reduce the urban heat island effect by providing shade
and releasing moisture into the atmosphere.
• Improve air quality . Trees and plantings used in GSI facilities remove particulates from the air, helping to
improve local air quality.
• Carbon sequestration . The plants and soils that are part
of GSI facilities can serve to sequester carbon. The main
greenhouse gas that contributes to climate change, carbon
dioxide, is captured and removed from the atmosphere
via tree and plant photosynthesis. Incorporating green
stormwater infrastructure is an additional way to add to
carbon sequestration opportunities.
• Enhance the bicycle-pedestrian environment . GSI
facilities can be used to enhance the bicycle environment
by providing a buffer between cars and bikes, or the
pedestrian environment by shortening the crossing
distance at intersections. Bioretention areas may be placed
to capture and treat stormwater runoff from roadways
or used as bulbouts at intersections. The Amador Valley
Boulevard traffic improvement project is an example.
Separated bike lane with bioretention; source
unknown.
15DRAFTPrioritizing and Mapping Potential Projects City of Dublin Green Stormwater Infrastructure Plan
2. PRIORITIZING AND MAPPING POTENTIAL PROJECTS
Provision C.3.j of the MRP requires Permittees to prioritize and map constructed GSI on both public and private
property. Public and private GSI is required to be installed at projects to mitigate for the effects of urbanization
on water quality, in general, and to reduce mercury and PCBs load reductions to San Francisco Bay, in particular.
Permittees are required to target amounts of existing impervious surface to be retrofitted by 2020, 2030 and 2040
to demonstrate that mercury and PCBs load reductions mandates are achieved. To assist with prioritizing and
mapping of installed, planned and potential GSI projects, City Staff hired Geosyntec Consultants. The mapping
and prioritization work was completed in two phases. The first phase was completed in 2017 prior to the adoption
by the City Council of the Green Infrastructure Framework and the second phase was completed in 2019 as part
of the GSI Plan development.
2.1 Private GSI Projects
In Phase 1 of the project in 2017, all Regulated Projects (primarily private) that had installed GSI facilities
were identified and mapped in an online ArcGIS platform. The ArcGIS platform was developed by the Alameda
Countywide Clean Water Program (ACCWP) in cooperation with the Contra Costa Clean Water Program and
is the method by which Permittees within those two countywide clean water programs are tracking and mapping
Provision C3 Projects. The Regulated Projects with installed GSI, along with known, future Regulated Projects (i.e.
Regulated Projects that were in the development review process) were added to the ArcGIS platform as projects
that would be completed by 2020. To map potential private projects at the 2030 and 2040 timeframes, the City’s
General Plan and specific plans were reviewed to identify where development may occur in Dublin. Figure 3
shows the extent of GSI facilities installed at Regulated Projects in Dublin through the 2020 timeframe and Table
3 provides an estimate of the additional amount of impervious surface area that could potentially be managed
with GSI through private development through 2040. For a complete description of the methodology used, see
the City of Dublin GI Plan Framework Analyses Methodology Memorandum (Memorandum) in Appendix C.
16 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Prioritizing and Mapping Potential Projects
Figure 3 | Green Stormwater Infrastructure Projects Installed in Dublin Through 2020
Table 3 | Estimate of Private Development Retrofit of Impervious Surface Area
Year Green Stormwater Infrastructure Treated Area (Impervious Acres)
By 2020 361.0
2021-2030 80.1
2031-2040 24.6
2.2 Public GSI Projects
Phase 1 of the mapping and identification of potential public GSI project locations included developing a GSI
opportunity analyses methodology and using that methodology to identify potential opportunities for public
retrofit or regional projects. The opportunity analyses methodology used geographic information system (GIS)
data to identify public parcels and/or right-of-way where GSI could feasibly be implemented based on technical
screening criteria. Opportunities for green street and regional GSI facilities were examined. A GIS analysis was
conducted to identify where public parcels overlap with areas that may be physically and hydrologically conducive
to GSI implementation. For a complete description of the opportunity analyses and prioritization method, see
the Memorandum in Appendix C. Phase I also included mapping of public property that had installed green
stormwater infrastructure facilities. These properties are included in Figure 3. The total treated acreage for public
projects installed through 2020 is 54.3 acres.
In Phase 2 of the GSI Plan development, the City refined the potential project locations identified in Phase I by
completing additional desktop analyses to screen out project locations with observed utility conflicts (i.e. gas,
water, sewer) or other incompatibilities (e.g. not enough space to construct GSI). In addition, all city parcels,
regardless of size, were included in the Phase 2 analysis. Whereas the original analysis in Phase I was primarily
Legend
City of Dublin Boundary
Parks Reserve Forces Training Area and Federal Correctional Institution (Federal Jurisdiction)
New / Redevelopment Projects
Private New / Redevelopment Projects, 2003-2020 (361.0 impervious acres treated)
Public New / Redevelopment Projects, 2003-2020 (54.3 impervious acres treated)
*Private New / Redevelopment Projects, 2030 (under construction; 60.7 impervious acres treated as shown on map)
0 2,800 5,600Feet
³
June 2019
Figure 3Green Stormwater Infrastructure Projects Installed in Dublin Through 2020*
17DRAFTPrioritizing and Mapping Potential Projects City of Dublin Green Stormwater Infrastructure Plan
focused on identifying larger parcels or streets with higher pollutant load reductions and/or potential regional
projects, all City owned parcels were included in Phase 2 as a visual reminder to evaluate the feasibility of GSI
on any capital improvement project (i.e. “no missed opportunities”). The resulting potential GSI project location
maps based on the Phase 1 and Phase 2 work is shown in Figures 4a and 4b.
Figure 4a | Potential Green Stormwater Project Locations
Arnold Road,
Central toGleason
Arnold Road, DublinBlvd to Central
Arnold Road,
South ofDublin Blvd
Bent Tree
Drive
Central Parkway,
Arnold to Hacienda
CentralParkway,EastCentral Parkway,
Hacienda to Tassajara
Dublin Blvd,
Arnold toHaciendaDublin Blvd,Doughertyto IHT
DublinBlvd, East
Dublin Blvd,
Hacienda toTassajara
Fallon Road,Gleason toCentral
Fallon Road,North ofGleason
Fallon Road,South ofCentral
Gleason Drive,
Arnold to
Hacienda
Gleason
Drive, East
Gleason
Drive, Eastof Tassajara
Gleason Drive,Hacienda toTassajara
Hacienda
Drive, Centralto Gleason
Hacienda Drive,Dublin Blvdto Central
Hacienda
Drive, Southof Dublin BlvdMartinelliWay, Arnoldto Hacienda
Tassajara
Road, Central
to Gleason
Tassajara Road,
Dublin Blvdto Central
Tassajara
Road, South ofDublin Blvd
Central Parkway,Brannigan to Lockhart
Central Parkway,
Tassajara to
Brannigan
Dublin Blvd,
Tassajara
to Lockhart
Gleason Drive,Branniganto Lockhart
Lochart St,Dublin Blvdto Central
Lockhart St,Central to Gleason
Dublin Corp
Yard & AlCoFire Maint Yard Park andRide Lot
EmeraldGlen Park Passatempo
Park
FallonSports Park
Bray
CommonsPark
TedFairfieldPark
PiazzaSorentoPark
FireStation 18
DevanySquare Park
Alamo
Creek Park
FireStation 17
Hacienda
At I-580 Fallon
at I-580
Legend
Green Infrastructure Retrofit Opportunities
Desktop Feasible GI Project Location
"No Missed Opportunities" Project Location
Project Location In Dublin Ranch Pond Drainage Area
Potential Future Caltrans Partnership Location
Parks Reserve Forces Training Area and Federal Correctional Institution (Federal Jurisdiction)
Dublin City Limit
0 1,500 3,000750Feet
³Notes:1. To identify opportunities for prioritization, the approach described in the "City of Dublin GI PlanFramework Analyses Methodology Memorandum" (Geosyntec, 2017) was used.2. Residential roads are not included as potential retrofit opportunities.
3. All parcel opportunities are city-owned.
4. IHT = Iron Horse Trail.5. Opportunities located within the Dublin Ranch Pond Drainage area ultimately drain to anexisting regional treatment facility.June 2019
Figure 4bPotential Green Stormwater InfrastructureProject Locations
Kolb Park
Dublin Heritage Park & Museums
Iron Horse Trail at AVB
Dougherty Hills Dog Park
Alamo Creek Park
Dolan Park
Mape Park
Shannon Park
Stagecoach Park
Fire Station 16
Senior Center
AVB, San
Ramon toI-680
AVB, York to
Stagecoach
Dublin Blvd,
Alamo Canal
to Sierra
Dublin Blvd,Roys Hill Lane
to Inspiration
RegionalStreet
San Ramon Road,
City Limits
to W Vomac
San Ramon Road,
Silvergate to AVB
San Ramon
Road, Southof AVB
San Ramon
Road, W Vomacto Silvergate
Sierra Court
Stagecoach Road,
City Limits
to Turquoise
StagecoachRoad, Turquoise
to AVB
Village
Parkway
Wildwood
at AVB
Golden Gate /
Saint Patrick
Way Retrofit
AVB, York
to I-680
Legend
Green Infrastructure Retrofit Opportunitites
Early Implementation Project
Conceptual Design Developed
Desktop Feasible GI Project Location
"No Missed Opportunities" Project Location
Regional Treatment Drainage Areas
Dublin City Limit ³
June 2019
Figure 4aPotential Green Stormwater Infrastructure Project Locations
Notes:
1. To identify opportunities for prioritization, the approach described in the "City of Dublin GI Plan
Framework Analyses Methodology Memorandum" (Geosyntec, 2017) was used.2. Residential roads are not included as potential retrofit opportunities.3. All parcel opportunities are city-owned.
^_
^_
^_
0 1,250 2,500625
Feet
Figure 4b | Potential Green Stormwater Project Locations
18 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Green Stormwater Infrastructure Goals
3. GREEN STORMWATER INFRASTRUCTURE GOALS
MRP Provision C.3.j Green Infrastructure Planning and Implementation is an unfunded mandate. However, it
requires Permittees to develop a mechanism to prioritize and map areas for potential and planned GSI projects,
on both public and private property, that may be implemented by 2020, 2030, and 2040. The timeframes in
Provision C.3.j are consistent with the timeframes and requirements in Provision C.11 (Mercury Controls) and
Provision C.12 (PCBs Controls) of the MRP. The map of currently installed and planned Regulated Projects
through 2020 required by Provision C.3.j is included in Figure 3 of the preceding section. Table 3 in the preceding
section shows an estimate of the potential future GSI anticipated to be installed on private Regulated Projects by
2030 and 2040 based on the City’s General Plan and Specific Plans. This section of the GSI Plan will describe the
City of Dublin’s GSI retrofit goals.
3.1 GSI Primary Goals
Goal 1: PCBs and mercury load reduction . Provision C.11 and C.12 of the MRP stipulate that green infrastructure
is used to achieve specific PCBs and mercury pollutant loads reductions across the San Francisco Bay Area. Based
on preliminary data, it appears that the City of Dublin should meet its share of green stormwater infrastructure
load reduction mandates by implementing Provision C.3, New and Redevelopment Standards, of the MRP. If
development proceeds as historical trends indicate it should, then Dublin should achieve its 2020 and 2040
population-based GSI PCB and mercury load reduction requirements solely through installation of private GSI.
Goal 2: Mitigate for the impacts of urbanization on water quality . Recognizing that Provision C.3.j of the
MRP stipulates that GSI be installed over the long term to mitigate for the impacts of urbanization on water
quality in general, and that the GSI plans are intended to demonstrate how Permittees will gradually shift from
traditional gray infrastructure to green stormwater infrastructure over time, the City intends to incorporate GSI
in its capital improvement projects to the maximum extent practicable and as funding allows. The City recognizes
that water quality improvements, as well as complete street benefits such as traffic calming, improved bicycle and
pedestrian safety, and increased green space for climate change adaptation are all benefits of GSI.
However, the City cannot commit to specific retrofit projects that are not in the approved capital improvement
project (CIP) plan or have no funding for the addition of the GSI. The City’s CIP plan and associated budget is
completed on a five-year cycle and is approved by City Council. The current CIP project cycle is through 2023.
Therefore, the City cannot make targets for the amount of public impervious surface area to be retrofitted by the
2030 or 2040 timeframes. The intention is that it will become the norm to identify and incorporate some form
of GSI in City projects to the extent feasible and as funding is available. Staff has made efforts, as described in
Section 5, to find sources of GSI funding. As a demonstration of the City’s commitment to its GSI Plan, the City
has completed the work described in the sections that follow.
19DRAFTGreen Stormwater Infrastructure Goals City of Dublin Green Stormwater Infrastructure Plan
3.2 Early Implementation, or “No Missed Opportunities”
Golden Gate Drive Streetscape Enhancement
Project . In 2010 the City, in a joint effort
with the Bay Area Rapid Transit District
(BART), was awarded a grant from the federal
Transportation for Livable Communities
program administered by the Metropolitan
Transportation Commission. The goal of the
grant and the project was to enhance pedestrian,
bicycle, and public transit connections in the
vicinity of the West Dublin BART station.
As part of that project, bulbouts were built
at intersections, including the addition of a
bioretention area at the northwest corner of
Golden Gate Drive at Saint Patrick Way. This
green street retrofit captures and treats 17,500
square feet of existing impervious surface area.
Pedestrian Improvements on Amador Valley Boulevard at Stagecoach Road and Wildwood Road . The Dublin
City Council approved a construction contract for this pedestrian safety improvement project on May 7, 2019.
Among the improvements being constructed will be a bioretention area in the new bulbout at the corner of
Wildwood Road and Amador Valley Boulevard. The bioretention area bulbout will treat 14,300 square feet of
existing roadway runoff on Wildwood Road. Construction is expected to be completed by August 2019.
3.3 Potential Project Cost Analysis
Potential project cost analysis, including construction and operations and maintenance (O&M). As part of the
project prioritization and mapping effort, the City completed a project cost analysis including design, construction,
and 20 years of O&M costs. The cost analysis was completed for the three project types described in Section 1.3 of
this plan: green street, parcel-based projects, and regional projects. The cost data that were applied to the projects
were compiled from GSI retrofit projects from 21 planned and 28 completed projects from Enhanced Watershed
Management Plans that have been constructed in Southern California; six projects from the Bay Area Stormwater
Management Agencies Association Clean Watersheds for a Clean Bay Project; and generalized cost per unit acre
data provided by the City of Union City. Table 4 provides design and construction costs per unit acre summary
statistics based on the completed analysis.
Table 4 | Design and Construction Cost Per Unit Acre Summary Statistic
Project Type Number
of Projects
Reviewed
Minimum
($/acre treated)
Median
($/acre treated)
Maximum
($/acre treated)
Mean
($/acre treated)
Green Street 8 $34,200 $134,000 $1,180,000 $283,000
Parcel-based project 17 $30,500 $134,000 $384,000 $167,000
Regional project 10 $12,000 $26,400 $64,200 $31,300
Bioretention area on Golden Gate Drive and St. Patrick Way
20 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Green Stormwater Infrastructure Goals
Annual O&M Costs are intended to account for activities necessary to maintain the effectiveness of a project that
recur on a regular basis, such as routine maintenance on an annual basis of repairs following a large storm event.
For the analysis conducted for this project, annual O&M costs do not include replacement or rehabilitation of the
GSI facilities. Replacement or rehabilitation is expected to occur approximately every 20 to 30 years. The average
O&M cost was calculated according to standard practice, as a percentage of design and construction cost. To
validate the standard practice O&M cost factor applied to projects provided in Table 5, O&M annual cost factors
were compared to values for projects completed in the City of Tacoma, Washington and the City of Portland,
Oregon. These cities have been tracking O&M costs for several years and therefore were able to provide ground-
truthing of the standard practice. The O&M dollars reported generally correspond to the standard annual cost
factors reported in Table 5 below.
Table 5 | O&M Annual Cost Factors for GSI Project Types
Green Stormwater Infrastructure
Project Type
O&M Annual Cost Factors
(Percent of Capital + Design Costs)
Green Street 3.6%
Parcel-Based Project 1.3%
Regional Stormwater Control 1.3%
For more information on the cost analysis methodology, refer to Appendix D.
3.4 Concept Plan Development
As part the project prioritization and mapping effort, five potential project locations were evaluated in the field for
feasibility. The five locations selected for evaluation included:
San Ramon Road between West Vomac and Alcosta Boulevard . This location is in the old urban land
classification and the street has high traffic volumes, providing the potential opportunity to capture and treat
higher pollutant loads. The project location was selected due to the possibility of managing higher pollutant loads
and because there is a landscape rehabilitation project in the City’s five-year CIP. A planning level concept plan
including four bioretention areas has been developed for this location. Building the bioretention areas as an add-
on to the landscape project would significantly increase the scope of the project, but would also provide water
quality improvements, stormwater flow control, and contribute to carbon sequestration. No funding has been
identified for design, construction, or operation and maintenance of this project. The project concept is provided
in Appendix E.
Iron Horse Trail at Amador Valley Boulevard . This location was selected even though the drainage area is new
urban/open space and therefore yields relatively low pollutant loads since the City has plans for a linear park
to be built adjacent to this location in the future. The site was evaluated to determine if a small, regional green
stormwater infrastructure project could be built at the same time as the linear park, saving construction costs
while providing stormwater flow control and carbon sequestration opportunities. A planning level concept plan
including a pretreatment swale and a bioretention area has been developed for this location. No funding has been
identified for design, construction, or operations and maintenance of this project. The project concept is provided
in Appendix E.
Village Parkway between Amador Valley Boulevard and Kimball Avenue . This location is in the old urban
land classification and the street has high traffic volumes, providing the potential opportunity to capture and
21DRAFTGreen Stormwater Infrastructure Goals City of Dublin Green Stormwater Infrastructure Plan
treat higher pollutant loads. Review of this location was superseded by the City’s efforts to develop a Downtown
Streetscape Master Plan since the team preparing the Downtown Streetscape Master Plan is identifying potential
locations that are amenable to adding GSI as part of that process.
Mape Memorial Park . This location was selected for evaluation as a potential collaborative GSI/flood control
project with Zone 7 Water Agency. The drainage for this area is from the old urban land classification. The project
was deemed infeasible since the park is topographically positioned in such a way that would preclude significant
stormwater runoff or inflow to be captured and stored.
Dublin Boulevard between Amador Plaza Road and Hansen Drive . This location is in the old urban land
classification and the street has high traffic volumes, providing the potential opportunity to capture and treat
higher pollutant loads. The location was deemed infeasible due to narrow sidewalks and medians, as well as a
natural gas transmission line that runs directly under the right-of-way.
3.5 Creation of Typical Stormwater Design Details
Starting with the San Francisco Public Utility Commission’s typical green infrastructure details, the City modified
select details to reflect requirements in MRP Provision C.3 and to address problematic GSI issues identified by
Dublin Staff (e.g. adding a pedestrian landing strip when GSI is located adjacent to parallel parking). The typical
stormwater details also incorporate inlet components from the City of Portland, Oregon. One of the details, GI-
XX, bioretention area with bike lane plan view, was modified from a charette conducted through the Bay Area
Stormwater Management Agencies Association Urban Greening Bay Area grant. In total, 12 typical GSI details
were developed. The typical details are provided in Appendix F.
3.6 Work with Private Developers
City Staff has been successful working with developers to get GSI construction in the public right-of-way as part
of development projects. During the entitlement process, Staff works with developers to identify locations where
it is feasible to install GSI and requests that the developer design and construct the GSI facilities. The request is
above and beyond what would be required based on Provision C.3.b requirements. For example, Staff worked with
the IKEA project team to include GSI on Arnold Road and Martinelli Way. Staff is crafting a formal process to
continue working with developers to include GSI in the public right-of-way and anticipates bringing the process
forward for City Council consideration in FY2019-20.
3.7 Municipal Regional NPDES Permit General Fund Reserve
In 2015, City Council approved a $2,250,000 MRP General Fund Reserve for development of a GSI Plan and
for installation of full trash capture devices. In the FY2018-19 budget, an additional $500,000 was added to the
MRP General Fund Reserve for GSI implementation efforts. In relation to GSI work, the funds have been used
for the design and construction of the bioretention area in the bulbout that is part of the pedestrian improvements
on Amador Valley Boulevard and Wildwood Road and to fund GSI Plan project work.
22 DRAFTCity of Dublin Green Stormwater Infrastructure Plan GSI Program Implementation
4. GSI PROGRAM IMPLEMENTATION
This section of the GSI Plan will discuss program implementation elements. Program implementation includes
on-going efforts to implement Provision C.3.b New and Redevelopment Standards, as well as new elements to
implement requirements in Provisions C.3.j. Green Infrastructure Planning and Implementation, C.11 Mercury
Controls, and C.12 Polychlorinated Biphenyls (PCBs) Controls. Program elements discussed will include:
1. Legal mechanisms for implementation
2. Summary of general guidelines and implementation checklists for GSI projects
3. Operations and maintenance, Inspection and Enforcement
4. GSI Requirements in Planning Documents
4.1 Legal Mechanisms for Implementation
As described in Section 1.2, the City of Dublin as a co-permittee of the MRP must require development projects
subject to Provision C.3.b to incorporate low impact development green stormwater infrastructure in project
designs. Chapter 7.74 of the City’s Municipal Code, Stormwater Management and Discharge Control, includes
mandates for best management practices for new and redevelopment projects consistent with the MRP. The City’s
Municipal Code establishes legal authority for the City to require Regulated Projects under Provision C.3.b to
comply with MRP requirements. Capital improvement projects that meet the impervious surface threshold limits
established in Provision C.3.b must also conform to the sizing and design requirements discussed in Section 4.2
below. Capital improvement projects that do not meet the impervious surface threshold limits established in
Provision C.3.b are under the control of the City and will be evaluated on a case-by-case basis to determine if
incorporation of GSI into the project design is feasible. The City intends to evaluate its implementation of this GSI
Plan and may consider whether additional policies could help facilitate GSI Plan implementation in the future.
4.2 General Guidelines and Implementation Checklists
A summary of general guidelines and implementation checklists for GSI projects is provided in Appendix G
to guide Staff in designing a project that has a unified, complete design that implements the range of functions
associated with GSI projects. To ensure GSI is appropriately incorporated into projects, Dublin Staff has created
processes and checklists to use during the design review process and at construction sign-off. City Staff are also
using checklists developed by the Alameda Countywide Clean Water Program (ACCWP) to assist with GSI
implementation efforts.
The summary of general guidelines includes:
• Hydraulic-sizing criteria
• Urban forestry considerations
• Bay Friendly Landscape principles
23DRAFTGSI Program Implementation City of Dublin Green Stormwater Infrastructure Plan
• How to coordinate GSI projects during construction.
Additional information on GSI project design may be found in the Alameda Countywide Clean Water Program
(ACCWP) C.3 Technical Guidance Manual.
The checklists developed to date for private development and capital improvement projects include:
• Stormwater management plan content
• Public Works Improvement Plan General Notes
• Stormwater Review Checklist
• Landscape Plan Checklist
• Inspector Final Inspection Checklist
• C.3. Operations and Maintenance Inspection Form
• Worksheet for Identifying Green Infrastructure Potential in Municipal Capital Improvement Program Projects
4.3 Operations and Maintenance, Inspection and Enforcement
As required by MRP Provision C.3, regular inspections occur for all GSI projects at least once every five years. These
inspections ensure that installed GSI facilities operate, in perpetuity, as designed. The inspections are completed on
both public and private properties and are managed by the City’s Environmental Services staff. Private developers
are required to enter into a Stormwater Management Maintenance Agreement which is recorded against the
property and runs with the land. City inspectors conduct inspections of GSI facilities at critical points during the
installation process to verify facilities are being constructed correctly. Prior to project acceptance, final inspections
of all GSI facilities are completed.
The transfer of maintenance responsibility for public projects is done at project close out, after the warranty
period. The City’s Public Works Department is responsible for the maintenance of public facilities. As discussed
in Section 5 below, the City of Dublin has no stormwater fee, therefore all maintenance activities are funded by
the General Fund.
The operations and maintenance enforcement program is managed by the Environmental Services Division. The
enforcement program adheres to the City’s Enforcement Response Plan.
4.4 GSI Requirements in Planning Documents
MRP Provision C.3.j requires that each municipality update relevant planning documents to include GSI. The
planning documents that are currently under development in the City of Dublin include the Downtown Dublin
Streetscape Master Plan and the update to the Parks and Recreation Master Plan, as described below. City Staff
intends to propose updates to Chapter 10, Community Design and Sustainability Element, and Chapter 12, Water
Resources Element, of the General Plan to include GSI guidance in FY2019-20 and it is anticipated that GSI will
be included in the Bicycle and Pedestrian Master Plan update which is also scheduled to begin in FY2019-20. As
other specific plans are updated in the future, green stormwater infrastructure will be included, as appropriate.
24 DRAFTCity of Dublin Green Stormwater Infrastructure Plan GSI Program Implementation
Downtown Dublin Streetscape Master Plan
The Downtown Dublin Streetscape Master Plan is in final draft form and includes GSI in the streetscape designs.
One of the specifically stated goals in this Master Plan is to “incorporate vegetated “green infrastructure” that
moderates micro-climate, creates habitat, and cleanses stormwater to protect the downstream water supply.” The
area included in this plan is included in Figure 5.
Figure 5 | Downtown Dublin Streetscape Master Plan Land Area
Update to the Parks and Recreation Master Plan
The City of Dublin is in the initial stages of an update to its Parks and Recreation Master Plan. The City’s
Environmental Services staff, which manages implementation of the GSI Plan, has participated in a stakeholder
meeting convened by the City’s Parks and Community Services Department. It is anticipated that GSI will be
included in the update to the Parks and Recreation Master Plan.
Retail District
Transit-oriented District
Village Parkway District
Limit of Work
Legend
25DRAFTEvaluation of Funding Options City of Dublin Green Stormwater Infrastructure Plan
5. EVALUATION OF FUNDING OPTIONS
GSI requirements are an unfunded mandate. However, to meet these unfunded provisions of the MRP, the
City of Dublin has examined multiple strategies as part of the consideration of potential funding and financing
mechanisms to implement prioritized GSI projects. Currently, City of Dublin does not have a general stormwater
fee and the MRP has not identified any funding sources for the new GSI regulations. As described in Section 3,
GSI and trash capture implementation is funded by the MRP General Fund Reserve. To implement the projects
identified through this GSI Plan, additional funding sources would need to be secured.
Research conducted to examine potential additional funding and financing sources thus far has included:
1. Examination of grants that may be applicable to the multi-benefits that stormwater facilities in Dublin can
provide;
2. Commissioning of an “Alternative Compliance Handbook”;
3. Discussions with Caltrans regarding their mitigation funds, and discussions with other potential public
partners;
4. Commissioning of a “Public-Private Partnership White Paper”;
5. Consideration of developer agreements or other ordinance that would require frontage improvements for
developments in specific regions in the city; and
6. Using Alameda County Measure D funds for Bay Friendly Landscaping.
Details regarding these identified potential implementation methods are provided in the following sections.
Documents referenced in this section are included in Appendix H.
Grants
Staff is interested in applying for grants to help implement GSI projects and has conducted an analysis to
characterize the specific multi-benefits that could be achieved through GSI projects to identify the grants best
matched to potential projects. The list of grants identified through this exercise, which Staff will be tracking, is
provided in Appendix H.
Alternative Compliance
The City may consider utilizing alternative compliance strategies to implement potential GSI projects identified
through this GSI Plan. The City commissioned the development of an “Alternative Compliance Handbook” in
2018, which provides an overview of the specific studies and administrative topics that could be considered in
developing an Alternative Compliance and/or In-Lieu Fee program. To facilitate public GSI construction, an
alternative compliance program could be developed such that developers could opt to provide in-lieu fees instead
of including on-site green stormwater infrastructure. The in-lieu fees could then be used to construct public GSI
projects. The Alternative Compliance Handbook is provided in Appendix H.
The City is also considering Water Quality Trading as a potential avenue for constructing feasible GSI projects.
The City has held discussions internally and with local partners regarding the potential for locally regional (i.e.,
Alameda Creek watershed) or larger regional (i.e., San Francisco Bay-draining communities) Water Quality
Trading plans.
26 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Evaluation of Funding Options
Public Partnerships
The City has explored the potential to team with local public partners on individual GSI projects that may be
mutually beneficial. For example, Public Works staff has had conversations with Caltrans regarding the potential to
implement GSI through Caltrans mitigation programs. In such a partnership, a GSI project could be constructed
in the City of Dublin to treat public stormwater runoff equivalent to the volume of runoff generated on adjacent
roadways required to be treated by Caltrans. The stormwater quality treatment pond constructed on the northwest
corner of San Ramon Road at Silvergate Drive is an example of a Caltrans mitigation program project constructed
in Dublin. That project completed construction in 2017.
Public-Private Partnerships
The City has investigated the potential to utilize Public-Private Partnerships (P3s) to implement GSI projects.
The City commissioned a White Paper titled “Public-Private-Partnerships (Performance-Based Infrastructure) for
Stormwater and MS4 Permit Compliance” to provide an overview of P3s, describe example P3s, and suggest
initial steps for developing a P3 program. Stormwater P3s are intended to help communities optimize limited
labor resources, meet compliance obligations, and control risk and finances to help build and maintain public
infrastructure. The White Paper provided in Appendix H provides more information on Public-Private Partnerships.
Development Agreements/Ordinance
As described in Section 3, the City has worked with developers during the entitlement process on specific projects
to have GSI installed in the public right-of-way and is currently working on a plan to formalize a process for
working with developers. The process may include a new or updated ordinance to require developers to provide a
specified and/or scalable amount of construction and maintenance (and/or funds for these activities) at locations
in which it is feasible to implement GSI.
Alameda County Waste Management Authority Measure D Funds
The City has identified “Measure D” funds (the Alameda County Waste Reduction and Recycling Act) as a source
of funding for portions of GSI project implementation. In particular, Measure D funds can be used for landscape
installations of at least 5,000 square feet (in some cases, 2,500 square feet) when the landscape goes through the
Bay-Friendly Landscape rating process. Measure D funds can also be used for maintenance of landscape areas
when Bay Friendly Landscape maintenance practices are being used. The City will consider the feasibility of
utilizing Bay-Friendly Landscape Practices for all GSI project installations to make use of these funds.
Other Mechanisms
Staff has reviewed other mechanisms of generating funds for GSI implementation, including but not limited to
fees, bonds, City MRP General Fund Reserve, and benefit assessment districts. Traditional forms of funding (e.g.,
General Fund) can be difficult to implement given competing interests for General Fund revenues. The City will
continue to consider these and other funding mechanisms as appropriate.
Next Steps for Funding and Financing Options Evaluation
In Fiscal Year 2019-20, staff will further evaluate a selection of GSI funding and financing options summarized in
this section. Specifically, it is anticipated that the potential for alternative compliance options and/or public private
partnership programs will be analyzed in more depth. Development of one or more of these programs would
utilize the steps outlined in the respective documents attached in Appendix H.
27DRAFTConclusion and Next Steps City of Dublin Green Stormwater Infrastructure Plan
6. CONCLUSION AND NEXT STEPS
Green stormwater infrastructure is a powerful tool that the City of Dublin is utilizing to create a healthier, more
sustainable urban future. Planning and investing in nature-based green stormwater infrastructure ensures the
City is moving toward achieving long-term goals to improve water quality, reduce flooding risks, mitigate climate
change impacts, improve the bicycle-pedestrian environment and mitigate the urban heat island effect. However,
dedicated funding sources are not available, and the City will need to identify ways to fund GSI projects.
Staff anticipates the next steps in the GSI implementation process will be to continue the work already in process
such as finishing a capital improvement project checklist and more fully exploring funding and financing options.
In addition, it is anticipated that Chapter 7.74 of the City’s Municipal Code, Stormwater Management and
Discharge Control, will be updated to provide further guidance and direction on GSI implementation. As described
in Section 4.5, City Staff anticipate proposing an update to Elements 10 and 12 of the General Plan as well as
the Bicycle-Pedestrian Master Plan in FY2019-20 to stress the importance of GSI as a stormwater strategy in the
City of Dublin moving forward. It is likely that the GSI Plan and the maps themselves will require revision in the
future as we learn more about how to effectively incorporate and maintain GSI in the City of Dublin. Through an
adaptive management process, Staff will periodically review this GSI Plan and make improvements, as necessary.
28 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix A
Appendix A
CITY OF DUBLIN GREEN INFRASTRUCTURE FRAMEWORK
29DRAFTAppendix A City of Dublin Green Stormwater Infrastructure Plan
30 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix A
31DRAFTAppendix A City of Dublin Green Stormwater Infrastructure Plan
32 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix A
33DRAFTAppendix A City of Dublin Green Stormwater Infrastructure Plan
34 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix A
35DRAFTAppendix A City of Dublin Green Stormwater Infrastructure Plan
36 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix B
Appendix B
MUNICIPAL REGIONAL STORMWATER NPDES PERMIT GREEN INFRASTRUCTURE PLAN REQUIREMENTS
This Green Infrastructure Plan has been developed to comply with Green Infrastructure Plan requirements in
Provision C.3.j of the MRP. Table B-1 links each section of this GSI Plan to the applicable MRP provision.
Table B-1 | Green Infrastructure Plan Requirements and Applicable MRP Provisions
GSI Plan Section Requirement Applicable MRP Provision
Section 1 Introduction C.3.j
Section 2 Prioritizing and Mapping Planned and Potential Projects C.3.j.i.(2)(a) – (c), and
C.3.j.i.(2)(j)
Section 2 Approach for Prioritizing and Mapping Projects C.3.j.i.(2)(a)
Section 2 Summary of Potential Projects C.3.j.i.(2)(b)
Section 2 Tracking and Mapping Completed Projects C.3.j.i.(2)(d), and C.3.d.iv.(1)
Section 3 Impervious Surface Retrofit Targets/GSI Goals C.3.j.i.(2)(c)
Section 3 Workplan for Completing Prioritized Projects C.3.j.i.(2)(j)
Section 3 Prioritized Projects for Alternative Compliance Program
or Early Implementation
C.3.j.i.(2)(j)
Section 4,
Appendix G
Summary of General Guidelines for GI Projects C.3.j.i.(2)(e),C.3.j.i.(2)(f),and
C.3.j.i.(2)(g)
Section 4 Relationship to Other Planning Documents C.3.j.i.(2)(h) and (i)
Section 4 Workplan to Incorporate GI Requirements in Planning
Documents
C.3.j.i.(2)(i)
Section 5 Evaluation of Funding Options C.3.j.i.(2)(k)
37DRAFTAppendix C City of Dublin Green Stormwater Infrastructure Plan
Appendix C
CITY OF DUBLIN GI PLAN FRAMEWORK ANALYSES METHODOLOGY MEMORANDUM
1111 Broadway, 6th Floor
Oakland, California 94607
PH 510.836.3034
FAX 510.836.3036
www.geosyntec.com
City of Dublin GI Plan Methodology Memorandum_FINAL_022817.docx
Memorandum
Date:28 February 2017
To:Shannan Young, City of Dublin
From:Lisa Austin,Principal; Kelly Havens,Project Engineer;and Austin Orr,
Senior Staff Engineer
Subject:City of Dublin GI Plan Framework Analyses Methodology
Memorandum
Geosyntec Project Number:WW2298
1.INTRODUCTION
The City of Dublin (City) is required by Municipal Regional Stormwater Permit (MRP)1
Provision C.3.j to develop a Green Infrastructure (GI) Plan for the inclusion of low impact
development drainage design on public and private lands, to be submitted with the 2019 Annual
Report.The GI Plan must include a mechanism to prioritize and map areas for potential and
planned projects consistent with the timeframes for assessing mercury and PCBs load reductions
specified in MRP Provisions C.11 and C.12 (i.e., 2020, 2030, and 2040).The GI Plan must also
identify targets for the amount of impervious surface to be retrofit over these timeframes to
reduce the adverse impacts of urbanization on water quality and include a work plan identifying
how the City will ensure that GI measures are included in future plans, among other
requirements. The City must prepare a framework (essentially a scoping document)that
describes the specific tasks and timeframes for development of the GI Plan. The GI Plan
framework must be approved by the City Council by June 30, 2017.
Geosyntec Consultants (Geosyntec) is assisting the City in conducting preliminary analyses to
support the tasks, timeframe, and potential cost implications that will be presented in the
framework. These preliminary analyses are intended to inform the level of implementation that
may be required as part of the GI Plan for consideration by the City when approving the
framework.The modeling and analyses which will occur as part of the development of the GI
Plan will refine these preliminary results.
1 Order No. R2-2015-0049.
38 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix C
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The methodology to conduct these analyses is described in this Analyses Methodology
Memorandum (Memo).This Memo outlines the methodology will be used to:
1.Calculate the City of Dublin’s Required Load Reductions for PCBs and Mercury per the
MRP for 2020, 2030, and 2040 (see Table 1);
2.Identify the load reductions already achieved and to be achieved through current,
planned, and future redevelopment projects;
3.Estimate the resulting public retrofit area needed to achieve the remaining load reduction
not achieved through current, planned, and future redevelopment projects;
4.Identify potential locations and treatment control measures for public retrofit projects;
and
5.Prioritize the identified potential public retrofit projects.
To conduct the analyses described herein, Geosyntec previously submitted a Data Needs Request
to the City (Attachment 1).Data were provided to Geosyntec on February 10, 2017.The data
that will be used for the project analyses described herein and the data sources are summarized in
Attachment 2.
The results of these analyses will provide information to be included in the GI Plan framework.
The analyses will be conducted in a manner such that they may be used to prepare the City’s GI
Plan with minor modifications and/or updates.
2.LOAD REDUCTIONS
2.1 TMDL Load Reductions
MRP Provisions C.11 and C.12 require the Permittees to implement programs to address the
mercury and PCBs total maximum daily load (TMDL)2 urban runoff waste load allocations
(WLAs).A summary of the Alameda County countywide total TMDL WLA as well as the
portion of the Alameda County countywide total WLA required to be addressed during the
current MRP term are summarized in Table 1. The portions of the countywide WLA for the
TMDL and current MRP term apportioned to the City using a population-based approach are
also provided in Table 1. These load reduction targets can be met by any acceptable combination
of control measures (i.e., not just GI).
2 San Francisco Bay and Guadalupe River Watershed Mercury TMDLs (Resolutions R2-2006-0052 and R2-2008-
0089) and the San Francisco Bay Region PCBs TMDL (Resolution R2-2008-0012).
39DRAFTAppendix C City of Dublin Green Stormwater Infrastructure Plan
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Table 1: PCBs and Mercury Load Reduction Performance Criteria for the City of Dublin
Requirement Date1
PCBS (kg/yr)Mercury (kg/yr)
Alameda County
Permittees2,3
City of
Dublin4
Alameda County
Permittees2,3
City of
Dublin4
TMDL WLA 2028 / 2030 4.45 0.089 19.0 0.380
MRP C.11/C.12 2020 0.94 0.019 See Note 3 See Note 3
Notes:
1.The mercury TMDL compliance date is 2028 and the PCBs TMDL compliance date is 2030.
2.The 2028/2030 load reduction performance criteria for Alameda County was calculated by subtracting the
applicable TMDL WLA from the baseline pollutant load (reported in the TMDL fact sheet)based on relative
population in the year 2000.
3.The 2020 PCBs load reduction was obtained from Table 12.1 of the MRP (page 114; note that 2018 criteria was
not included). The interim mercury requirement included in the MRP states “The TMDL implementation plan
calls for… attainment of an interim loading milestone by February 2018 of 120 kg/yr. The Permittees may
comply with any requirement of this provision through a collaborative effort.” This 120 kg/yr is not distributed
by County in the MRP.
4.The City of Dublin represented 2% of the Alameda County total population in the year 2000,according to
census data collected by the California Department of Finance.
2.2 Green Infrastructure Load Reductions
The MRP also includes specific PCBs and mercury load reduction performance criteria for GI
control measures by 2020 and 2040. A summary of the Alameda County countywide load
reduction performance criteria included in the MRP and the portion of the countywide load
reduction apportioned to the City using a population-based approach are provided in Table 2.
Table 2:PCBs and Mercury Load Reduction Performance Criteria for the City of Dublin
Requirement Date1
PCBS (kg/yr)Mercury (kg/yr)
Alameda County
Permittees1
City of
Dublin2
Alameda County
Permittees1
City of
Dublin2
MRP C.11/C.12 2020 0.037 0.001 0.015 0.0003
MRP C.11/C.12 2040 0.925 0.019 3.125 0.063
Notes:
1.The 2020 and 2040 load reduction performance criteria for GI implementation are stipulated in MRP C.11/C.12
(pgs. 110-111 for mercury, and 117-118 for PCBs).
2.The City of Dublin represented 2% of the Alameda County total population in the year 2000,according to
census data collected by the California Department of Finance.
3.CURRENT, PLANNED, AND FUTURE REDEVELOPMENT PROJECT LOAD
REDUCTIONS
The project will use accepted modeling tools to quantify expected load reductions achieved by
current, planned, and potential future private redevelopment projects (“C.3 projects”)
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implemented within the City.Current, planned,and future redevelopment projects will be
identified and mapped and load reductions will be calculated using the Interim Accounting
Methodology (BASMAA, 2016). Details regarding this methodology are included in the
following subsections. Geospatial data used for this analysis and subsequent analyses are listed
and described in Attachment 2.
3.1 Identification of Current, Planned, and Future Projects
The City will identify current, planned, and future C.3 redevelopment projects and will provide
the following information about each project to Geosyntec3:
1.Project Type (i.e., “parcel-based”, “green street/retrofit”, “full trash capture”)
2.Public/Private
3.Hydromodification Control
4.Project Name
5.Parcel/APN(s) developed, redeveloped,and/or treated
6.Description of project location
7.Construction Completion Date
8.Project Area (acres)
9.Treatment type (to be) implemented (or no treatment) and the percent of the project area
treated by each treatment type (0 –100%)
10.Hydraulic Sizing Criteria (i.e., MRP standard sizing, smaller, or larger)
11.Whether the project was included in the 2014 Integrated Monitoring Report
Geosyntec will review the City’s General Plan and may talk with staff from City departments
that may be aware of future development, such as the Transportation Department and the
Planning Department, if needed, in order to identify areas of future build-out that are not
included in this list of projects.
3 The Alameda Countywide Clean Water Program will be providing an Excel spreadsheet to be used to gather this
information.
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3.2 Mapping Development Projects
Following identification of current, planned, and future redevelopment projects to the extent
possible given the schedule, the identified projects will be mapped in GIS using the APN number
and the City of Dublin parcel land use layer. Project location will be checked using the location
description provided by the City. The projects will be classified based on the year project
construction was or is predicted to be completed (i.e., construction must be completed before the
end of the year for which the load reduction is calculated). Project classification will include
three categories:
1.Load reductions achieved by year 2020 (projects completed by June 30, 2020)
2.Load reductions achieved by year 2030
3.Load reductions achieved by year 2040
A map of the projects will identify the parcels developed, redeveloped,and/or treated, and
indicate the completion year categorization.The estimated load reduction associated with each
project will be provided in an accompanying table and will be calculated as described in the
following section.
3.3 Project Load Reduction Calculations
The Interim Accounting Methodology (BASMAA,2016)establishes the methodology to be used
by the Permittees to estimate load reductions during the current MRP permit term (2.0). The
Interim Accounting Methodology accounts for loads reduced from source property abatement
and other source control measures,as well as implementation of C.3 projects, redevelopment of
old industrial and old urban areas, and public retrofit projects.
To calculate the load reduction associated with each project, the identified projects will be
geospatially joined with the underlying “baseline” Yield Classification. The PCBs and mercury
baseline loads will be calculated for each project by multiplying the area redeveloped and/or
treated by the project by the yield associated with the underlying baseline Yield Classification.
For parcel-based C.3 projects, the post-project load will be calculated by multiplying the area
redeveloped and/or treated by the final Yield Classification (New Urban). For GI retrofit
projects,the post-project load will be calculated by applying a 70% reduction factor to the pre-
project load. The load reduction will be calculated as the difference between the post-project
load and the baseline load.
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The load reductions associated with each project will then be summed based on the project year
categorization to identify the total load reduction anticipated to be completed by current,
planned, and future projects for each of the target years (i.e., 2020, 2030, and 2040).
4.PUBLIC RETROFIT ANALYSIS
4.1 Load Reduction Assessment
The load reductions estimated to be achieved by current, planned, and future redevelopment
projects for each of the target years (i.e., 2020, 2030, and 2040) will be subtracted from the
required load reductions summarized in Table 1 above. The difference associated with the years
2020 and 2040 will represent the target load reductions for GI public retrofit projects for 2020
and 2040.For 2030, the additional load reduction needed could be achieved by GI retrofit
projects and/or other source control measures.
The calculated additional load reductions for 2020 and 2040 will be converted to total retrofit
treatment area to identify the acres of impervious area needed to be treated by public projects to
meet the load reduction targets. This will be conducted based on the Yield Classifications
throughout the City.The acres of each Yield Classification in the total area in the City not
associated with a current, planned, or future redevelopment projects will be identified
geospatially. Per the Interim Accounting Methodology, a GI project retrofit would result in a
70% reduction in the Yield Classification associated with the area treated. Starting with the Yield
Classifications with the highest yield (Old Industrial and Old Urban), the area required to
achieve the additional load reduction will be back-calculated assuming a 70% reduction in load
for all areas treated.A table of the required acres of each Yield Classification that must be
treated to achieve the additional load reduction for 2020 and 2040 will be developed.
For 2030, Geosyntec will work with the City to estimate potential load reductions associated
with any source control measures that could be implemented by the City,that reduction will be
subtracted from the additional load reduction, and the area required to treat the remaining
additional load reduction will be calculated similarly to the area calculation for 2020 and 2040.
4.2 Opportunity Analysis
Geosyntec will conduct an opportunity analysis to identify potential public retrofit projects to
treat the required impervious area identified as a result of the analysis conducted per the method
described above.Potential projects identified as part of the opportunity analysis will then be
prioritized via a prioritization analysis, described in the next section.
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The opportunity analysis will utilize GIS data to identify public parcels and/or rights-of-way
(ROW) where GI could feasibly be implemented based on technical screening criteria.
Opportunities for green streets and parcel-based regional GI facilities will be examined.This will
entail a desktop geospatial analysis conducted to identify where public parcels overlap with areas
that are physically and hydrologically conducive to GI implementation. The method proposed is
a tiered feasibility approach using the available GIS data summarized in Attachment 2. The
approach steps are summarized below:
1.Identify all publicly-owned parcels and ROWs not associated with current, planned, and
future redevelopment projects.Parcels will include those owned by all municipal
agencies, including those owned by the City, along with the fire department, school
district, water district, and other local agencies.
2.Screen identified parcels and ROWs for physical constraints which may restrict GI
implementation, including:
o Steep Slopes (estimated using publicly-available topographic data from USGS)
o 100-year FEMA floodplain boundary
o Environmentally sensitive areas within 300 feet of the parcel or ROW (i.e.,
designated wetlands, biologically sensitive areas, etc.)
3.Screen physically feasible regional facility locations for proximity to storm drain (i.e.,
must be within 500 feet)
4.Screen physically feasible locations with storm drain connections for hydrologic and
drainage area characteristics which could limit the efficacy of the GI, including:
o Very small drainage area
o Drainage area dominated by open space
If unavailable, drainage areas will be estimated based on available topographic
information and the storm drain network in the vicinity.
5.Identified BMP locations will be screened for infiltration feasibility, which will include
examining factors such as:
o Clay and low-infiltrating soil types
o Geotechnical hazards (e.g., landslide areas)
o Seasonal high groundwater elevations within 10 feet of the base of a GI facility
o Groundwater wells used for drinking water within 100 feet of the parcel
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o Locations of septic systems and drain fields within 100 feet of the parcel
o Known underlying soil or groundwater contamination within 100 feet of the
parcel (Contamination will be identified based on Geotracker sites; those adjacent
to a parcel or ROW will be eliminated)
Potential GI opportunities will be summarized in a table and on a map which will be discussed
with the City. Locations that are feasible for implementation of infiltration facilities, based on
underlying soil type and the restrictions listed above, will be classified. Information about each
identified GI opportunity will be provided, including the drainage area, summary of Yield
Classifications in the drainage area, and an estimate of the load reduction resulting from
implementation of treatment at the opportunity location. The potential load reduction will be
calculated using the Interim Accounting Methodology described in preceding sections and will
account for reductions from treatment only.
4.3 Prioritization Analysis
Following submittal of the GI Opportunities table and map to the City, Geosyntec will meet with
the City to establish a methodology to prioritize the identified locations. The prioritization
approach is anticipated to include, but may not be limited to ranking GI locations based on:
1.Overlap with areas slated for retrofit (e.g., planned transportation or street upgrade
projects)or proximity to planned redevelopment projects (e.g., roadways adjacent to
planned redevelopment);
2.Presence of higher-yield classifications in the drainage area (i.e., presence of Old
Industrial and higher proportions of Old Urban);
3.Total load reduction achieved by the GI project; and/or
4.Planning-level cost estimates.
Geosyntec will conduct a geospatial analysis to identify potential project locations which are co-
located with the relevant characteristics listed above and additional characteristics desired by the
City. A quantitative metric associated with the ranking characteristic (i.e., percent of location
overlapping with retrofit area or percent of drainage area classified as Old Urban)will be
calculated for each GI Opportunity and will be used to sort and rank the locations.
The ranked GI project locations will be presented to the City in a sorted table. The total load
reduction estimated for each project will be summed cumulatively to identify the projects which
might be implemented by 2020 and 2040 to achieve the load reduction performance criteria for
45DRAFTAppendix C City of Dublin Green Stormwater Infrastructure Plan
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GI in the MRP as well as the total load reduction that might be achievable by the 2028/2030
TMDL compliance date. The projects will be color coded by proposed implementation
timeframe and presented on a map along with other distinguishing information.
Final documentation for this project will include an initial screening level feasibility assessment
of the identified projects for the various timeframes.
5.POTENTIAL FUTURE CHANGES TO LOAD REDUCTION ACCOUNTING
MRP Provisions C.11.c and C.12.c require the Permittees to prepare a Reasonable Assurance
Analysis (RAA) for inclusion in the 2020 Annual Report that quantitatively demonstrates that
mercury load reductions of at least 10 kg/yr and PCBs load reductions of at least 3 kg/yr will be
achieved by 2040 through implementation of green infrastructure throughout the permit area.
This RAA will do the following:
1.Quantify the relationship between the areal extent of green infrastructure implementation
and mercury and PCBs load reductions. This quantification should take into consideration
the scale of contamination of the treated area as well as the pollutant removal
effectiveness of green infrastructure strategies likely to be implemented.
2.Estimate the amount and characteristics of land area that will be treated by green
infrastructure by 2020, 2030, and 2040.
3.Estimate the amount of mercury and PCBs load reductions that will result from green
infrastructure implementation by 2020, 2030, and 2040.
4.Quantitatively demonstrate that mercury load reductions of at least 10 kg/yr and PCBs
load reductions of at least 3 kg/yr will be realized by 2040 through implementation of
green infrastructure projects.
5.Ensure that the calculation methods, models, model inputs, and modeling assumptions
used have been validated through a peer review process.
The RAA for Alameda County may result in adjustments to the baseline assumptions in the
TMDLs, which may result in a change to the countywide and City load reduction requirements
for the 2028/2030 timeframe. As the RAA will not be conducted till after the City’s project is
complete, the load reductions presented in Table 1 above will be used for the project analyses.
When load reductions are recalculated as part of the RAA analyses, the project implementation
schedule identified as part of the prioritization analysis for this project may change, if load
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reductions required by 2028/2030 and 2040 decrease as a result of the RAA findings. The GIS
data and project information that is developed or compiled as part of this project will be designed
to be useful for developing the GI Plan and conducting the RAA, such that only the estimated
project load reductions may require future revision.
6.REFERENCES
BASMAA, 2016. Interim Accounting Methodology for TMDL Loads Reduced.Prepared by
Geosyntec Consultants and EOA, Inc. 19 September 2016.
*****
47DRAFTAppendix C City of Dublin Green Stormwater Infrastructure Plan
City of Dublin GI Plan Framework Analyses Methodology Memorandum
Attachment 1: Data Request
Data Request for City of Dublin
PLANNING DOCUMENTS:
•Future Development Planning Reports
•General Plans
•Specific Plans
•Any available geospatial data associated with figures and maps from the above
(geodatabases and shapefiles preferred)
CAD DETAILS (DWG):
•GI BMP standard detail file, to be edited to incorporate City of Dublin Standards
COST INFORMATION (PDF, EXCEL)FOR THE FOLLOWING:
•Completed GI Construction
•Planned GI Construction
If available, the following spatial datasets are requested from the City of Dublin
SPATIAL DATA LAYERS:
•From Online GIS Portal (url: https://gis.dublin.ca.gov/Html5Viewer/)
o Hazards Group (all)
o Operations and Maintenance Group (all)
o Planning Group
Development Projects
Land Use
Planning Areas
Specific Plan Areas
Zoning Districts
o Public Works
City Services
•Street Sweeping Zones
o Utilities
Storm Drain Network (all)
o Basemaps
Streets
Street Centerlines
Property
•Administrative Datasets
o Political boundaries (e.g. council districts, city and neighborhood boundaries)
o Building Footprints
o Road center and curb lines
o Rights-of-Way boundaries (polygons)
48 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix C
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Attachment 1: Data Request
•Elevation Datasets (one or more of the following, based on best available)
o LiDAR
o Digital Elevation Models (DEMs)
o Contours
•Land Use Datasets
o Parcels with relevant attributes including:
Zoning
Ownership
Whether the parcel pays taxes (to isolate publicly owned parcels)
o Impervious cover (w/ any attributes such as feature type)
o Land use/land cover
o Land use planning datasets (from Portal)
General Plans
Specific Plans
Zoning
•Environmental Datasets (GI siting and sizing)
o Streams/Rivers/Waterbodies
o Watersheds
o Locally-derived soil/geology/hydrogeology/geotechnical coverages
o County specific rain gauge locations
o Depth to groundwater
o Mapped contaminant plumes or contaminated sites
o Flood inundation or flood risk areas (FEMA flood zones in Portal)
o Rainfall isohyetal maps
•Stormwater/Water Quality Program Datasets
o Storm Drains Network (inlets, outfalls, open channels and gravity mains)
o Catchment/Sub-basin/Drainage Areas to Outfalls if available
o Trash priority areas
o Existing or Proposed (e.g. CIP) structural BMPs by type
Existing/Planned Flood control facilities
Include general BMP class and any photos, if available
o Areas that have been redeveloped since 2002 and have incorporated green
infrastructure (C.3)
Include APN, latitude/longitude, narrative description, if available
o Locations of drinking water treatment facilities (and locations of distribution lines
which convey water from source to treatment facility)
•High Resolution Aerial Imagery
FORMAT:
Digital Spatial Data Layers would ideally be provided as geo-referenced ArcGIS 10.x shapefiles,
geodatabases, or as raster image files (.img).We may be able to convert autocad datasets (.dwg)
into ArcGIS 10.x format if they are not available as shapefiles or geodatabases. Tabular datasets
cataloging specific features (e.g.,lists of existing structural BMPs) can be converted to viable
shapefiles if latitude and longitude is included. If Google Earth files (.kmz/ .kml) only are
available, we may be able to convert those into ArcGIS 10.x format.
49DRAFTAppendix C City of Dublin Green Stormwater Infrastructure Plan
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Attachment 2: Summary of Data to be Used
Table 1.City of Dublin GI Plan Framework Methodology Data Summary Table
Memo Section Goal Data Data Provider File Name or Feature Class Description
3. Identify
load
reductions
already
achieved
through
current,
planned, and
future
development
projects
Identify existing
and planned C.3
projects in the
City of Dublin
Project Information (in excel
database)
City of Dublin In process –Expecting from the
City March 8th
This dataset will
include all existing
C.3 project sites, all
C.3 sites currently
under construction,
and all future/planned
C.3 project sites that
are currently known.
Identify future
development
areas
Specific plan City of Dublin In process -anticipated from
City of Dublin
Additional future
redevelopment
projects that can be
included based on
specific plan or other
planning documents.
Development Projects
Completion Date
City of Dublin
City of Dublin
DBLN_Development_Projects
In process -anticipated from
Project Information deliverable
General Plan City of Dublin DBLN_General_Plan_LU
Streets City of Dublin ALCO_Centerlines_DBLN Used to identify
project boundaries if
APN not known.
Establish
baseline load for
identified
projects
Baseline land use yield
categorization
Geosyntec Landuse_Category.shp Bay Area yield
classifications grouped
by EOA as part of the
2014 IMR.
4.1-4.2
Conduct
analyses to
identify
potential
locations and
treatment
control
measures for
public retrofit
projects
Identify all
publicly owned
parcels and
ROWs not
associated with
current,
planned, and
future projects.
Assessor database (tax exempt
public agencies)
City of Dublin and County
Assessor
DBLN_Parcels Datasets used to
identify publicly
owned parcels or
ROWs which could be
retrofit.
Road ROWs City of Dublin In process -anticipated from
City of Dublin
City Owned Properties City of Dublin OM_Parcels
City of Dublin DBLN_Parcels
Alameda County 2014 geospatial.shp
Psomas PublicParcels
BMP Feasibility
and Infiltration
Feasibility
NRCS SSURGO data for City
of Dublin
National Resources
Conservation Service Web
Soil Survey1
soilmu_a_ca609 Datasets used to
identify publicly
owned parcels feasible
City of Dublin GI Plan Framework Analyses Methodology Memorandum
Attachment 2: Summary of Data to be Used
Table 1.City of Dublin GI Plan Framework Methodology Data Summary Table
Memo Section Goal Data Data Provider File Name or Feature Class Description
3. Identify
load
reductions
already
achieved
through
current,
planned, and
future
development
projects
Identify existing
and planned C.3
projects in the
City of Dublin
Project Information (in excel
database)
City of Dublin In process –Expecting from the
City March 8th
This dataset will
include all existing
C.3 project sites, all
C.3 sites currently
under construction,
and all future/planned
C.3 project sites that
are currently known.
Identify future
development
areas
Specific plan City of Dublin In process -anticipated from
City of Dublin
Additional future
redevelopment
projects that can be
included based on
specific plan or other
planning documents.
Development Projects
Completion Date
City of Dublin
City of Dublin
DBLN_Development_Projects
In process -anticipated from
Project Information deliverable
General Plan City of Dublin DBLN_General_Plan_LU
Streets City of Dublin ALCO_Centerlines_DBLN Used to identify
project boundaries if
APN not known.
Establish
baseline load for
identified
projects
Baseline land use yield
categorization
Geosyntec Landuse_Category.shp Bay Area yield
classifications grouped
by EOA as part of the
2014 IMR.
4.1-4.2
Conduct
analyses to
identify
potential
locations and
treatment
control
measures for
public retrofit
projects
Identify all
publicly owned
parcels and
ROWs not
associated with
current,
planned, and
future projects.
Assessor database (tax exempt
public agencies)
City of Dublin and County
Assessor
DBLN_Parcels Datasets used to
identify publicly
owned parcels or
ROWs which could be
retrofit.
Road ROWs City of Dublin In process -anticipated from
City of Dublin
City Owned Properties City of Dublin OM_Parcels
City of Dublin DBLN_Parcels
Alameda County 2014 geospatial.shp
Psomas PublicParcels
BMP Feasibility
and Infiltration
Feasibility
NRCS SSURGO data for City
of Dublin
National Resources
Conservation Service Web
Soil Survey1
soilmu_a_ca609 Datasets used to
identify publicly
owned parcels feasible
50 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix C
City of Dublin GI Plan Framework Analyses Methodology Memorandum
Attachment 2: Summary of Data to be Used
Memo Section Goal Data Data Provider File Name or Feature Class Description
Environmentally Sensitive
Areas
NOAA Office of
Response and Restoration2
NorthernCaliforniaESI.gdb for treatment retrofit
based on physical
characteristics, and
classify those feasible
for infiltration.
Groundwater Elevation Zone 7 Water Agency In process -potential to get this
data from Zone 7 Water Agency
Landslides and other
Geotechnical Hazards
California Department of
Conservation3
dub_lq, dub_ls
Topography -1/3 acre second
DEM raster data
USGS4 n38w123, n38w122
Floodplain City of Dublin FEMA_DFIRM_ZONE
Soil/groundwater contamination Geotracker5 Geotracker_db
Siting
Feasibility
Storm drain infrastructure City of Dublin DBLN_Storm_Drain_Mains These datasets help
identify sites to place
bmps.Drain inlet infrastructure City of Dublin DBLN_Storm_Drain_Structures
BMP drainage area City of Dublin/ Geosyntec Estimated by Geosyntec from
topography and storm drain
infrastructure
Trash Generation Areas City of Dublin/ Psomas TrashGenerationAreas
Trash Management Areas City of Dublin/ Psomas TrashManagementAreas
1.https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm
2.http://response.restoration.noaa.gov/maps-and-spatial-data/download-esi-maps-and-gis-data.html
3.http://maps.conservation.ca.gov/cgs/informationwarehouse/index.html?map=regulatorymaps
4.https://viewer.Nationalmap.gov/basic/
5.http://geotracker.waterboards.ca.gov/datadownload
City of Dublin GI Plan Framework Analyses Methodology Memorandum
Attachment 2: Summary of Data to be Used
Memo Section Goal Data Data Provider File Name or Feature Class Description
Environmentally Sensitive
Areas
NOAA Office of
Response and Restoration2
NorthernCaliforniaESI.gdb for treatment retrofit
based on physical
characteristics, and
classify those feasible
for infiltration.
Groundwater Elevation Zone 7 Water Agency In process -potential to get this
data from Zone 7 Water Agency
Landslides and other
Geotechnical Hazards
California Department of
Conservation3
dub_lq, dub_ls
Topography -1/3 acre second
DEM raster data
USGS4 n38w123, n38w122
Floodplain City of Dublin FEMA_DFIRM_ZONE
Soil/groundwater contamination Geotracker5 Geotracker_db
Siting
Feasibility
Storm drain infrastructure City of Dublin DBLN_Storm_Drain_Mains These datasets help
identify sites to place
bmps.Drain inlet infrastructure City of Dublin DBLN_Storm_Drain_Structures
BMP drainage area City of Dublin/ Geosyntec Estimated by Geosyntec from
topography and storm drain
infrastructure
Trash Generation Areas City of Dublin/ Psomas TrashGenerationAreas
Trash Management Areas City of Dublin/ Psomas TrashManagementAreas
1.https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm
2.http://response.restoration.noaa.gov/maps-and-spatial-data/download-esi-maps-and-gis-data.html
3.http://maps.conservation.ca.gov/cgs/informationwarehouse/index.html?map=regulatorymaps
4.https://viewer.Nationalmap.gov/basic/
5.http://geotracker.waterboards.ca.gov/datadownload
51DRAFTAppendix D City of Dublin Green Stormwater Infrastructure Plan
Appendix D
PROJECT COST ANALYSIS METHODOLOGY
City of Dublin Final Documentation_061517 20 06.07.2017
4. COST ANALYSIS METHODOLOGY (TASK 5 DOCUMENTATION)
4.1 Cost Analysis
This section summarizes the methodology used to estimate the capital costs and annual
operations and maintenance costs (O&M) for each of the potential projects identified in the
opportunity and prioritization analysis (summarized in Section 3 and provided in Appendix B,
i.e., external file [Opportunity Prioritization and Cost Analysis.xlsx])).
4.1.1 Cost Estimation Sources
The opportunity analysis identified five potential Project types, categorized based on the scale of
the project and the feasibility of infiltration. For the purposes of the cost analysis, this list was
reduced to three categories, as documented in Table 4-1.
Table 4-1: Cost Estimation Category
Potential Project Type Cost Estimation Category
ROW, Self-Treating without Infiltration Green Street
ROW, Self-Treating with Infiltration Feasible Green Street
Parcel, Regional Treatment without Infiltration Regional Stormwater Control
Parcel, Self-Treating without Infiltration Distributed Green Infrastructure
Parcel, Self-Treating with Infiltration Feasible Distributed Green Infrastructure
The cost data that were applied to the City retrofit projects were compiled from retrofit projects
from several sources:
28 completed projects and 21 planned projects from Enhanced Watershed Management
Plans (EWMPs) that have been constructed in Southern California;
Six projects from the BASMAA Clean Watersheds for a Clean Bay Project (CW4CB)
(BASMAA, 2017); and
Generalized cost per unit acre data provided by Union City.
These sources were processed to determine the capital costs (design and construction) and to
estimate recurring annual O&M costs in order to estimate project costs for the planned projects
in the City of Dublin. The inputs used to estimate O&M costs were also compared against
information from the City of Portland, Oregon, and the City of Tacoma, Washington (see Table
4-5).
52 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix D
City of Dublin Final Documentation_061517 21 06.07.2017
Information on facility type and project location were used to group the project data into green
street, distributed green infrastructure, and regional stormwater control categories. The following
facility types were included in each category:
Green Streets: Projects built within the right-of-way and include curb cutting and other
costs associated with street retrofits. These may include infiltration trenches, bioretention,
and infiltration galleries.
Distributed Green Infrastructure: Biofilters, swales, infiltration strips, and bioretention
installed in a parcel to treat runoff generated on that parcel.
Regional Stormwater Control: Infiltration basins, large storage facilities, and wetlands,
installed to treat runoff from a larger drainage area.
4.1.2 Design and Construction Unit Cost Estimates
Information for constructed EWMP projects was collected from various sources, including the
Proposition O monthly progress report from August 2016 (Bureau of Engineering Prop O Clean
Water Division, 2016) and publicly available online information such as the project fact sheets
provided by the City of Los Angeles stormwater program (http://www.lastormwater.org/).
EWMP cost data sources also include projects from the Santa Monica Bay Area (Beach Cities
EWMP Group, 2015; North Santa Monica Bay Coastal Watersheds EWMP Group, 2016; City of
Los Angeles, 2015), and Palos Verdes (Palos Verdes Watershed Management Group, 2015).
The cost information available in the reviewed EWMP references for constructed projects is
typically presented in the documentation as one final lump sum value, which may only include
construction or may include additional design and planning efforts. Some of the sources
reviewed provided unclear documentation of whether the presented costs corresponded to
“construction only” or “design and construction.” When utilizing these cost data, best
professional judgment was used to distribute the design and construction costs when the
information provided was unclear. If design costs were not available for a project, an estimate for
the design cost was inferred from other projects for which design costs were available. For
EWMP projects, the cost of design were calculated to be approximately 30% of the construction
cost. For projects with only construction costs, the design and construction cost was calculated as
1.3 x construction cost. If design and construction data was provided these values were not
adjusted. Some EWMP Projects summarized in these references were not included in this
analysis. This was the case if any of the following were true: a tributary drainage area could not
be determined; the project does not fall into one of the Potential Project Types; or project costs
could not be broken into components representing O&M, design, and construction.
53DRAFTAppendix D City of Dublin Green Stormwater Infrastructure Plan
City of Dublin Final Documentation_061517 22 06.07.2017
This cost analysis also includes cost data from six GI projects summarized in the BASMAA
CW4CB Project (BASMAA, 2017). For each of the projects used, both the cost of design and the
cost of construction were documented.
Additional local cost data were provided via e-mail communication from Union City (Union
City, 2017), which reported that their recent green streets projects had obtained a cost per unit
acre of treated area of approximately $300,000. Table 4-2 provides summary statistics for all
three of the cost data sources combined, and Appendix B provides the compiled cost data (see
the “Existing Project Costs Info” tab in the external file [Opportunity Prioritization and Cost
Analysis.xlsx]).
Table 4-2: Design and Construction Cost Per Unit Acre Summary Statistics
Project Type Number of
Projects (n)1
Minimum
($/ac)
Median
($/ac)
Maximum
($/ac)
Mean
($/ac)
Green Street 8 $34,200 $134,000 $1,180,000 $283,000
Distributed Green Infrastructure 17 $30,500 $134,000 $384,000 $167,000
Regional Stormwater Control 10 $12,000 $26,400 $64,200 $31,300
To apply the capital cost data to new projects, design and construction costs were compared to
the treated area for each project. Linear regression equations were developed using plots of
treated area versus design and construction cost using project data from the EWMP, CW4CB,
and Union City sources. Table 4-3 summarizes the cost formulas developed based on the linear
regression plots which predict design and construction cost based on treated area for each of the
three project categories.
Table 4-3: Cost Curves for Each Cost Category
Cost Estimation Category Design and Construction Cost Formula
Green Street $114,687 * acres + $36,927
Distributed Green Infrastructure $176,647 * acres + $12,935
Regional Stormwater Control $38,633 * acres
These formulas were applied to the estimated drainage areas for each identified project to
calculate an estimated capital cost for each project. The resulting costs per project are
summarized in Appendix B (see “Prioritization Table” tab of the external file [Opportunity
Prioritization and Cost Analysis.xlsx]).
54 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix D
City of Dublin Final Documentation_061517 23 06.07.2017
4.1.3 Annual O&M Cost Estimates
Annual O&M costs are intended to account for activities necessary to maintain the effectiveness
of a project that recur on a regular basis, such as routine maintenance on an annual basis or
repairs following a large storm event. For the analysis conducted for this project, annual O&M
costs do not include replacement (of portions) or rehabilitation of green infrastructure facilities,
which occurs approximately every 20 to 30 years. For the EWMP cost estimations, annual O&M
was assumed to be a percentage of the capital construction costs (i.e., design costs were not
accounted for in the percentage). Completed project costs for O&M were not available and were
estimated based on values for planned projects. In the Beach Cities EWMP (Beach Cities EWMP
Group, 2015), annual O&M costs were assumed to be 2% of the capital cost for distributed GI
and regional stormwater control facilities and 6% for green streets (USEPA, 2005; Weiss et al.,
2007). The activities included in these estimates are listed below.
O&M for distributed GI and regional facilities includes:
Landscape maintenance;
Media and gravel replacement when clogged and surface scarification is no longer
effective;
Pest control;
Sediment and pre-treatment cleanout;
Cleaning and removal of debris;
Repairs to inlet/control structures; and
Pre-treatment cleanup.
O&M for green streets includes:
Repairs to eroded areas;
Incremental landscape maintenance;
Media and gravel replacement when clogged and surface scarification is no longer
effective;
Removal of trash and debris; and
Removal of aged mulch with installation of a new layer.
The average O&M cost was then calculated as a percentage of design and construction cost. The
O&M annual cost factors are reduced when design is included in the implementation cost. As
55DRAFTAppendix D City of Dublin Green Stormwater Infrastructure Plan
City of Dublin Final Documentation_061517 24 06.07.2017
described in Section 4.1.2, project design was assumed to be 30% of construction costs for
EWMP projects when design costs were not provided. The average values for EWMP data were
used to calculate O&M cost factors based on combined construction and design costs (capital
costs, for the purpose of this analysis). This correction resulted in fixed rates of 3.6% of the
construction and design costs for green street projects and 1.3% of the construction and design
costs for distributed and regional projects, as summarized in Table 4-4. Annual O&M costs used
for this analysis are summarized for planned EWMP projects included in Appendix B (see the
“Existing Project Costs Info” tab in the external file [Opportunity Prioritization and Cost
Analysis.xlsx]).
Table 4-4: O&M Annual Cost Factors for Each Cost Category
Cost Estimation Category O&M Annual Cost Factors
(Percent of Capital + Design Costs)
Green Street 3.6%
Distributed Green Infrastructure 1.3%
Regional Stormwater Control 1.3%
To validate the O&M cost factor applied to the identified projects provided in Table 4-4, O&M
annual cost factors were compared to values for projects completed in the City of Tacoma,
Washington (J. Knickerbocker, personal communication, June 1, 2017) and the City of Portland,
Oregon (M. Juon, personal communication, May 30, 2017). The City of Portland quantified
O&M cost as a function of facility area as opposed to treated area. Local sizing guidance was
used to convert the cost per facility area to cost per treated area (City of Portland, 2016). The
annual O&M cost factors (as a percent of capital costs) calculated from planned EWMP projects
are comparable to the ranges experienced by both City of Tacoma and City of Portland projects.
56 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix D
City of Dublin Final Documentation_061517 25 06.07.2017
Table 4-5: Comparison of O&M Cost Estimates to Municipal Sources
Source BMP Type
Design and
Construction/Treated
Area ($/acre)
O&M
Cost/
Facility
Area
($/ft2)
O&M Cost/
Treated Area
($/acre)
O&M Annual
Cost Factor
(Percent of
Capital + Design
Costs) Low High Low High
City of Tacoma Bioretention $130,000 $400,000 $4,000 $6,000 1.0% - 4.6%
City of Portland Basin/
Regional1 $130,000 $400,000 $1.55 $6,077 1.5% - 4.7%
City of Portland Planter/Green
street1 $130,000 $400,000 $1.55 $4,051 1.0% - 3.1%
City of Tacoma Regional $4,000 $200 5.0%
EWMP Green St $283,000 $10,188 3.6%
EWMP Distributed GI $167,000 $2,171 1.3%
EWMP Regional $31,300 $407 1.3%
1 The design and construction costs for these practices were assumed to be the same as the Tacoma data for the
purposes of this comparison. Portland's 'basin' and 'planter' information is calculated as the $/sq ft * 43,560 *
Sizing Factor to obtain a $/treated acre. Sizing factors of 9% for basins and 6% for planters were used based on
the Portland Stormwater Management Manual (City of Portland, 2016).
2 The Design and Construction costs reported in this table are based on the mean values provided in Table 4-2
and O&M annual cost factors are as reported in Table 4-4.
4.1.4 Total Project Cost Estimation
The total cost of a planned project includes the capital costs and the annual costs over the design
life of the project.
Total Cost = Capital Cost + Annualized O&M Cost
The capital cost, which includes both the design cost and the construction cost, is estimated for a
new project based upon its cost estimation category and treatment area using the equations
provided in Table 4-3. The annual O&M cost is calculated by multiplying the capital cost by the
applicable fixed O&M cost factor from Table 4-4. For the purposes of this analysis, a 20-year
design life and a 3% inflation rate were used to calculate the total present value of the annualized
O&M costs.
Total project cost estimates are provided in Appendix B (see “Prioritization Table” tab of the
external file [Opportunity Prioritization and Cost Analysis.xlsx]) for each of the identified
opportunity areas identified in the City.
57DRAFTAppendix D City of Dublin Green Stormwater Infrastructure Plan
City of Dublin Final Documentation_061517 26 06.07.2017
5. REFERENCES
Alameda Countywide Clean Water Program (ACCWP), 2014. Integrated Monitoring Report Part
C: PCB and Mercury Load Reduction. Prepared for ACCWP by Geosyntec. March.
Bay Area Stormwater Management Agencies Association (BASMAA), 2016. Interim
Accounting Methodology for TMDL Loads Reduced. Prepared by Geosyntec Consultants
and EOA, Inc. 19 September.
BASMAA, 2017. Clean Watersheds for a Clean Bay (CW4CB) Final Report. May. Also
available at: http://basmaa.org/Clean-Watersheds-for-a-Clean-Bay-Project/About-the-
CW4CB-Project.
Beach Cities EWMP Group, 2015. Draft Enhanced Watershed Management Program (EWMP)
for the Beach Cities Watershed Management Area (Santa Monica Bay and Dominguez
Channel Watersheds). June.
Bureau of Engineering Prop O Clean Water Division, 2016. Proposition O – Clean Water Bond
Program August 2016 Monthly Report. August. http://www.lacitypropo.org/
City of Los Angeles, Los Angeles County Flood Control District, County of Los Angeles, City
of Santa Monica, and City of El Segundo, 2015. Draft Santa Monica Bay Jurisdictional
Group 2 and 3 Enhanced Watershed Management Program. June.
City of Portland, Stormwater Management Manual, 2016.
https://www.portlandoregon.gov/bes/64040
Geosyntec, 2017. City of Dublin GI Plan Framework Analyses Methodology Memorandum.
Prepared by Geosyntec. 28 February.
North Santa Monica Bay Coastal Watersheds EWMP Group, 2016. Enhanced Watershed
Management Program (EWMP) for North Santa Monica Bay Coastal Watersheds. March.
Palos Verdes Watershed Management Group, 2015. Draft Enhanced Watershed Management
Program (EWMP) for the Palos Verdes Watershed Management Group.
Union City, 2017. E-mail communication from Thomas Ruark to Shannan Young. 19 April
2017.
United States Environmental Protection Agency (USEPA), 2005. National Management
Measures to Control Nonpoint Source Pollution from Urban Areas. EPA-841-B-05-004,
U.S. Environmental Protection Agency, Washington, D.C.
58 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix D
City of Dublin Final Documentation_061517 27 06.07.2017
Weiss, P.T., J.S. Gulliver, and A.J. Erickson, 2007. Cost and Pollutant Removal of Storm-Water
Treatment Practices. Journal of Water Resources Planning and Management, Vol. 133.
59DRAFTAppendix E City of Dublin Green Stormwater Infrastructure Plan
Appendix E
POTENTIAL PROJECT CONCEPT PLANS
SAN RAMON ROAD: ALCOSTA BOULEVARD TO WEST VOMAC
ROAD BIORETENTION RETROFIT PROJECT
PROJECT CONCEPT
Portions of San Ramon Road were identified as high-priority project opportunities in the green
infrastructure retrofit opportunity analysis conducted in April 2017. This project concept focuses
on the San Ramon Road retrofit opportunity segment between Alcosta Boulevard and West Vomac
Road. The project is not located in a high-trash area, according to on-land visual trash assessments
performed by EOA, Inc.
The project would entail installation of four bioretention cells (SR01, SR02, SR03, and SR04) with
underdrains along landscaped strips adjacent to the roadway. These facilities would provide
treatment of runoff from portions of San Ramon Road.The location and drainage areas of these
facilities are shown on Figure SR-1,and a more detailed view is shown on Figure SR-2.
This portion of San Ramon Road is colinear with the historical Sta te Highway 21, and some
remnants of the original highway slab may still exist below grade. These slabs may require removal
prior to construction of some or all of the bioretention facilities.A summary of the four proposed
bioretention facilities is provided:
•Bioretention facility SR01 -located near the southwest corner of the intersection between San
Ramon Road and West Vomac Road, in the landscaped strip between San Ramon Road and
the bike path. Approximately 70 feet of new storm drain pipe would be required to connect the
facility to the existing storm drain system. No trees would need to be relocated to install this
facility. A fence is recommended on the western portion of the facility to protect cyclists in the
bike lane.
•Bioretention facility SR02 -located near the southeast corner of the intersection between San
Ramon Road and West Vomac Road,in the landscaped strip between the pedestrian walkway
and the adjacent residential properties.Outflow from the facility would discharge directly to
an existing culvert. One tree would need to be relocated to install this facility. A large gas
transmission pipeline which runs along San Ramon Road is located in the vicinity of the
facility. As sited in the attached figures, the facility is set back 10 feet horizontally from the
pipeline; if this is not sufficient, implementation may not be feasible.The pipeline location is
based on San Ramon Road as-built plans. The precise location and depth will need to be
verified prior to construction.
•Bioretention facility SR03 -located on the western portion of San Ramon in the landscaped
strip between the road and bike path.A fence is recommended on the western portion of the
facility to protect cyclists in the bike lane. One tree would need to be relocated to install this
facility. The facility is located adjacent to an existing storm drain and no additional pipe would
be expected to be needed to connect the facility to the storm drain.
•Bioretention facility SR04 -located on the eastern portion of San Ramon Road in the
landscaped strip between the pedestrian walkway and the adjacent residential properties. One
60 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix E
tree would need to be relocated to install this facility. The facility is located adjacent to an
existing storm drain and no additional pipe would be expected to be needed to connect the
facility to the storm drain.
The bioretention facilities have been sized at approximately 2% of impervious tributary area,
consistent with continuous modeling results for 80% capture for bioretention with a 6-inch
reservoir.Facility areas could be increased to provide additional hydromodification and trash
capture benefits, but the density of landscaping in the area would likely necessitate additional tree
relocation to accommodate larger facilities.
DESIGN INFORMATION
Drainage Catchment Imperviousness:95%
Land Use Yield Category (%):100% Old Urban
Facility Type:Bioretention with underdrains
Location Total Drainage Area (sq-ft)Bioretention Footprint (sq-ft)
SR01 17,400 340
SR02 23,000 450
SR03 24,300 470
SR04 30,100 580
PROJECT BENEFITS
PCBs Loads Reduced:TBD
Mercury Loads Reduced:TBD
Trash Loads Reduced:N/A, low trash generating area.
Water Supply Benefits:None anticipated.
Flood Management Benefits:The project would provide some flood management benefits through
peak flow attenuation.
Natural Drainage System Benefits:None anticipated.
Habitat or Open Space Benefits:None anticipated.
Community Benefits:The project would provide an opportunity for educational signage
regarding stormwater, green infrastructure, and creek health.
61DRAFTAppendix E City of Dublin Green Stormwater Infrastructure PlanCOSTESTIMATEItemQuantityUnitUnit Price1Cost1ReferenceExcavation240CY$ 27.56 $ 6,615.29 Adjusted Caltrans 2015 Unit Bid PricesClearing & Grubbing1840SF$ 0.16 $ 288.76 2017 BNI Facilities Manager's Costbook 02230.10Soil Disposal240CY$ 31.39 $ 7,532.78 Engineering Judgement2Site Grading205SY$ 34.26 $ 7,024.20 Adjusted 2001 Caltrans BMP Retrofit PilotErosion control blankets1840SF$ 0.58 $ 1,058.77 Engineering Judgement2Class 2 Permeable Rock70CY$ 53.24 $ 3,726.58 Adjusted Caltrans 2015 Unit Bid Prices 682042Bio-TreatmentSoil Mix100CY$ 88.67 $ 8,867.24 Adjusted 2017 Lyngso Garden Biotreatment Soil MixPlace Bio-Treatment Soil Mix205SY$ 3.75 $ 767.82 2017 BNI Facility Manager's Costbook 02910.10Mulch1840SF$ 0.52 $ 962.52 2017 BNI Facility Manager's Costbook 02910.10Shrub Material and Installation368EA$ 52.31 $ 19,250.45 2017 BNI Facility Manager's Costbook 02910.30Replacement Tree Material and Installation Cost3EA$ 428.95 $ 1,286.85 2017 BNI Facility Manager's Costbook 0293.604" Perforated PVC Pipe160LF$ 20.92 $ 3,347.90 2017 BNI Facility Manager's Costbook, 02630.704" PVC Cleanout w/ Cap10LF$ 20.92 $ 209.24 2017 BNI Facility Manager's Costbook, 02630.70Overflow Riser w/ Grate4EA$ 8,369.76 $ 33,479.04 Adjusted 2017 Oldcastle Precast 12x12 SwaleguardPVC Pipe to Storm Drain80LF$ 10.46 $ 836.98 2017 BNI Facility Manager's Costbook, 02630.70Connection to Existing Storm Drain4EA$ 2,092.44 $ 8,369.76 Engineering Judgement2Irrigation system1840SF$ 0.72 $ 1,327.11 2017 BNI Facility Manager's Costbook, 02810.40Curb cut inlet4EA$ 1,046.22 $ 4,184.88 Engineering Judgement2Remove and replace irrigation lines1840SF$ 1.31 $ 2,412.52 Engineering Judgement2Remove Existing Highway Slab as Needed1840SF$ 8.08 $ 14,874.42 Adjusted Caltrans 1995 Unit Bid PricesConstruction Cost Subtotal$ 126,423.12Mobilization/Demobilization10%$ 12,642.31 Estimated as a percentage of Construction Cost SubtotalSubtotal 1$ 139,065.43 Engineering Overhead20%$ 27,813.09 Estimated cost as a percentage of Subtotal 1Subtotal 2$ 166,878.52 Contingency30%$ 50,063.56 Estimated cost as a percentage of Subtotal 2Subtotal 3$ 216,942.07 TOTAL COST ESTIMATE$ 217,0001All costs are in 2018 dollars. Inflation rate calculated from U.S. Department of Labor, Bureau of Labor Statistics. 2Cost basis developed as part of Geosyntec work on 2017 Caltrans District 4 Phase I Plan for TMDL Implementation, reviewed by Caltrans. Cost adjusted for inflation.
62 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix E
REFERENCES
BNi® Building News, 2017.Facilities Manager's Costbook. BNI Publications, Inc.
California Department of Transportation (Caltrans),1995.1995 Contract Cost Data. Retrieved
from: http://sv08data.dot.ca.gov/contractcost/
Caltrans, 2001. Caltrans BMP Retrofit Pilot Program. May. Retrieved from Construction Cost
Data Summary: Districts 7 and 11:
http://www.dot.ca.gov/hq/env/stormwater/special/newsetup/_pdfs/new_technology/CTS
W-RT-01-050/AppendixC/CostRpt05-01.pdf
Caltrans, 2015. 2015 Contract Cost Data. Retrieved from:
http://sv08data.dot.ca.gov/contractcost/
EOA, Inc, 2018. Trash Control Status of Land Areas >10,00ft2 Draining Directly to the MS4.
Lyngso Garden, 2018. Biotreatment soil mix. Retrieved from:
https://store.lyngsogarden.com/products/biotreatment-soil-mix-509.html
Oldcastle Infrastructure, 2018. Swalegard® Bioretention Overflow Filter. Retrieved from:
https://oldcastleprecast.com/oldcastle_product/12x12-swalegard-overflow-filter/101180/
63DRAFTAppendix E City of Dublin Green Stormwater Infrastructure Plan
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64 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix E
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SR04SR02SR03SR01P:\GIS\City of Dublin\Projects\Concept Plans\San Ramon Detail.mxd 9/7/2018 9:33:55 AM LegendExisting Storm Drain Infrastructure"SCatch Basin / Inlet!.Manhole / Junction BoxCreek / Open ChannelCulvertSurface Flow Direction< 12" RCP12 - < 18" RCP18 - < 33" RCP>= 33" RCPExisting Gas PipelineProposed Control MeasuresBioretention with UnderdrainNew storm drain pipeProposed Drainage AreasSR01SR02SR03SR040110Feet³City of Dublin GI Plan / SWRPSan Ramon Road - Alcosta to W VomacDetail MapOaklandSeptember 2018FigureSR-2BellinaSt
65DRAFTAppendix E City of Dublin Green Stormwater Infrastructure Plan
IRON HORSE TRAIL AT ALAMO CREEK AND SOUTH SAN RAMON CR EEK
REGIONAL BIORETENTION PROJECT
Note: this project is on hold until the Master Plan has been completed.
PROJECT CONCEPT
There is an existing Iron Horse Nature Park and Open Space Master Plan for the former Union
Pacific railroad right-of-way. This area is adjacent to the Iron Horse Trail near the confluence of
Alamo Creek and South San Ramon Creek, and has been acquired by the City of Dublin. The
Master Plan sites aesthetic and recreation features, including community gardens, a children’s
natural play area, and flexible open space. The proposed concept would incorporate a bioretention
area and pretreatment swale into the Master Plan area to treat surface runoff from adjacent
residential areas. A map with the proposed drainage areas and treatment facility location, identified
as IH-01 and, is provided as Figure IHT-1, with a more detailed view provided as Figure IHT-2.
Drainage area delineation and facility siting/sizing was based on a preliminary field visit and
review of publicly-available aerial imagery, LIDAR elevation data, and City of Dublin storm drain
maps. Plan review and field confirmation of drainage area is recommended in future phases of this
project.
IH-01 consists of a bioretention area with an underdrain as well as a vegetated swale used for
pretreatment. The bioretention area is located in an existing vegetated area at the northwest end of
the Iron Horse Trail near the intersection with Amador Valley Blvd. The pretreatment swale is
located along an existing vegetated depression/channel, from the proposed bioretention location
nearly to Alamo Creek.
The drainage area tributary to the IH-01 facility is approximately 11.5 acres, consisting of 8.8 acres
of residential areas and 2.7 acres of open space. The residential areas consist of portions of the
Alamo Creek Villas and Heritage Commons developments adjacent to the Iron Horse Trail.
Currently these portions of residential area discharge to Alamo Creek through a 24-inch storm
drain pipe; approximately 100 feet of proposed new storm drain pipe would direct this runoff into
the proposed pretreatment swale and then into the proposed bioretention facility. Additional sheet
flow runoff from adjacent open space would also flow into the proposed facilities. Outflow from
the facility would discharge into South San Ramon Creek through a retrofit of an existing inlet and
storm drain pipe. The existing 150 feet of 15-inch storm drain may need to be upsized.
The bioretention facility is currently sized at approximately 2% of impervious tributary area,
consistent with continuous modeling results for 80% capture for bioretention with a 6-inch
reservoir. The proposed layout is flexible, however, and the bioretention area could easily be
redesigned to be larger or smaller depending on refinement of the drainage area characterization.
The pretreatment swale is sized per the Alameda C.3. technical guidance 0.2 inch-per-hour
intensity method (sized for the water quality design flow resulting from rain event with
66 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix E
precipitation intensity of 0.2 inches per hour), with a 10-foot bottom width and 225-foot length, to
achieve a residence time of 8 minutes.
A second treatment facility was considered in the triangular open area east of South San Ramon
Creek, but was found to be infeasible due to the location of the existing pipeline.
Design Information
Facility
Total
Drainage
Area (ac)
Imperviousness
(Approximate)
Impervious
Drainage Area
(ac)
Facility
Footprint
(sq-ft)
Land Use
IH-01 Bioretention 11.5 65% 7.5 6,700 77% New Urban
23% Open Space IH-01 Swale 6,000
Cost Estimate
More detailed planning level costs will be developed.
67DRAFTAppendix E City of Dublin Green Stormwater Infrastructure Plan"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S#0#0"S"S"S"S"S"S!."S"S"S"S"S"S"S"S"S#0"S!.!."S"S!."S"S"S"S"S!."S"S"S!."S"S"S"S"S"S"S#0!.!."S"S"S"S"S"S#0"S!."S"S"S"S"S"S"S!.!."S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S"S!.!.#0#0"S"S"S"S"S"S"S"S"S"S"S#0!.#0"S#0#0"S#0#0"S"S"S"S!.!."S!.!.!.!.!."S"S"S"S"S"S"S"S"S"S"S!."S"S"S"S"S!."S"S"S!.!.!.!."S"S"S"S"S#0!.!H!H!H!H!H"S"S"SIH-01P:\GIS\City of Dublin\Projects\Concept Plans\Iron Horse Trail Drainage.mxd 9/7/2018 9:40:05 AM LegendExisting Storm Drain Infrastructure"SCatch Basin / Inlet!.Manhole / Junction Box#0Outfall / HeadwallCreek / Open ChannelCulvertSurface Flow Direction< 12" RCP12 - < 18" RCP18 - < 33" RCP>= 33" RCPExisting UtilitiesPipeline!HUtility PoleProposed Drainage AreasIH-01Proposed Control MeasuresBioretention with UnderdrainPretreatment SwaleNew Storm Drain Pipe0130Feet³City of Dublin GI Plan / SWRPIron Horse Trail Bioretention ConceptDrainage MapOaklandSeptember 2018FigureProject Location³IHT-1
68 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix E"S"S"S#0#0"S"S"S"S"S"S!."S"S"S"S"S"S"S"S#0!."S"S"S"S"S"S"S"S"S"S"S"S#0"S!."S"S"S"S"S"S"S"S"S"S"S"S"S"S!.!.#0#0"S"S"S"S"S"S"S"S#0#0"S!.!."S!.!.!.!.!."S"S"S"S"S"S"S"S!.!.!.!H!H!H!H!H"S"S"SIH-01P:\GIS\City of Dublin\Projects\Concept Plans\Iron Horse Trail Detail_IH01_only.mxd 9/7/2018 9:40:06 AM LegendExisting Storm Drain Infrastructure"SCatch Basin / Inlet!.Manhole / Junction Box#0Outfall / HeadwallCreek / Open ChannelCulvertSurface Flow Direction< 12" RCP12 - < 18" RCP18 - < 33" RCP>= 33" RCPExisting UtilitiesPipeline!HUtility PoleProposed Drainage AreasIH-01Proposed Control MeasuresBioretention with UnderdrainPretreatment SwaleNew Storm Drain Pipe075Feet³Iron Horse Trail Bioretention Concept Detail MapCity of Dublin GI Plan / SWRPOaklandSeptember 2018FigureIHT-2
69DRAFTAppendix F City of Dublin Green Stormwater Infrastructure Plan
Appendix F
CITY OF DUBLIN TYPICAL STORMWATER DETAILS
Standard specifications and typical design drawings for GSI projects are provided on the following pages, as
indicated in Table F-1.
Table F-1 | CITY OF DUBLIN TYPICAL STORMWATER DETAILS
Sheet No .Title of Drawing/Standard Specifications Notes
GI-1 Bioretention Area Notes Applies to all details
GI-2A Bioretention area: Plan view with street parking Parking lane
GI-2B Bioretention area: Bulbout plan view Intersection with sidewalks
GI-2C Bioretention area street median —
GI-XX Bioretention area with bike lane plan view Bike lane
GI-3A Bioretention Area: Sloped Sides Cross Section Sidewalk
GI-3B Bioretention Area: Vertical Side Wall Cross Section Parking lane and sidewalk
GI-4 Bioretention Components: Outlet Detail —
GI-5 Bioretention Components: Edge Treatment Detail No parking
GI-6A Bioretention Components: Gutter Curb Cut Inlet Detail —
GI-6B Bioretention Components: Trench Drain Curb Cut Inlet Detail Parking lane and sidewalk
GI-6C Bioretention Components: Curb Cut At Bulbout Inlet Detail Intersection with Sidewalks
GI-7 Bioretention Components: Check Dam Detail Slope requiring check dams
70 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix FNOTES & GUIDELINES:1.THE ENGINEER SHALL ADAPT PLAN AND SECTION DRAWINGS TO ADDRESS SITE-SPECIFIC CONDITIONS.2.BIORETENTION AREA SHALL BE SIZED TO MEET THE REQUIREMENTS OF MRP PROVISION C.3 SIZING.3.48 HOUR MAXIMUM FACILITY DRAWDOWN TIME (TIME FOR MAXIMUM SURFACE PONDING TO DRAIN THROUGH THEBIOTREATMENT SOIL AFTER THE END OF A STORM). REFER TO C.3 TECHNICAL GUIDANCE MANUAL (ACCWP) FORDRAINAGE CONSIDERATIONS.4.A STORAGE LAYER OF CALTRANS STANDARD CLASS II PERMEABLE MATERIAL IS REQUIRED UNDER THEBIOTREATMENT SOIL. REFER TO C.3 TECHNICAL GUIDANCE MANUAL (ACCWP) FOR SPECIFICATIONS.5.THE BIORETENTION AREA SLOPE IS TYPICALLY DESIGNED TO MATCH THE LONGITUDINAL SLOPE OF THE ADJACENTROADWAY/SIDEWALK. THE BOTTOM OF THE BIORETENTION AREA, HOWEVER, SHOULD BE FLAT. CHECK DAMS SHALLBE USED TO TERRACE FACILITIES TO PROVIDE SUFFICIENT PONDING FOR SLOPED INSTALLATIONS. ENGINEERSHALL SPECIFY CHECK DAM HEIGHT AND SPACING. REFER TO DETAIL GI-7 FOR GUIDANCE ON CHECK DAM DESIGN.6.DEPENDING ON THE DEPTH OF THE BIORETENTION AREA, ADDITIONAL STRUCTURAL CONSIDERATIONS MAY BEREQUIRED TO ADDRESS HORIZONTAL LOADING. REFER TO DETAIL GI-5 FOR GUIDANCE ON EDGE TREATMENTS.7.WHEN FACILITY CONSTRUCTION IMPACTS EXISTING SIDEWALK, ALL SAW CUTS SHALL ADHERE TO CITY OF DUBLINSTANDARDS. SAW CUTS SHALL BE ALONG SCORE LINES OR ALONG CONSTRUCTION JOINTS, AS DETERMINED BYTHE CITY ENGINEER, AND ANY DISTURBED SIDEWALK FLAGS SHALL BE REPLACED IN THEIR ENTIRETY.8.BIORETENTION AREAS IN PUBLIC RIGHT OF WAY SHALL BE DESIGNED WITH AN EMERGENCY OVERFLOW. IN THEEVENT THE BIORETENTION AREA OVERFLOW DRAIN IS OBSTRUCTED OR CLOGGED, THE INUNDATION AREA SHALLBE CONTAINED WITHIN THE STREET AND SHALL NOT BE WITHIN ADJACENT PRIVATE PROPERTIES.9.BIORETENTION AREA VEGETATION SHALL BE SPECIFIED BY LANDSCAPE DESIGN PROFESSIONAL. SEE C.3TECHNICAL GUIDANCE MANUAL (ACCWP) FOR PLANT LIST AND VEGETATION GUIDANCE.10.THE ENGINEER SHALL EVALUATE THE NEED FOR EROSION PROTECTION AT ALL INLET LOCATIONS. ALL COBBLESUSED FOR ENERGY DISSIPATION SHALL BE GROUTED.11.THE PROJECT PLANS SHALL SHOW ALL EXISTING UTILITIES AND INDICATE POTENTIAL UTILITY CROSSINGS ORCONFLICTS.12.NO UTILITIES, NEW OR EXISTING, SHALL BE LOCATED WITHIN OR BELOW THE BIORETENTION AREA.13.MINIMUM UTILITY SETBACKS AND PROTECTION MEASURES SHALL CONFORM TO CURRENT CITY OF DUBLINSTANDARDS AND OTHER UTILITY PROVIDER REQUIREMENTS.14.VERTICAL SIDEWALLS EXTENDING INTO EXISTING STORM DRAIN PIPE TRENCH BACKFILL SHALL BE DESIGNED WITHA CONCRETE BACKFILL ACCEPTABLE TO THE CITY ENGINEER.15.OVERFLOW RISER MUST BE FORMED SUCH THAT IT IS A MINIMUM OF 6" ABOVE THE BOTTOM OF THE SYSTEM INLET,OR AS DESIGNED. PLACE STRUCTURE ADJACENT TO PEDESTRIAN EDGE TO ALLOW FOR MONITORING ACCESS.16.DETAILS WERE ADAPTED FROM SFPUC GREEN INFRASTRUCTURE TYPICAL DETAILS AND SPECIFICATIONS.17.DETAILS WERE DEVELOPED BY GEOSYNTEC CONSULTANTS.RELATED TECHNICAL GUIDANCESOURCEBIORETENTION: - BIOTREATMENT SOIL MIX - CALTRANS CLASS II PERM LAYER STORAGE - PERFORATED UNDERDRAIN - NON-FLOATING MULCHC.3 TECHNICALGUIDANCE MANUAL(ACCWP)PURPOSE:PROVISION C.3 OF THE MUNICIPAL REGIONAL STORMWATER NPDES PERMIT (MRP) REQUIRES TREATMENT OF IMPERVIOUS SURFACES USING GREEN INFRASTRUCTURE FOR BOTH PUBLIC AND PRIVATEDEVELOPMENT PROJECTS. BIORETENTION AREAS ARE EXPECTED TO BE THE MOST COMMON GREEN INFRASTRUCTURE APPLICATION IN PUBLIC RIGHT-OF-WAY (ROW). THE PURPOSE OF THE BIORETENTIONAREA IS TO IMPROVE WATER QUALITY BY FILTRATION THROUGH THE BIOTREATMENT SOIL AND TO CONTROL RUNOFF PEAK FLOW RATES AND VOLUMES THROUGH STORAGE AND INFILTRATION.ENGINEER CHECKLIST (SHALL SPECIFY, AS APPLICABLE):BIORETENTION AREA WIDTH AND LENGTHDEPTH OF PONDINGAMOUNT OF FREEBOARD PROVIDEDDEPTH OF BIOTREATMENT SOIL (18" MIN)UNDERDRAIN SPECIFICATIONS AND LOCATION (IF FACILITY IS LINED PLACEUNDERDRAIN AT BOTTOM OF FACILITY)BIORETENTION SURFACE ELEVATION (TOP OF BIOTREATMENT SOIL) ATUPSLOPE AND DOWNSLOPE ENDS OF FACILITYCONTROL POINTS AT EVERY BIORETENTION WALL CORNER AND POINT OFTANGENCYDIMENSIONS AND DISTANCE TO EVERY INLET, OUTLET, CHECK DAM, SIDEWALKNOTCH, ETC.ELEVATIONS OF EVERY INLET, OVERFLOW RISER, STRUCTURE RIM AND INVERT,CHECK DAM, BIORETENTION AREA WALL CORNER, AND SIDEWALK NOTCHTYPE AND DESIGN OF BIORETENTION AREA COMPONENTS (E.G., EDGETREATMENTS, INLETS/GUTTER MODIFICATIONS, UTILITY CROSSINGS, LINER,AND PLANTING DETAILS)DEPTH AND TYPE OF NON-FLOATING MULCH (3" MIN)BIORETENTION AREA: NOTESGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
71DRAFTAppendix F City of Dublin Green Stormwater Infrastructure Plan
A
GI-3B
LENGTH, ENGINEERTO SPECIFYCOURTESYSTRIP, ENGINEERTO SPECIFY WIDTH3' (MIN) WIDTH,ENGINEER TOSPECIFYSIDEWALK ORLANDSCAPE PER CITYSTANDARD PLAN6"6"CURB AND GUTTER4"6"6"NOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES AND CHECKLIST.2.CHECK DAMS SHALL BE SPACED TO PROVIDE PONDING PER SITE SPECIFIC DESIGN (SEE DETAIL GI-7).3.LAY OUT DRAINAGE NOTCHES AS APPLICABLE TO PREVENT PONDING BEHIND BIORETENTION AREA WALL WITH 5' MAXIMUMSPACING BETWEEN NOTCHES.4.PROVIDE ONE UNDERDRAIN CLEANOUT PER BIORETENTION AREA (MIN). CLEANOUT REQUIRED AT UPSTREAM END AND PIPEANGLE POINTS EXCEEDING 45 DEGREES. LONGITUDINAL SLOPE OF PIPE SHALL BE 0.5% (MIN).DRAINAGE NOTCH (TYP), SEENOTE 3 AND DETAIL GI-3BBIORETENTION AREA WALL,SEE DETAIL GI-5INFLOWGUTTER SLOPEROADWAYWITH PARKINGTRENCH DRAIN INLET,SEE DETAIL GI-6BBIORETENTION AREA VEGETATION,SEE GI-1, NOTE 9OPTIONAL EROSIONPROTECTION, SEEGI-1, NOTE 10LATERAL OUTLET CONNECTIONTO STORM DRAINCONCRETE SPLASHAPRON (TYP), SEEDETAIL GI-6APEDESTRIAN PATH,ENGINEERTO SPECIFY WIDTHOVERFLOW RISER WITHGRATE, SEE DETAIL GI-4OPTIONAL ADDITIONAL INLET,ENGINEER TO SPECIFYOPTIONAL CHECKDAM, SEE NOTE 2UNDERDRAIN CLEANOUT,SEE NOTE 44" (MIN) PERFORATEDUNDERDRAINUNDERDRAIN CHECKDAM CROSSING, SEEGI-7, NOTE 2BIORETENTION AREA: PLAN VIEW WITH STREET PARKINGGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
72 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix FROADWAYCURB AND GUTTERSIDEWALK6"PARKING LANE4"3' (MIN)3' (MIN) WIDTH,DESIGNER TOSPECIFYTAPER CURB TO MATCHEXISTING GRADE (TYP)INFLOWNOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES AND CHECKLIST.2.CHECK DAMS SHALL BE SPACED TO PROVIDE PONDING PER SITE SPECIFIC DESIGN (SEE DETAIL GI-7).3.LAY OUT DRAINAGE NOTCHES TO PREVENT PONDING BEHIND BIORETENTION AREA WALL WITH 5' MAXIMUM SPACINGBETWEEN NOTCHES.4.PROVIDE ONE UNDERDRAIN CLEANOUT PER BIORETENTION AREA (MIN). CLEANOUT REQUIRED AT UPSTREAM ENDAND PIPE ANGLE POINTS EXCEEDING 45 DEGREES. LONGITUDINAL SLOPE OF PIPE SHALL BE 0.5% (MIN).CURB CUT INLET,SEE DETAIL GI-6COPTIONAL EROSIONPROTECTION, SEEGI-1, NOTE 10CONCRETESPLASH APRON,SEE DETAIL GI-6COPTIONAL CHECKDAM, SEE NOTE 2OPTIONAL ADDITIONALINLET, DESIGNER TOSPECIFYLATERAL OUTLET CONNECTIONTO STORM DRAINDRAINAGE NOTCH (TYP), SEENOTE 3 AND DETAIL GI-3BOVERFLOW RISER WITHGRATE, SEE DETAIL GI-4BIORETENTION AREA VEGETATION,SEE GI-1, NOTE 9UNDERDRAINCLEANOUT,SEE NOTE 44" (MIN) PERFORATEDUNDERDRAINBIORETENTION AREA: BULBOUT PLAN VIEWGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
73DRAFTAppendix F City of Dublin Green Stormwater Infrastructure PlanCURB AND GUTTERNOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES AND CHECKLIST.2.CHECK DAMS SHALL BE SPACED TO PROVIDE PONDING PER SITE SPECIFIC DESIGN (SEE DETAIL GI-7).3.PROVIDE ONE UNDERDRAIN CLEANOUT PER BIORETENTION AREA (MIN). CLEANOUT REQUIRED AT UPSTREAM END AND PIPE ANGLE POINTS EXCEEDING 45 DEGREES. LONGITUDINAL SLOPE OF PIPESHALL BE 0.5% (MIN).4.DESIGNERS TO REFERENCE AASHTO ROADSIDE SAFETY DESIGN REQUIREMENTS AND CONSIDER USE OF MEDIAN BIORETENTION AREAS IN RELATION TO STREET CLASSIFICATION AND STREET SPEEDS.5.A STORAGE VOLUME SAFETY FACTOR OF 1.5 SHALL BE INCLUDED IN THE DESIGN OF MEDIAN BIORETENTION AREAS TO PREVENT FLOODING.6.SLOPED SIDES (GI-3A) DEPICTED IN PLAN VIEW ABOVE, REFER TO GI-3B IF VERTICAL SIDE WALLS ARE USED.GUTTER SLOPECONCRETE SPLASHAPRON (TYP)BIORETENTION LENGTH,ENGINEER TO SPECIFYOPTIONAL CHECKDAM, SEE NOTE 2UNDERDRAIN CLEANOUT,SEE NOTE 3OVERFLOW RISER WITHGRATE, SEE DETAIL GI-4ROADWAY3' (MIN)BIORETENTIONWIDTH, ENGINEERTO SPECIFYLATERAL OUTLETCONNECTION TOSTORM DRAINUNDERDRAIN CHECK DAMCROSSING, SEE GI-7, NOTE 2VEGETATED BIORETENTION AREA,FLAT GRADE, SEE GI-1, NOTE 9VEGETATED SIDE SLOPES(3:1 MAX), SEE DETAIL GI-3A4" (MIN) PERFORATEDUNDERDRAINOPTIONAL UPSTREAMCONVEYANCE SWALE,ENGINEER TO SPECIFYGUTTER SLOPETRENCH DRAIN INLET (TYP),SEE DETAIL GI-6B, ENGINEERTO SPECIFY SPACINGROADWAY24"(MIN)SLOPE TRANSITION TO FLATBOTTOM, SEE DETAIL GI-3A24"(MIN)PERMEABLE PAVERS,REFER TO MEDIAN DETAILEROSION PROTECTION,REFER TO GI-1, NOTE 106" CURBPERMEABLE PAVERS,REFER TO MEDIAN DETAILBIORETENTION AREA: STREET MEDIANGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
74 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix F6" WIDTH BIORETENTIONAREA WALL (TYP),SEE DETAIL GI-5BIKE LANENOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES AND CHECKLIST.2.RAMP BIKE LANE UP ONTO BULBOUT AND SHIFT LANE OVER. MAXIMUM 1:5 HORIZONTAL TRANSITION RATE. TRANSITION GEOMETRY SHALL CONFORM TO CITYOF DUBLIN STANDARDS.3.HYDRAULIC CONNECTION OF SEPARATED BIORETENTION AREAS PROVIDED BY TRENCH DRAINS. ENGINEER TO SPECIFY, FOLLOWING FLOW AND STRUCTURALREQUIREMENTS.4.LAY OUT DRAINAGE NOTCHES AS APPLICABLE TO PREVENT PONDING BEHIND BIORETENTION AREA WALL WITH 5' MAXIMUM SPACING BETWEEN NOTCHES.5.PROVIDE ONE UNDERDRAIN CLEANOUT PER BIORETENTION AREA (MIN). CLEANOUT REQUIRED AT UPSTREAM END AND PIPE ANGLE POINTS EXCEEDING 45DEGREES. LONGITUDINAL SLOPE OF PIPE SHALL BE 0.5% (MIN). PIPE SLEEVES REQUIRED FOR UNDERDRAINS TRANSITIONING BETWEEN BIORETENTION AREAS.6.DRAWING GI-XX MODIFIED FROM THE BASMAA URBAN GREENING BAY AREA TYPICAL GI DETAILS FIGURE C-1.4.CONCRETESPLASH APRONINFLOWCURB CUT INLET,SEE DETAIL GI-6CPLANTING STRIPOPTIONAL EROSIONPROTECTION, SEEGI-1, NOTE 10FOREBAY, ENGINEERTO SPECIFY3:1 (MAX) VEGETATEDSIDE SLOPESIDEWALKBIKE LANE SHIFT,SEE NOTE 2TRENCH DRAIN (TYP), FLUSH WITHSURFACE, THROUGH BIORETENTIONAREA CURB WALLS, SEE NOTE 3DRAINAGE NOTCH(TYP), SEE NOTE 4 &DETAIL GI-3BPAVEMENT MARKERS,SEE STRIPING PLAN4" (MIN)PERFORATEDUNDERDRAINGUTTER CURB CUT,SEE DETAIL GI-6AUNDERDRAINCLEANOUT,SEE NOTE 5CURB ANDGUTTERLATERAL OUTLET CONNECTIONTO STORM DRAINBIORETENTIONAREA VEGETATION,SEE GI-1, NOTE 9ROADWAYOVERFLOW RISER WITHGRATE, SEE DETAIL GI-4BIORETENTION AREA: WITH BIKE LANE PLAN VIEWGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
75DRAFTAppendix F City of Dublin Green Stormwater Infrastructure Plan18" (MIN)12" (MIN)6" - 12" PONDING DEPTH,DESIGNER TO SPECIFY1' (MIN)BIOTREATMENT SOIL,SEE NOTE 5SCARIFIED ANDUNCOMPACTED SUBGRADE,SEE NOTES 2 & 32' (MIN)BOTTOM WIDTH2" (MIN) FREEBOARDNOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES ANDCHECKLIST.2.AVOID UNNECESSARY COMPACTION OF EXISTINGSUBGRADE BELOW AREA.3.SCARIFY SUBGRADE TO A DEPTH OF 3" (MIN)IMMEDIATELY PRIOR TO PLACEMENT OF CALTRANSCLASS 2 PERMEABLE MATERIAL STORAGE LAYER ANDBIOTREATMENT SOIL MATERIALS.4.AGGREGATE STORAGE LAYER COMPRISED OF 12" MINCALTRANS CLASS 2 PERMEABLE MATERIAL.5.REFER TO C.3 TECHNICAL GUIDANCE MANUAL (ACCWP)FOR BIOTREATMENT SOIL MIX SPECIFICATIONS.INSTALL BIOTREATMENT SOIL AT 85% COMPACTIONFOLLOWING BASMAA INSTALLATION GUIDANCE.6.ANGLE OF REPOSE VARIES PER GEOTECHNICALENGINEER RECOMMENDATIONS.7.UNDERDRAIN AND CLEAN OUT PIPE (1 MIN PERFACILITY) REQUIRED, REFER TO C.3 TECHNICALGUIDANCE MANUAL (ACCWP) FOR DESIGNCONSIDERATIONS. UNDERDRAINS SHOULD BEELEVATED 6" (MIN) WITHIN THE CALTRANS CLASS 2PERMEABLE MATERIAL STORAGE LAYER TO PROMOTEINFILTRATION. IN FACILITIES WITH AN IMPERMEABLELINER, THE UNDERDRAIN SHOULD BE PLACED AT THEBOTTOM OF THE CALTRANS CLASS 2 PERMEABLEMATERIAL STORAGE LAYER.8.THE UNDERDRAIN IN ALL FACILITIES LOCATED IN THEPUBLIC RIGHT-OF-WAY SHALL BE VIDEO RECORDEDAND PROVIDED TO THE CITY FOR REVIEW PRIOR TOPROJECT ACCEPTANCE.CALTRANS CLASS II PERMSTORAGE, SEE NOTE 4ROADWAY2' (MIN)X1ANGLE OF REPOSE,SEE NOTE 64" (MIN) PERFORATEDUNDERDRAIN, SEENOTES 7 & 8BACKFILL WITHNATIVE SOIL3" (TYP)MULCH13OVERFLOW RISER WITHGRATE, SEE DETAIL GI-4INLET NOTSHOWN, SEEDETAIL GI-6A &GI-6B6" (MIN)EDGE CONDITIONTO BE DESIGNEDBY ENGINEERPERMEABLE PAVERS,SEE DETAIL GI-5BIORETENTION AREA: SLOPED SIDES CROSS SECTIONGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
76 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix FNOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES AND CHECKLIST.2.AVOID UNNECESSARY COMPACTION OF EXISTING SUBGRADE BELOW BIORETENTION AREA.3.SCARIFY SUBGRADE TO A DEPTH OF 3" (MIN) IMMEDIATELY PRIOR TO PLACEMENT OF AGGREGATE STORAGE AND BIOTREATMENT SOIL MATERIAL.4.FOR STRUCTURAL SUPPORT, SUBGRADE UNDER WALLS ONLY COMPACTED PER ENGINEER SPECIFICATIONS.5.MAXIMUM DROP FROM TOP OF CURB TO TOP OF BIOTREATMENT SOIL SHALL INCLUDE CONSIDERATIONS FOR BIOTREATMENT SOIL SETTLEMENT. THEDROP IS THE SUM OF PONDING DEPTH (6" TYP), FREEBOARD (2" TYP), AND CURB HEIGHT (6" TYP).6"R 0.75" PER DPWSTANDARDS (TYP)6" (TYP) EXPOSED WALL12"(MIN)DRAINAGE NOTCH (TYP)SLOPE TO BIORETENTION AREAKEY OR EXPANSION JOINT PERCITY OF DUBLIN APPROVAL (TYP), ENGINEERTO SPECIFY EDGE CONNECTIONBIORETENTION AREA WITH VERTICAL SIDE WALLSAFRONT VIEWDRAINAGE NOTCH DETAIL4"SIDE VIEW18"(MIN)2" FREEBOARDOVERFLOW RISER WITHGRATE, SEE DETAIL GI-4SCARIFIED AND UNCOMPACTEDSUBGRADE, SEE NOTES 2 & 3BIOTREATMENT SOIL,SEE GI-3A, NOTE 5COURTESY STRIP,ENGINEER TOSPECIFY WIDTHCURB ANDGUTTERROADWAYWITH PARKING3' (MIN)14" MAX DROP,SEE NOTE 5EDGE TREATMENT (TYP),SEE DETAIL GI-56" (MIN)1" DRAINAGE NOTCHSIDEWALK PER CITYSTANDARD PLAN2" FREEBOARD6" (MAX) PONDINGDEPTH, ENGINEERTO SPECIFYCOMPACTED SUBGRADE,SEE NOTE 44" (MIN) PERFORATED UNDERDRAIN,SEE GI-3A, NOTES 7 & 8CALTRANS CLASS II PERMSTORAGE, SEE GI-3A, NOTE 4BIORETENTION AREA: VERTICAL SIDE WALL CROSS SECTIONGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
77DRAFTAppendix F City of Dublin Green Stormwater Infrastructure PlanCAST IRON GRATE, SEE NOTE 8ENGINEER TO SPECIFYOVERFLOWSTRUCTURE4" (MIN) PERFORATEDUNDERDRAIN, SEEGI-3A, NOTES 7 & 8ENGINEER TO SPECIFYELEVATION FOR 6 - 12"PONDING DEPTHWALLPENETRATIONBELL AND SPIGOTJOINT (TYP) OROTHER APPROVEDALTERNATIVE12" (MIN)SEE NOTE 36" (MIN)6" (MIN)GRAVEL BASEASTM NO. 57OPTIONAL GROUTEDCOBBLES, SEE NOTE 10DESIGN PONDINGELEVATIONNOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES AND CHECKLIST.2.ALL MATERIAL AND WORKMANSHIP FOR OVERFLOW STRUCTURES SHALL CONFORMTO CITY OF DUBLIN STANDARDS.3.DESIGN OVERFLOW WEIR AND OUTLET PIPE TO CONVEY 10-YR, 24-HR STORM FLOWOR DESIGN INLET TO DIVERT FLOWS LARGER THAN THE DESIGN STORM DIRECTLY TOTHE STORM DRAIN. LOCATE ALL OVERFLOW PIPES AT AN ELEVATION HIGHER THANTHE STORM SEWER HYDRAULIC GRADE LINE TO PREVENT BACKFLOW INTO THEBIORETENTION FACILITY.4.STORM DRAIN OUTLET PIPES SHALL BE SIZED TO MEET HYDRAULIC REQUIREMENTSWITH APPROPRIATE COVER DEPTH AND PIPE MATERIAL.5.PERFORATED UNDERDRAINS WITH CLEANOUT PIPES ARE REQUIRED.6.MAINTENANCE ACCESS IS REQUIRED FOR ALL OUTLET STRUCTURES AND CLEANOUTFACILITIES. 12" (MIN) CLEARANCE WITHIN OVERFLOW STRUCTURE SHALL BEPROVIDED FOR MAINTENANCE ACCESS.7.ENGINEER SHALL EVALUATE BUOYANCY OF STRUCTURES FOR SITE SPECIFICAPPLICATION AND SPECIFY THICKENED OR EXTENDED BASE / ANTI-FLOTATIONCOLLAR, AS NECESSARY.8.SIZE OF GRATE SHALL MATCH SIZE OF RISER SPECIFIED IN PLANS, SHALL BEREMOVABLE TO PROVIDE MAINTENANCE ACCESS, AND SHALL BE BOLTED IN PLACEOR OUTFITTED WITH APPROVED TAMPER-RESISTANT LOCKING MECHANISM.MAXIMUM GRATE OPENING SHALL BE 2".9.IF INTERIOR DEPTH OF OVERFLOW STRUCTURE EXCEEDS 5', A PERMANENT BOLTEDLADDER AND MINIMUM CLEAR SPACE OF 30" BY 30" SHALL BE PROVIDED FORMAINTENANCE ACCESS.10.MINIMUM DIAMETER OF OPTIONAL GROUTED COBBLES SHALL BE LARGER THANMAXIMUM GRATE OPENING.11.GROUT ALL PENETRATIONS, CRACKS, SEAMS, AND JOINTS WITH CLASS "C" MORTAR.6" (MIN)LATERAL OUTLETCONNECTION TOSTORM DRAINBIORETENTION COMPONENTS: OUTLET DETAILGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
78 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix FEXTENDED BIORETENTION AREA WALL WITH LATERAL BRACING23" (MIN) COVER,SEE NOTE 4DROADWAY WITHOUTPARKINGSIDEWALK / PLAZALATERAL BRACING,SEE NOTE 4BKEY OR EXPANSIONJOINTCONCRETE BIORETENTIONAREA WALL, SEE DETAILGI-3BCOMBINED CURB AND PARKINGSTRIP OR GUTTER WITHMONOLITHIC WALL EXTENSION,SEE NOTE 410' (MAX)6"#4 @ 12" O.C.(HOR), (3) MIN#4 @ 12" O.C.(VERT) @ ℄SEE NOTE 4ESTANDARD CURB EDGE AT BIORETENTION BASIN12' (MIN)ROADWAYWITHOUT PARKINGCURB AND PARKINGSTRIP OR GUTTERPONDING DEPTH,EQUAL TO ELEVATIONOF OUTLETANGLE OF REPOSESEE NOTE 3C6"BIORETENTION BASIN,SEE DETAIL GI-3A1X13BACKFILL WITHNATIVE SOILNOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES AND CHECKLIST.2.THE ENGINEER SHALL ADAPT EDGE TREATMENT DESIGN TO ADDRESS SITESPECIFIC CONSTRAINTS TO EFFECTIVELY STABILIZE ADJACENT PAVEMENTAND MINIMIZE LATERAL MOVEMENT OF WATER.3.STANDARD CURB EDGE (WHEN SPACE AVAILABLE):A.PERMEABLE PAVER STRIP (2' MIN WIDTH) REQUIRED IF SPRAYIRRIGATION IS USED TO COMPLY WITH WATER EFFICIENT LANDSCAPEORDINANCE..B.REFER TO CITY OF DUBLIN MEDIAN DETAIL (TBD) FOR PERMEABLE STRIPAND UNDERLYING AGGREGATE SPECIFICATIONS.C.ANGLE OF REPOSE VARIES PER GEOTECHNICAL ENGINEERSRECOMMENDATIONS.4. VERTICAL SIDE WALLS (WHEN SPACE LIMITED):A.ALL BIORETENTION AREA WALLS SHALL EXTEND TO BOTTOM OFAGGREGATE STORAGE LAYER OR DEEPER. MINIMUM DEPTHS SHALL BEDESIGNED TO PREVENT LATERAL SEEPAGE INTO THE ADJACENTPAVEMENT SECTION.B.FOOTING OR LATERAL BRACING SHALL SHALL BE DESIGNED BY THEENGINEER TO WITHSTAND ANTICIPATED LOADING ASSUMING NOREACTIVE FORCES FROM THE UNCOMPACTED BIOTREATMENT SOIL.C.BIORETENTION AREA WALLS EXTENDING MORE THAN 36" BELOWADJACENT LOAD-BEARING SURFACE, OR WHEN LOCATED ADJACENT TOPAVERS, SHALL HAVE FOOTING OR LATERAL BRACING. FOOTING ORLATERAL BRACING MAY BE EXCLUDED ONLY IF THE ENGINEERDEMONSTRATES THAT THE PROPOSED WALL DESIGN MEETS LOADINGREQUIREMENTS. WALL SHALL NOT ENCROACH INTO TREATMENT AREA.D.CONTRACTOR TO PROVIDE 3" MINIMUM COVER OVER ALL LATERALBRACING FOR PLANT ESTABLISHMENT.E.ALL CONSTRUCTION COLD JOINTS SHALL INCORPORATE EPOXY,DOWEL/TIE BAR, KEYWAY, OR WATER STOP.WALL SHALL EXTEND ATLEAST 6' BELOW BOTTOMOF ROAD SECTIONPERMEABLE PAVERS, SEE NOTE 3BIORETENTION COMPONENTS: EDGE TREATMENT DETAILGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
79DRAFTAppendix F City of Dublin Green Stormwater Infrastructure Plan PLANMATCHCURBWIDTH18"(MIN)12" (MIN)3' (MIN)CONCRETE SPLASHAPRON, NOTINTEGRAL TO CURBROADWAYSECTION AGUTTER UPSLOPE ANDDOWNSLOPE OF CURB CUTMATCH HEIGHT OF CURBUPSLOPE AND DOWNSLOPE OFCURB CUTCONCRETESPLASH APRONOPTIONAL EROSIONPROTECTION, SEE GI-1,NOTE 101" (MIN)ISOMETRICCURBINFLOWBIORETENTION AREASPLASH APRONTAPER GUTTER AT CURB CUT TOMATCH GUTTER SLOPE UPSLOPEAND DOWNSLOPE OF CURB CUT.SLOPE2" GUTTER DEPRESSIONAT FLOWLINENOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES AND CHECKLIST.2.CURB CUT INLETS SHALL BE ADEQUATELY SIZED, SPACED, AND SLOPED TO MEET HYDRAULIC REQUIREMENTS. THECURB CUT OPENING WIDTH SHALL BE SIZED BASED ON THE CATCHMENT AREA, LONGITUDINAL SLOPE ALONG THECURB, AND THE CROSS SLOPE OF THE GUTTER OR ADJACENT PAVEMENT AT THE INLET. SEE SIZING EQUATIONS ANDNOMOGRAPHS FOR CURB OPENING INLETS IN THE U.S. DEPARTMENT OF TRANSPORTATION HYDRAULIC ENGINEERINGCIRCULAR NO. 27.3.BOND NEW CURB AND GUTTER TO EXISTING CURB AND GUTTER WITH EPOXY AND DOWEL CONNECTION.4.METAL INLET ASSEMBLY SHALL BE HOT-DIP GAVANIZED IN ACCORDANCE WITH ASTM A-123.6" (MIN), ENGINEERTO SPECIFYSEE NOTE 2ROADWAYA-DEPRESSED GUTTER2" AT OPENINGB
ELEVATIONSECTION BMETAL INLET ASSEMBLYB
3"3"18"6"12"3"0.5"0.5" X 4" F500HEADED CONCRETEANCHOR CENTER ONEND PLATES0.5" DIA. WEEPHOLES (TYP)MINIMUM 18"THICK END PLATEHSS 6x 2x 18"316" DIA. WEEPHOLES (TYP)FULLWIDTH OFCURB CUTMATCHGUTTERWIDTHBIORETENTION COMPONENTS: GUTTER CURB CUT INLET DETAILGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
80 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix FISOMETRICGRATECURBCOURTESY ZONEGRATECURB ANDGUTTERBIORETENTIONAREAOUTLET TOBIORETENTION AREA#5 REBAR(MIN)CONCRETESPLASH APRON,NOT INTEGRALTO CURBROADWAYWITH PARKINGSLOPE, SEENOTE 4SECTION A1" (MIN)1" (MIN)RAISED BIORETENTION AREA WALLBRIDGING OVER CHANNEL OPENINGCONCRETESPLASH APRONMATCH ADJACENTSIDEWALK SLOPECONCRETECHANNELEXTEND TRENCH GRATE TO FACE OFRAISED BIORETENTION AREA WALLBIORETENTION AREASLOPE2" GUTTERDEPRESSIONINFLOWSLOPE TO DRAINA-B-6" (MIN)ENGINEERTO SPECIFY#5 REBAR (MIN)1.REFER TO GI-1 NOTES FOR GUIDELINES ANDCHECKLIST.2.ALL MATERIAL AND WORKMANSHIP FORTRENCH DRAIN ASSEMBLY SHALL CONFORMTO CITY OF DUBLIN STANDARDS.3.TRENCH DRAIN INLETS SHALL BEADEQUATELY SIZED, SPACED, AND SLOPEDTO MEET HYDRAULIC REQUIREMENTS. SEENOTE 2 DETAIL GI-6A FOR REFERENCE.4.SLOPE TO PROVIDE AT LEAST 1" DROP OVERLENGTH OF CHANNEL OR A MINIMUM OF 2%,WHICHEVER IS LARGER.5.ALL TRENCH GRATES SHALL BE REMOVABLE,RATED PER THE ANTICIPATED LOADING, ANDBOLTED IN PLACE OR OUTFITTED WITHAPPROVED TAMPER-RESISTANT LOCKINGMECHANISM, FLUSH OR RECESSED IN GRATE.6.BOND NEW CURB AND GUTTER TO EXISTINGCURB AND GUTTER WITH EPOXY AND DOWELCONNECTION.7.HORIZONTAL CONTROL JOINTS SHALL BEPROVIDED EVERY 10' (LINEAR), OR PERMANUFACTURER'S RECOMMENDATIONS.8.APPLY EPOXY BONDING AGENT AT ALLTRENCH DRAIN CONSTRUCTION COLDJOINTS.9.INLET CURB CUT AND CONCRETE CHANNELWIDTH SHALL BE SIZED TO ACCOUNT FORCATCHMENT AREA AND GUTTER SLOPE.GUTTER MODIFICATIONAT INLET, SEE DETAILGI-6AGUTTERMODIFICATIONAT INLET, SEEDETAIL GI-6AGUTTERMODIFICATIONAT INLET, SEEDETAIL GI-6ANOTES:OPTIONAL EROSIONPROTECTION, SEE GI-1,NOTE 10ASTM #57GRAVEL BASEPREPARED ANDCOMPACTED SOIL18" (MIN) WIDTHCAST IRON TRENCHGRATE, SEE NOTE 3#3 @ 12" O.C.(HOR) (5) MINKEY OR EXPANSIONJOINT10"-16" (TYP)DESIGNERTO SPECIFY,SEE NOTE 76" (MIN)CONCRETECHANNELSECTION BANCHORAAFRAME VARIES PERMANUFACTURER'SRECOMMENDATIONSA#3 @ 12" O.C.MIN (3) #36" (MIN)6" (MIN)FLUSH EDGES (TYP)BIORETENTION COMPONENTS: TRENCH DRAIN CURB CUT INLET DETAILGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
81DRAFTAppendix F City of Dublin Green Stormwater Infrastructure Plan ROADWAYPLANISOMETRICCURB ANDGUTTERBIORETENTIONAREAGUTTER MODIFICATION ATINLET, SEE DETAIL GI-6ACURBBIORETENTIONAREA WALLCONCRETESPLASH APRONSECTION ACONCRETE SPLASHAPRON, INTEGRALTO CURBOPTIONAL EROSIONPROTECTION, SEE GI-1,NOTE 101" (MIN)SLOPE2" GUTTERDEPRESSIONNOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES AND CHECKLIST.2.ALL MATERIAL AND WORKMANSHIP FOR CURB CUTS SHALL CONFORMTO CITY OF DUBLIN STANDARDS.3.CURB CUT INLETS SHALL BE ADEQUATELY SIZED, SPACED, ANDSLOPED TO MEET HYDRAULIC REQUIREMENTS. SEE NOTE 2, DETAILGI-6A FOR REFERENCE.4.BOND NEW CURB AND GUTTER TO EXISTING CURB AND GUTTER WITHEPOXY AND DOWEL CONNECTION.TOP OF BIORETENTIONAREA WALLTOP OF CURBBIORETENTIONAREA WALLSIDEWALK12" (MIN)SEENOTE 312" (MIN)6" (MIN), ENGINEERTO SPECIFYINFLOWTAPER CURB TO MATCHGRADE, ALIGN WITHGUTTER TERMINATIONCONCRETESPLASH APRONA-TAPER TOMATCH GRADEOPTIONAL EROSIONPROTECTION, SEEGI-1, NOTE 10BIORETENTION COMPONENTS: CURB CUT AT BULBOUT INLET DETAILGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
82 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix F2" FREEBOARD6" (MIN)NOTES:1.REFER TO GI-1 NOTES FOR GUIDELINES AND CHECKLIST.2.UNDERDRAIN TO PASS THROUGH CHECK DAM IN NON-PERFORATEDHDPE SDR 17 PIPE. PIPE FITTINGS SHALL BE USED TO ACCOMMODATECHANGES IN GRADE, AS NEEDED.3.HEIGHT AND SPACING OF CHECK DAMS SHALL BE ESTABLISHEDBASED ON THE PONDING DEPTH REQUIRED TO MEET PROJECTHYDROLOGIC PERFORMANCE GOALS AND THE MAXIMUM DESIREDDROP FROM THE SURROUNDING GRADE TO THE FACILITY BOTTOM.4.ALL MATERIAL AND WORKMANSHIP FOR CHECK DAM ASSEMBLY SHALLCONFORM TO CITY OF DUBLIN STANDARD SPECIFICATIONS.5.CONCRETE CHECK DAM SHALL BE CONTINUOUS (NO JOINTS) ANDREINFORCED WITH #4 BAR, PLACED AT 18" ON CENTER, EACH WAY.6.CONCRETE CHECK DAM SHALL MEET STRUCTURAL REQUIREMENTSFOR LATERAL BRACING WHEN USED AS LATERAL BRACING.COORDINATE WITH ENGINEER.7.TOP OF CHECK DAM TO BE LEVEL WITH CREST ELEVATION MATCHINGPONDING ELEVATION UNLESS NOTCH SIZED TO CONVEY DESIGNFLOWS PROVIDED.8.GROUT ALL PENETRATIONS, CRACKS, SEAMS, AND JOINTS WITHCLASS "C" MORTAR.TOP OF CHECK DAM, SEE NOTE 3UNDERDRAIN,SEE NOTE 2TOP OFSIDEWALKTOP OF RAISED BIORETENTION AREA WALLCONCRETE CHECK DAM,SEE NOTES 3 TO 8UNDERDRAIN,SEE NOTE 2 ANDGI-3A, NOTE 7PROFILE - CONCRETE CHECK DAM2SECTION - CONCRETE CHECK DAM1CONCRETE CHECK DAM,SEE NOTES 3 T0 8UNDERDRAIN PIPEFITTINGSSEE NOTE 23" (MIN) KEY12" (MIN)KEY OR EXPANSION JOINT (TYP)WATER STOP, BOTH SIDES (TYP)(2) #4 W/ 90° HOOK @ ENDS10' (MAX)3" (MIN) KEYOPTIONAL GROUTEDCOBBLES, AS NEEDEDFOR ENERGY DISSIPATIONPONDING ELEVATION,ENGINEER TO SPECIFYBIORETENTION AREA WALLREINFORCING (TYP), SEEDETAIL GI-5WALLPENETRATIONDRAINAGE NOTCH (TYP),SEE DETAIL GI-3BHEIGHT AS SHOWNON PROJECT PLANSBIORETENTION COMPONENTS: CHECK DAM DETAILGREEN INFRASTRUCTURETYPICAL DETAILSCITY OF DUBLIN PUBLIC WORKSSCALE: NOT TO SCALEDATE:MAY 11, 2018DRAWN BY:K. K.CHECKED BY:APPROVED:PUBLIC WORKS DIRECTORA. R.
83DRAFTAppendix G City of Dublin Green Stormwater Infrastructure Plan
Appendix G
GENERAL GUIDELINES AND IMPLEMENTATION CHECKLISTS FOR GSI PROJECTS
G-1 Hydraulic Sizing Requirements
Provision C.3.j.i.(2)(g) of the MRP states that GSI projects are required to meet the treatment and hydromodification
management (HM) sizing requirements included in Provisions C.3.c and C.3.d of the MRP. However, an exception
to this requirement is provided in Provision C.3.j.i.(2)(g) for street projects that are not Regulated Projects under
Provision C.3.b (“non-Regulated Projects”). An alternate sizing approach for non-Regulated constrained street
projects has been developed by the Bay Area Stormwater Management Agencies Association and the Water Board
has provided verbal approval for the approach. The BASMAA alternate sizing approach guidelines will be available
on-line when the approach is formally approved by the Water Board. These guidelines are not intended for use by
Regulated Projects as defined in Provision C.3.b of the MRP.
Additional design guidance for GSI facilities, which are also referred to as low impact development (LID) stormwater
treatment facilities, is provided in Chapters 5 and 6 of the Alameda Countywide Clean Water Program’s C.3
Technical Guidance, which may be downloaded at, www.cleanwaterprogram.org.
G-2 Guidelines Addressing Urban Forestry in Public Right of Way
Increasing the planting of street trees is anticipated to benefit local water quality, air quality, energy efficiency,
and property values. GSI projects should incorporate measures to preserve existing street trees and promote the
planting of new street trees. The following measures should be incorporated, as appropriate:
• Prioritize the preservation of existing mature trees.
• Replace any mature trees that are removed by the project.
• Maximize the planting of new trees.
• The planting of trees within a GSI facility should follow guidance, including the identification of appropriate
species, provided in Appendix B of the ACCWP C.3 Technical Guidance.
• Incorporate trees in landscaped areas within parking lots.
G-3 Bay Friendly Landscape Principles
Bay-Friendly landscapes create and maintain healthy, beautiful and vibrant landscapes by:
• Landscaping in harmony with the natural conditions of the San Francisco Bay watershed
• Reducing waste and recycling materials
• Nurturing healthy soils while reducing fertilizer use
• Conserving water, energy and topsoil
• Using integrated pest management to minimize chemical use
84 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix G
• Reducing stormwater runoff and air pollution
• Protecting and enhancing wildlife habitat and diversity
Designing qualified GSI facilities to be a rated Bay Friendly Landscape may enable portions of the facility to
be funded with Measure D Funds (the Alameda County Waste Reduction and Recycling Act). Bay Friendly
Landscape design, construction and maintenance practices should be considered from project conception. For
more information on Bay Friendly Landscape principles, refer to Rescape California at https://rescapeca.org/.
G-4 Guidelines for Coordination of Projects
Installing GSI components at a project prior to the completion of that project, or the construction of an adjacent
project, has the potential to degrade the functioning of the GSI facility. Street improvement or other infrastructure
projects, the development of public parcels, and other public and private projects should therefore include
coordination of construction schedules to minimize impacts to GSI.
The following measures should be implemented in all GSI projects to protect investments in GSI:
1. Do not use GSI facilities as temporary sediment basins during construction.
2. Include protections for GSI in erosion control plans.
3. Protect installed GSI facilities from construction runoff and keep offline until the contributing drainage area
is stabilized.
4. Contractors are encouraged to construct GSI facilities at the end of a project, to help protect the facilities from
construction-related impacts.
G-5 Stormwater Management Plan Content
This document was created to inform Staff and project proponents about required content for stormwater
management plans that apply to GSI projects. It includes requirements for both the entitlement stage and building
permit/improvement plan stage.
G-6 Public Works Improvement Plans General Notes
The Public Works improvement plan general notes include notes that apply during design, construction, project
sign-off, and at post-construction.
G-7 Stormwater Review Checklist
This document was created to assist Staff during plan review. Staff use the tip sheet as a reminder for items to check
while conducting stormwater plan review.
G-8 Landscape Plan Checklist
The City created this checklist to guide Staff through the Water Efficient Landscape Ordinance plan review. Steps
for checking conformance with GSI plans are included in the checklist.
G-9 Inspector Final Inspection Checklist
Dublin developed the Inspector Final Inspection Checklist to ensure that inspectors verify all components of a
project prior to final project acceptance, including checking for critical GSI information.
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G-10 C.3 Operations & Maintenance Inspection Form
Staff use the C.3 Operations & Maintenance (O&M) Inspection Form developed by the ACCWP for the initial
project inspection conducted at project close-out and during regular O&M inspections. As described in Section
4.3, Staff also conduct inspections of GSI facilities during critical points of construction.
G-11 Worksheet for Identifying Green Infrastructure Potential in Municipal Cap-
ital Improvement Program Projects
Staff is using this worksheet developed by ACCWP, which was based on the guidance developed by the Bay Area
Municipal Management Agencies Association, to help identify for which capital improvement projects it is feasible
to include green stormwater infrastructure. The feasibility is initially conducted to determine if there are technical
constraints that would limit the inclusion of GSI; a funding analysis is conducted after feasibility is determined.
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Appendix H
FUNDING AND FINANCING STRATEGY DOCUMENTS
Prepared for
City of Dublin
100 Civic Plaza
Dublin, California 94568
FINAL
ALTERNATIVE COMPLIANCE HANDBOOK
Prepared by
1111 Broadway, 6th Floor
Oakland, California 94607
Project Number: WW2298
June 2019
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City of Dublin Alternative Compliance Handbook
ii
TABLE OF CONTENTS
1. ALTERNATIVE COMPLIANCE HANDBOOK OVERVIEW ......................... 1
2. REGULATORY REQUIREMENTS ................................................................... 1
2.1 Green Stormwater Infrastructure Plan Requirements .................................. 3
3. ALTERNATIVE COMPLIANCE PROGRAM BACKGROUND ...................... 4
3.1 Background .................................................................................................. 4
3.2 Examples of Alternative Compliance Approaches and Programs ............... 6
4. DEVELOPING AN ALTERNATIVE COMPLIANCE PROGRAM .................. 9
4.1 Initial Considerations ................................................................................... 9
4.2 Potential Studies Needed ........................................................................... 12
4.3 Steps Needed to Develop a Program ......................................................... 13
5. POLICY OR ORDINANCE OVERVIEW ......................................................... 14
5.1 Existing Policies and Ordinances .............................................................. 15
6. COSTS ................................................................................................................ 16
7. RECOMMENDED NEXT STEPS ..................................................................... 17
8. REFERENCES ................................................................................................... 17
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LIST OF ACRONYMS AND ABBREVIATIONS
BMP best management practice
DCMR District of Columbia Municipal Regulations
DOEE Department of Energy and Environment
FSP fine sediment particles
GSI green stormwater infrastructure
LID low-impact development
LIDI Low Impact Development Initiative
MRP Municipal Regional Stormwater Permit
MS4 Municipal Separate Storm Sewer
P3s Public-Private Partnerships
PDPs Priority Development/Redevelopment Projects
Region 9 Region 9 Water Quality Control Board
SFPUC San Francisco Public Utilities Commission
TMDLs total maximum daily loads
USEPA United States Environmental Protection Agency
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1. ALTERNATIVE COMPLIANCE HANDBOOK OVERVIEW
This Alternative Compliance Handbook has been prepared for the City of Dublin (City)
to provide information on the requirements and resources needed for initiating an
alternative compliance program in accordance with the San Francisco Bay Regional
Water Quality Control Board Municipal Regional Stormwater NPDES Permit (MRP;
Order No R2-2015-0049). This Alternative Compliance Handbook provides background
and regulatory information about alternative compliance programs for stormwater,
example programs, and recommended next steps for the City for developing an alternative
compliance program for stormwater.
This Alternative Compliance Handbook is organized as follows:
• Section 2 provides a summary of the requirements included in the MRP;
• Section 3 provides background information on stormwater alternative compliance
programs, as well as descriptions of other alternative compliance programs across
the country;
• Section 4 provides considerations, studies, and recommended steps for
developing an alternative compliance program for stormwater;
• Section 5 includes a summary of stormwater alternative compliance policy or
ordinance contents and examples;
• Section 6 describes cost considerations for program development; and
• Section 7 provides a suggested timeline for program exploration and/or
development for the City.
2. REGULATORY REQUIREMENTS
The MRP gives Permittees the authority to allow regulated projects to provide alternative
compliance with the stormwater treatment provisions of C.3.b using low-impact
development (LID) treatment at an offsite location or payment of an In-Lieu Fee. The
specific MRP language corresponding to alternative compliance and In-Lieu Fee is
included below.
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“C.3.e. Alternative or In-Lieu Compliance with Provision C.3.b.
i. The Permittees may allow a Regulated Project to provide alternative
compliance with Provision C.3.b in accordance with one of the two options
listed below:
(1) Option 1: LID Treatment at an Offsite Location
Treat a portion of the amount of runoff identified in Provision C.3.d for the
Regulated Project’s drainage area with LID treatment measures onsite or
with LID treatment measures at a joint stormwater treatment facility and
treat the remaining portion of the Provision C.3.d runoff with LID
treatment measures at an offsite project in the same watershed. The offsite
LID treatment measures must provide hydraulically-sized treatment (in
accordance with Provision C.3.d) of an equivalent quantity of both
stormwater runoff and pollutant loading and achieve a net environmental
benefit.
(2) Option 2: Payment of In-Lieu Fees
Treat a portion of the amount of runoff identified in Provision C.3.d for the
Regulated Project’s drainage area with LID treatment measures onsite or
with LID treatment measures at a joint stormwater treatment facility and
pay equivalent In-Lieu Fees4 to treat the remaining portion of the Provision
C.3.d runoff with LID treatment measures at a Regional Project.5 The
Regional Project must achieve a net environmental benefit.
(3) For the alternative compliance options described in Provision
C.3.e.i.(1) and (2) above, offsite and Regional Projects must be completed
within three years after the end of construction of the Regulated Project.
However, the timeline for completion of a Regional Project may be
extended, up to five years after the completion of the Regulated Project,
with prior Executive Officer approval. Executive Officer approval will be
granted contingent upon a demonstration of good faith efforts to implement
the Regional Project, such as having funds encumbered and applying for
the appropriate regulatory permits.”
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A Regional Project is defined in the MRP as:
“Regional Project - A regional or municipal stormwater treatment facility
that discharges into the same watershed as the Regulated Project.”
Reporting requirements for alternative compliance are included as follows in the MRP:
“C.3.b.iv (2) Annual Reporting
(m) Alternative compliance measures for Regulated Project (if applicable)
(i) If alternative compliance will be provided at an offsite location in
accordance with Provision C.3.e.i.(1), include information required in
Provision C.3.b.iv.(2)(a) – (l) for the offsite project;
and
(ii) If alternative compliance will be provided by paying In-Lieu Fees in
accordance with Provision C.3.e.i.(2), provide information required in
Provision C.3.b.iv.(2)(a) – (l) for the Regional Project. Additionally,
provide a summary of the Regional Project’s goals, duration, estimated
completion date, total estimated cost of the Regional Project, and estimated
monetary contribution from the Regulated Project to the Regional Project”
2.1 Green Stormwater Infrastructure Plan Requirements
The MRP also requires that Permittees submit a Green Infrastructure Plan (otherwise
known as, and hereinafter referred to as, a Green Stormwater Infrastructure Plan) during
the current permit term. Alternative compliance, In-Lieu Fee, and/or water quality credit
trading programs may be used to help implement the Green Stormwater Infrastructure
Plan(s) by providing a potential means to fund, at least partially, or cause to be
constructed, public green stormwater infrastructure projects. Components of the GI Plan
that could be related to and/or require integration with an alternative compliance program
may include (paraphrased from C.3.j.i.(2)):
a) A mechanism to prioritize and map areas for potential and planned projects for
the following time frames (consistent with assessing load reductions specified in
Provisions C.11 and C.12):
a. By 2020
b. By 2030
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c. By 2040
b) Outputs from the selected mechanism, including but not limited to project
prioritization criteria, maps, lists, and other information.
c) Targets for the amount of impervious surface (public and private) to be retrofitted
within the identified time frames (i.e., by 2020, by 2030, and by 2040).
d) A process for tracking and mapping completed projects and making the
information publicly available.
e) General guidelines for streetscape and project design and construction.
f) Standard specifications and, as appropriate, typical design details and related
information necessary to incorporate green stormwater infrastructure projects into
the Permittee’s jurisdiction.
g) Requirements that projects be designed to meet the treatment and
hydromodification sizing requirements in Provisions C.3.c and C.3.d of the MRP.
h) A summary of planning documents the Permittee has updated or otherwise
modified to appropriately incorporate green stormwater infrastructure
requirements.
i) To the extent not addressed with other components, a workplan identifying how
the Permittee will ensure that green stormwater infrastructure and low impact
development measures are appropriately included in future plans.
j) A workplan to complete prioritized projects identified as part of a Provision C.3.e
Alternative Compliance program or part of Provision C.3.j Early Implementation.
k) An evaluation of prioritized project funding options.
The Green Stormwater Infrastructure Plan must be developed with consideration of meeting
the green infrastructure load reduction requirements included in Provisions C.11 and C.12
(i.e., required mercury and PCBs load reductions).
The MRP also requires a Reasonable Assurance Analysis to demonstrate that the MRP
Permittees will collectively achieve a mercury load reduction of 10 kilograms per year
and a PCBs load reduction of 3 kilograms per year from implementation of green
stormwater infrastructure projects by 2040.
3. ALTERNATIVE COMPLIANCE PROGRAM BACKGROUND
3.1 Background
Alternative compliance programs are typically optional jurisdiction-specific or regional
programs that allow municipalities or other Permittees to develop or redevelop projects
using offsite mitigation for stormwater. These programs are enabled by specific
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provisions within a Municipal Separate Storm Sewer (MS4) permit and are intended to
allow for increased flexibility and efficiency (i.e., time or cost) in addressing stormwater
requirements. Alternative compliance programs vary but generally allow a project to
satisfy a portion, or all, of its stormwater treatment obligations at an offsite location.
Offsite locations that could be considered in the City of Dublin include those identified
in the Green Stormwater Infrastructure Plan.
A summary of terms relevant to this Alternative Compliance Handbook are provided:
• Offsite mitigation – Defined for the purposes of this Alternative Compliance
Handbook as:
The use of best management practices (BMPs) at a location outside the
development or redevelopment footprint of a project to satisfy stormwater
treatment requirements in place of, or to supplement the use of, onsite BMPs.
• In-Lieu Fees – Defined in the MRP as:
“Monetary amount necessary to provide both hydraulically-sized treatment (in
accordance with Provision C.3.d) with LID treatment measures of an equivalent
quantity of stormwater runoff and pollutant loading, and a proportional share of
the operation and maintenance costs of the Regional Project.”
• Water Quality Trading – The Water Quality Trading Toolkit (United States
Environmental Protection Agency [USEPA], 2007) defines water quality trading
as follows:
“The use of water quality Credits generated at one location for compliance with
water quality-based requirements at another location within a trading area.”
Water quality trading can be a particularly useful tool in watersheds with
established total maximum daily loads (TMDLs). The TMDL, however, will
largely dictate the type and geographic extent of allowed trading. Furthermore,
tradable credits can only be generated when a source reduces loadings below the
allocation set by the TMDL.
• Public-Private Partnerships (P3s) – P3s are performance-based business ventures,
funded and operated through partnerships by and between government and the
private sector. Stormwater P3s are intended to help communities optimize limited
labor resources, meet compliance obligations, and control risk and finances to
help build and maintain public infrastructure. A P3’s role in an alternative
compliance program is typically as the implementer of a credit generating or In-
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Lieu Fee BMP.
3.2 Examples of Alternative Compliance Approaches and Programs
3.2.1 City of Emeryville, California
The City of Emeryville provides a local example of alternative compliance. Rather than
develop a full alternative compliance program, the City implemented a single alternative
compliance arrangement as the need arose. The City of Emeryville entered into an
agreement with a private developer for funding of off-site LID to meet alternative
compliance with the MRP for a redevelopment project (City of Emeryville, 2017).
Eight potential locations to site GSI in the watershed were identified, and five were selected
for implementation by the City Engineer. The selection by the City Engineer was based
on a combination of factors, including utility locations, traffic and parking needs, and
beautification. Street trees (camphor trees) in poor condition that were identified for
removal through the capital improvement project (CIP) list will also be removed as part
of the construction of the projects.
This approach was successful because the potential locations of public GSI retrofit could
be quickly assessed by a City Engineer knowledgeable of the needs and priorities of the
City and could additionally be leveraged by a CIP list. Additionally, the City
representatives were able to present the single case to the City Council for quick approval.
This example may be replicated in other similar cities, i.e., where potential public GSI
retrofit is known and/or can be quickly assessed, City priorities are well established,
redevelopment areas are delineated, and decision-makers can come to agreement on a
single project quickly. For more complex cities, it is recommended that consideration of
future projects be conducted (minimally) before a single implementation of alternative
compliance without the prior development of a more comprehensive alternative
compliance program. Any alternative compliance that is approved by the City is likely to
set the precedent for subsequent alternative compliance agreements. Suggested
considerations and steps to take for development of an alternative compliance program
are provided in sections 4 and 5.
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3.2.2 City of San Diego, California
The City of San Diego Alternative Compliance Program consists of two phases, the
second of which is under development. Phase 1 of the program is similar to Option 1 of
the MRP (LID Treatment at an Offsite Location). This Phase allows Priority
Development/Redevelopment Projects (PDPs) to satisfy their pollutant control and
hydromodification control requirements by implementing stormwater BMPs at an offsite
location within the same watershed. Phase 1 is referred to as “applicant implemented”
alternative compliance because project applicants/owners are responsible for all aspects
of the offsite alternative compliance project, including land acquisition, design and
construction, and long-term operation and maintenance of the offsite BMP. Offsite
alternative compliance projects must demonstrate that they provide a greater overall water
quality benefit through application of the procedures and formulas included in the Water
Quality Equivalency Guidance Document (County of San Diego, 2015), a regional
guidance document developed by the San Diego co-permittees and approved by the
Region 9 Water Quality Control Board (Region 9; as required by the 2013 San Diego
Regional MS4 Permit).
The City of San Diego is in the process of expanding its program through development
of a stormwater credit trading program. This program would allow Priority PDPs to
satisfy their pollutant control and hydromodification control requirements by purchasing
credits generated from offsite BMPs. Credits transactions would occur between
generators and buyers and be tracked through an online dashboard. The City of San Diego
program is being led by the Transportation and Storm Water Department. Program
development has also relied heavily upon feedback from the City of San Diego’s
Development Services Department, Public Works Department, City of San Diego
Attorney’s Office, and Planning Department.
The City of San Diego is in the process of initiating a Programmatic environmental impact
report for their Alternative Compliance Program. They are estimating the program will be
launched in early 2021. The City will publish a Program Standards Document, detailing the
rules and requirements governing the program, when the program launches. The Program
Standards are being developed by conducting a review of other trading programs and through an
extensive advisory process, which is used to evaluate program options and incorporate feedback
from local and national subject matter experts. The advisory process has included bi-monthly
meetings open to the public as well as internal City of San Diego workgroup meetings.
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3.2.3 Washington, D.C.
Washington, D.C.’s Department of Energy and Environment (DOEE) requires new
development and redevelopment to install stormwater management facilities that retain a
portion of the runoff generated from the development. DOEE administers a program in
which eligible properties may install green stormwater infrastructure to capture excess
volume (that meets the program’s requirements) to generate stormwater retention credits;
those credits can then be sold to other properties (i.e., developers that need retention
credits) through a credit exchange (the DOEE Stormwater Database). Projects/developers
that cannot meet their full onsite compliance requirements, but do not want to purchase
stormwater credits, have the option to pay an In-Lieu-Fee. The In-Lieu Fee is based on
the most expensive BMP in the most expensive area within the watershed (DOEE, 2018).
3.2.4 Chesapeake Bay (Prince George’s County), Maryland
The Prince George’s County program is a partnership between the County and tax-
exempt faith-based organizations and 501(c)(3) nonprofit organizations to treat and
reduce stormwater runoff in exchange for a reduction in their Clean Water Act Fee (Prince
George’s County, 2018). These organizations may agree to one or all three alternative
compliance options, which include an easement whereby the County will install
stormwater BMPs on the property; an outreach and education campaign that encourages
other property owners to participate in the Rain Check Rebate Program; and/or a
demonstrated commitment to work with certified lawn and landscaping companies or to
conduct good housekeeping practices on their property. This form of alternative
compliance is not the same as the City of San Diego or the Washington D.C. programs,
and requires the existence of a stormwater utility fee.
3.2.5 Lake Tahoe
The Lake Tahoe Lake Clarity Program is a quantitative load reduction program that tracks
pollutant control measures in the Lake Tahoe basin. The regulating agencies for the
program are the Lahontan Regional Water Quality Control Board and the Nevada
Division of Environmental Protection. The program is implemented and documented by
seven local jurisdictions: El Dorado, Placer, Washoe, and Douglas counties; the City of
South Lake Tahoe; California Department of Transportation; and Nevada Department of
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Transportation. The program aims to improve lake clarity by tracking the pollutants that
contribute to lake clarity degradation: fine sediment particles (FSP), nitrogen, and
phosphorus.
To implement the program, the seven jurisdictions can “reward” actions that achieve load
reductions of the target pollutants with credits. The jurisdictions can then implement the
most cost-effective treatment system, by either trading, sharing, or utilizing the
distributed credits. The crediting process requires each jurisdiction to estimate the
expected loads, register expected credits, inspect actual conditions, and declare credits
for each treatment BMP included. The crediting process utilizes four stormwater tracking
tools that are made available to each jurisdiction (Lahontan Water Quality Control Board
and Nevada Division of Environmental Protection, 2015). This program is a crediting
program for permit accounting, so also has a different structure than the other alternative
compliance programs described above.
3.2.6 San Francisco Public Utilities Commission
The San Francisco Public Utilities Commission (SFPUC) is in the process of developing
an alternative compliance and In-Lieu Fee programs for their Stormwater Management
Requirements. The program will be released to the public when it is completed.
4. DEVELOPING AN ALTERNATIVE COMPLIANCE PROGRAM
4.1 Initial Considerations
While alternative compliance programs may provide additional flexibility and
efficiencies for Permittees, there are also costs associated with program development and
implementation. Additionally, the type of alternative compliance allowed through the
program, and the rules and conditions associated with compliance, will have a direct
impact on participation rates and program costs. For these reasons, it is important to
evaluate certain initial conditions before establishing a program. These may include the
following conditions. Some of these conditions may not apply to smaller cities or cities
where minimal new or re- development is anticipated.
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1. Equivalency and Net Environmental Benefit
a. What equations, metrics, and models can be used to demonstrate treatment
of an “equivalent quantity of both stormwater runoff and pollutant
loading” and achievement of a “net environmental benefit” as required by
the MRP?
2. Administrating Department(s)
a. Which City department will manage the program? Any alternative
compliance program will require the review and approval of additional
plans and submittals. Offsite mitigation also requires annual reporting,
tracking, and enforcement. Which City department(s) are best equipped to
assume these responsibilities, and how will the City coordinate additional
efforts?
3. Total Costs and Funding Mechanisms
a. How will the cost of program administration be distributed and where will
additional funds come from?
b. Does the managing department have the budget/staff needed to expand its
current responsibilities?
c. Can costs be recovered with normal plan review fees, or are additional
fees warranted that are specific to alternative compliance projects?
d. For In-Lieu Fee compliance, how will the fee be set and how will ongoing
operation and maintenance be funded?
4. Liability Concerns (If Insufficient Applicants for In-Lieu Fee Program)
a. If the City plans construction of a regional BMP and collects In-Lieu Fees
that cover only a portion of the BMP cost, how will the additional cost be
covered? Furthermore, if a regional BMP fails after construction, what
funding sources are there for rehabilitation/replacement?
b. If construction of the regional BMP is delayed beyond the allowable three-
year (or extended five-year) window due to unforeseeable circumstances,
is the City liable for unmitigated water quality impacts?
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5. Configuration and Responsible Party for Tracking System
a. How will offsite mitigation be tracked and what will the configuration of
the tracking and reporting mechanism be? For example, DOEE manages
a Stormwater Database that tracks available and purchased credits or
internal Access Databases or Spreadsheets.
b. Who would manage the In-Lieu Fee program, and how would it be
tracked? How would fees paid into the program be managed over time
(e.g., if it takes five years to build a project)?
6. Application and Approval Process
a. Who will be allowed to participate in the program and how will
participating applicants be identified and approved?
b. Can existing submittals and templates be amended to include alternative
compliance sections or provisions, or do new templates need to be
developed?
c. Similarly, can existing review and approval processes be amended to
include alternative compliance, and at what stage of project
submittal/approval can alternative compliance be used?
7. Reporting
a. How will the City include alternative compliance projects into its annual
report?
b. Will self-reporting of offsite mitigation projects be sufficient, or will the
City require internal or third-party inspection/review of projects annually?
8. Interest from and Coordination with Cooperating Parties (i.e., Developers)
a. How could the combination of offsite mitigation project and program
costs, additional planning and engineering, onsite technical feasibility, and
development/redevelopment patterns and rates impact program
participation rates?
b. If LID treatment at an offsite location is the only alternative compliance
options available, will participation rates be high enough to justify
additional program costs?
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c. Who will provide outreach to developers? How often will trainings/
workshops be provided?
4.2 Potential Studies Needed
Several studies, meetings, workgroups, and/or other coordination may be needed prior to
initiating program development to answer the questions posed in section 4.1 and establish
the program framework. Identifying the potential to implement C.3.e. can be examined
through a series of feasibility/interest studies, including:
1. Is treatment at an offsite location feasible for developers?
a. Space – Feasibility study to identify potential opportunities for offsite
treatment within the same watershed for known C.3. projects (should those
projects choose to move forward with alternative compliance).
b. Cost – Analysis to determine if the cost of developing opportunities for
offsite treatment would be financially feasible.
c. Interest – Is there interest in development community for an alternative
compliance program or an In-Lieu Fee program? Suggest sending a survey
to developers to identify interest in use of program.
2. Is alternative compliance program feasible for City?
a. Cost – What is the administrative cost for the City to implement a program
to track alternative compliance? How many projects would need to
participate for financial feasibility?
b. Tracking/Review – Study to develop a tracking and review methodology
or system, including identifying who/what department would be
responsible for tracking projects and who/what department would be
responsible for reviewing and approving projects.
3. Is an In-Lieu Fee program feasible for the City?
a. Regional projects – Feasibility study to identify whether sufficient
potential opportunities for Regional Projects exist to mitigate the
development that is likely to trigger C.3.
b. Cost – Analyses to estimate how much identified Regional Projects would
cost, and how many development projects would have to contribute In-
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Lieu Fees to cover those costs, including the administrative and full
lifecycle costs must be covered by the fee.
c. Potential for Liability – If the City designates specific Regional Projects
for In-Lieu Fees, and not as many developers as expected pay the In-Lieu
Fee, how will the costs be covered to ensure that those developers that
have paid the In-Lieu Fee are in compliance (i.e., that the Regional
Project(s) still gets built)?
4. How will treatment equivalency be established?
a. Study to identify what mechanism(s) will be used to equate offsite water
quality improvements with onsite improvements. Any alternative
compliance program is founded upon an established equivalency between
onsite and offsite projects. Offsite projects must demonstrate that they are
able to provide an equal or greater water quality benefit to the control that
would have been built onsite. Establishing equivalency requires the
consideration of expected pollutant loads at both the onsite and offsite
location (i.e., land use differences in the tributary areas), volume treated
by the BMP, and BMP removal efficiencies. The Water Quality
Equivalency Guidance Document for Region 9 developed by the San
Diego regional Co-permittees provides one example (County of San Diego,
2015).
4.3 Steps Needed to Develop a Program
Suggested steps to develop a program include (adapted from the In-Lieu Fee Guidance
document and other sources):
1. Form a team within the City that is responsible for program development. This
may include a representative from the County or neighboring cities, who will help
decide if a watershed-based program (which extends across City boundaries) is
desired.
2. As a team, identify the feasibility studies that are needed (see questions posed in
section 4.1 and suggested studies in section 4.2) and determine a budget to
perform the studies. Arrange for the studies to occur in-house and/or through an
outside consultant or other party.
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3. Review the results of the feasibility studies and use the results to determine the
degree to which the City could implement an alternative compliance and/or In-
Lieu Fee program.
4. Develop a policy or ordinance based on the findings and program determination
(see section 5). Identify (as part of policy or separately) a method for “adaptive
management” (i.e., altering the program based on findings from program
operation).
5. Identify who is responsible for tracking and reporting; set up a system to automate
or simplify tracking. This should include a method for financial tracking and
accounting, as well as considerations of units of measurement for compliance and
equivalency reporting.
6. Develop a guidance manual and outreach program for developers interested in
alternative compliance and/or an In-Lieu Fee.
7. Submit program documents to the Regional Water Quality Control Board for
review and approval.
8. Launch program.
9. Complete annual reporting and make programmatic changes through adaptive
management mechanisms established during program development.
5. POLICY OR ORDINANCE OVERVIEW
Language about offsite alternative compliance could be added to a broader stormwater
management ordinance, or it could be developed for a standalone ordinance pertaining
only to offsite alternative compliance. A City-specific offsite alternative compliance
ordinance would include the following elements:
1. Applicant Requirements – These include, but are not limited to, minimum onsite
stormwater requirements for projects using alternative compliance, application
details, and eligibility requirements.
2. Offsite Mitigation Project Requirements – These include, but are not limited to,
project location, priority watershed location requirements/considerations, land
rights and easement information, maintenance agreements, documentation
requirements, and construction requirements.
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3. City or Water Authority Requirements – These include, but are not limited to,
inspection specifications, rights, and frequencies, construction
authorization/approval, and authority to conduct construction inspections.
4. In-Lieu Fee requirements – Information on whether a payment-in-lieu option is
available to applicants, and if so, how the rate will be calculated, collected, and
tracked.
5.1 Existing Policies and Ordinances
5.1.1 Washington, D.C.
DOEE adopted the 2013 Stormwater Management Rule, an amendment to Chapter 5
(Water Quality and Pollution) of Title 21 (Water and Sanitation) of the District of
Columbia Municipal Regulations (DCMR). The amendment provides regulated sites with
an option to meet a portion of their stormwater management compliance requirements
with offsite retention by using Stormwater Retention Credits or paying an In-Lieu Fee to
DOEE.
5.1.2 West Virginia
The Center for Watershed Protection developed Guidance for Developing an Off-Site
Stormwater Compliance Program in West Virginia in 2012 (West Virginia Department
of Environmental Protection, 2012). The document includes “Appendix B: Model
Ordinance for Off-Site Compliance,” which includes language that covers the four
elements outlined above in the draft ordinance summary.
5.1.3 Central Coast, California
Central Coast Low Impact Development Initiative (LIDI), which is endowed by the
Central Coast Regional Water Quality Control Board and the Bay Foundation of Morro
Bay, supports “the vision of healthy watersheds through the implementation of LID
design principles…throughout the Central Coast Region.” LIDI developed the Central
Coast Draft Municipal Alternative Compliance Model Ordinance (2014), a draft
ordinance for jurisdictions that want to establish an alternative compliance program. This
document draws on concepts and language provided in the West Virginia Model
Ordinance.
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City of Dublin Alternative Compliance Handbook
16
5.1.4 USEPA
The USEPA published the Model Post-Construction Stormwater Runoff Control
Ordinance in 2015 to assistant communities with creating their own stormwater
management ordinances (USEPA, 2015). The model ordinance includes high-level
language about offsite facilities and In-Lieu Fees for stormwater management practices.
6. COSTS
The costs associated with developing, implementing, and managing an alternative
compliance program vary considerably based on the following factors:
1. The availability of existing program elements (i.e., equivalency
methods/guidance and ordinances/policies).
2. The type of offsite compliance allowed through the program (i.e., applicant
implemented, In-Lieu Fee, and/or credit trading).
3. The size/extent of the program and expected level of participation.
The cost of establishing the most basic alternative compliance options (applicant
implemented) can range from tens of thousands of dollars to hundreds of thousands of
dollars, with the lower end of the cost spectrum representing programs that already have
established equivalency and policy/ordinance components (or, minimally, simple
frameworks).
The cost of establishing In-Lieu Fee programs can be significantly greater than that of
developing a simple applicant implemented program due to the required fee studies and
legal/program assurance mechanisms. Developing these programs can cost hundreds of
thousands of dollars.
The cost of establishing a Credit Trading Program can be similar or greater than the cost
of establishing an In-Lieu Fee program. This cost varies greatly based on the type of credit
trading allowed (single or multiple types of credits), the size of the trading areas (local
jurisdiction and watershed based or cross-jurisdictional), the role of the municipality in
program administration, and the type of credit market established, among other
considerations. Costs of establishing a Credit Trading Program can range from hundreds
of thousands of dollars to millions of dollars.
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City of Dublin Alternative Compliance Handbook
17
7. RECOMMENDED NEXT STEPS
Given the summary/information above, next steps recommended for the City of Dublin
are provided. These dates are intended as a guide; they may differ depending on the
number of studies identified, the extent of administrative discussions, and the resources
available to complete the recommended actions.
Timeline Recommended Action
Year 1
1. Identify Alternative Compliance Team
2. Identify and Initiate Feasibility Studies
Year 2
3. Complete Feasibility Studies and Review Results
4. Determine Type and Extent of Program and Develop Policy or
Ordinance
Year 3
5. Identify Technical and Financial Tracking Procedures
6. Author Guidance Manual and Develop Outreach Program
7. Submit Documents to the Regional Water Quality Control
Board for Review and Approval
Year 4 +
8. Launch Program
9. Prepare Annual Reports and Adaptively Manage Program
8. REFERENCES
Central Coast Low Impact Development Initiative (LIDI), 2014. Draft Municipal
Alternative Compliance Model Ordinance. 4 April. Retrieved 9 May 2018.
Available from https://storage.googleapis.com/centralcoastlidi-
org/uploads/Model Alt_Compliance_Ordinance.pdf
City of Emeryville, 2017. Resolution Of The City Council Of The City Of Emeryville
Authorizing The City Manager To Enter Into The Public Market Off-Site
Stormwater Improvement Agreement With AC-CCRP PUBLIC MARKET, L.P. To
Construct Off-Site Low Impact Development Stormwater Treatment Measures On
Public Right-Of-Way And Public Open Space As An Alternative Method Of
Compliance With The Requirements Of The Municipal Regional Stormwater
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City of Dublin Alternative Compliance Handbook
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National Pollutant Discharge Elimination System (NPDES) Permit For The
Redevelopment Of The Emeryville Marketplace, And Accept $154,000 As A One-
Time Lump Sum Payment To The City For The On-Going Long Term
Maintenance Of Said Stormwater Treatment Measures. Memorandum to Carolyn
Lehr, City Manager. 20 June.
County of San Diego, 2015. Water Quality Equivalency Guidance Document for Region
9. Available from https://www.projectcleanwater.org/water-quality-equivalency-
guidance/
District of Columbia Department of Energy and Environment (DOEE), 2018. Stormwater
Retention Credit Trading Program. Retrieved May 2018. Available from
https://doee.dc.gov/src
Lahontan Water Quality Control Board and Nevada Division of Environmental
Protection, 2015. Lake Clarity Crediting Program Handbook: for Lake Tahoe
TMDL Implementation v2.0. Prepared by Environmental Incentives, LLC.
Lotus Water, 2018. E-mail communication with E. Zickler. 30 April.
Prince George’s County, 2018. Alternative Compliance. Retrieved April 2018. Available
from https://www.princegeorgescountymd.gov/311/Alternative-Compliance
United States Environmental Protection Agency (USEPA), 2007. Water Quality Trading
Toolkit for Permit Writers. Updated 2009. Available from
https://www.epa.gov/npdes/water-quality-trading-toolkit-permit-writers
USEPA, 2015. Model Post-Construction Stormwater Runoff Control Ordinance.
Retrieved 9 May 2018. Available from
https://www.epa.gov/sites/production/files/2015-
12/documents/modelillicit_0.pdf
West Virginia Department of Environmental Protection, 2012. Guidance for Developing
an Off-Site Stormwater Compliance Program in West Virginia. December.
Retrieved 9 May 2018. Available from
http://dep.wv.gov/WWE/Programs/stormwater/MS4/permits/Documents/WV_M
itigation-FeeInLieu-Guidance_Final_Jan-2013.pdf
107DRAFTAppendix H City of Dublin Green Stormwater Infrastructure Plan
Prepared for
City of Dublin
100 Civic Plaza
Dublin, California 94568
PUBLIC-PRIVATE-PARTNERSHIPS
(PERFORMANCE-BASED
INFRASTRUCTURE) FOR STORMWATER
AND MS4 PERMIT COMPLIANCE
WHITE PAPER
Prepared by
1111 Broadway, 6th Floor
Oakland, California 94607
Project Number: WW2298
June 2019
108 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix H
P3 White Paper_120617 ii
TABLE OF CONTENTS
1. INTRODUCTION/OVERVIEW .......................................................................... 1
1.1 Typical P3 Structures ................................................................................... 2
2. EXAMPLES OF STORMWATER P3 IMPLEMENTATION ............................ 4
2.1 Prince Georges County, MD – Community-Based P3 ................................ 4
2.2 Mill Creek Wetlands .................................................................................... 6
3. INITIAL STEPS FOR P3 PROGRAM DEVELOPMENT .................................. 8
3.1 Demonstration Project ................................................................................. 8
3.2 Request for Information (or Expressions of Interest) .................................. 8
3.3 Workshop ..................................................................................................... 9
4. POTENTIAL REVENUE AND FUNDING SOURCES ..................................... 9
4.1 California Government Code 5956 .............................................................. 9
4.2 SB 231 (Hertzberg) ...................................................................................... 9
4.3 Keys to Successful Implementation of P3s ............................................... 10
5. SUMMARY ........................................................................................................ 11
6. REFERENCES ................................................................................................... 11
White paper developed by Ken Susilo, Senior Principal, and Kelly Havens, Senior
Engineer, Geosyntec Consultants.
109DRAFTAppendix H City of Dublin Green Stormwater Infrastructure Plan
3
1. INTRODUCTION/OVERVIEW
The City of Dublin (City) is investigating Public-Private-Partnerships (P3s) as a potential
implementation approach toward attaining Municipal Regional Permit (MRP) compliance. This
white paper was developed to provide an overview of P3s for stormwater.
P3s are performance-based business ventures, funded and operated through partnerships by and
between government and the private sector. There have been inconsistent levels of performance
and success in some industries (e.g., with transportation P3s), which has made some decision-
makers wary of P3 applications. As such, and particularly in the stormwater context, P3s may be
better (and equally accurately) described as Performance-Based Infrastructure (PBI), where the
focus is on the alignment of design. Construction, operations and maintenance are key concepts,
with the ultimate focus on meeting project objectives. Stormwater P3s are intended to help
communities optimize limited labor resources, meet compliance obligations, and control risk and
finances to help build and maintain public infrastructure.
As previously noted, P3s (while relatively new for stormwater applications) have resulted in the
design, construction, and maintenance of many types of major public infrastructure across the
United States, Canada, and globally. Benefits of P3 implementation can include the development
of multi-objective, multi- benefit projects that fill multiple needs, resulting in lower agency-
specific costs. An example of this is where multiple agencies, such as stormwater agencies, public
works departments, water departments, and/or parks departments can cost-share as there are
shared, multiple benefits of green stormwater infrastructure implementation. P3s can significantly
decrease administrative complexity and increase the speed of implementation by streamlining the
procurement and financing portions of projects. In the stormwater context, P3s could demonstrate
(to regulators, third parties, and the public) proactive action toward Municipal Separate Storm
Sewer (MS4) permit compliance, while sharing some of the permit-associated risk (schedule and
regulatory compliance, financial, performance, etc.). When properly executed, true value can
be realized by utilizing innovation and leading-edge tools (such as real-time forecasting and
controls) and regulatory options (such as alternative compliance approaches), while focusing on
outcomes as performance-based metrics.
1.1 Typical P3 Structures
P3s have been implemented through multiple program structures. One common structure is Design-
Build-Finance-Operate-Maintain (DBFOM). After project needs, performance metrics, and long-
term obligations are established (and preliminary studies conducted), the DBFOM structure entails
that the P3 Developer (or Concessionaire) produces the final design and constructs the project or
projects. Unless there are significant cash reserves or significant and available bonding capacity
available to the public sponsor or owner (i.e., the permittee), the P3 Developer would arrange for
financing of up-front costs. For projects with more complex performance metrics, the P3 Developer
110 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix H
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has the option to conduct initial monitoring and optimization studies and implement adaptive
management, in order to confirm the project performs as expected or better. Then, long-term
facility performance preservation actions (and or including operations and maintenance in
compliance with applicable requirements) are conducted for the life of the project. Ultimately, after
both performance and financial obligations are met, the P3-developed assets are returned to the
owning public agency.
An example of the P3 relationships that may be involved in a DBFOM or similar P3 program
structure is provided in Figure 1.
Figure 1: P3 Structures and Relationships (Susilo, 2017)
A more detailed demonstration of the functional roles and relationships between the public owner,
outside parties, and various members of the implementation team in a typical DBFOM P3 structure
is shown in Figure 2. Of note is the significant potential obligation and risk taken by the P3
Developer in this process, as they are largely responsible for the majority of the implementation
tasks. While this risk transfer presents a significant benefit to the public owner (i.e., permittee),
the risks must be quantified and monetized and included in the delivery cost to adequately
incentivize P3 Developers.
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Figure 2: Functional Roles for Parties Involved in Typical P3 Structure (Adapted
from Susilo, 2017)
2. EXAMPLES OF STORMWATER P3 IMPLEMENTATION
Examples of implementation of full stormwater P3s are scarce. Two examples are
provided from the Mid-Atlantic region and Southern California in the following sections;
it should be recognized, however, that neither example is fully analogous to the
stormwater P3s described in other sections of this white paper.
2.1 Prince Georges County, MD – Community-Based P3
The first stormwater P3 in the nation is currently being implemented at Prince Georges
County (PGC), Maryland, and was initiated in 2015. This program, led by Corvias
Solutions and the Clean Water Partnership, is unique in that it is a Community-Based P3
(CBP3), which incorporates a substantial community engagement and jobs component. It
also does not require the P3 Developer to provide financing (thus would not be
112 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix H
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considered a full DBFOM). One potential factor in the program’s success is that
compliance with the Chesapeake Bay total maximum daily load (TMDL) is quite straight-
forward when compared to California TMDLs and MS4 Permit requirements (i.e., it is
more like implementation of new development requirements than meeting California
MS4 end-of-pipe and receiving water monitoring objectives).
Initial program objectives were to retrofit 2,000 impervious acres (the compliance unit of
measure for the Chesapeake Bay TMDLs) with green stormwater infrastructure, with the
flexibility to potentially expand to 15,000 acres by 2025. The CBP3 required support and
leadership from the County Executive, Legislative Branch, and Department of the
Environment and Department of Central Services.
In 2016, the first full construction season resulted in the completion of 24 projects and
the retrofit of 349 acres to meet the regulatory compliance requirements. To meet social
and economic goals (particularly utilization of local, small, and minority businesses),
programs such as a mentor-protégé program and a collaboration with the public schools
were implemented as key milestones. By mid-2017, the program had completed 38
retrofit projects encompassing 690 total impervious acres. Over 2,100 acres have been
retrofitted to date (through March 2019).
Figure 3: Information Regarding the PGC CBP3 is available online (Clean Water
Partnership)
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2.2 Mill Creek Wetlands
Mill Creek Wetlands was a $17 million P3 developed in the Inland Empire (Riverside
and San Bernardino Counties), California. The project was developed as a partnership
between the City of Ontario, Lewis Operating Group (Lewis), United States Army Corps
of Engineers, State Water Resources Control Board, and the Santa Ana Regional Water
Quality Control Board (who provided grant funding). Other participating agencies
included the County of San Bernardino and City of Chino, where the project was located.
Lewis led the project design and engineering and worked with the City of Ontario (project
public owner) on permit negotiations, environmental clearance, and funding acquisition
efforts. The public agencies involved are responsible for long-term operations and
maintenance.
The project treated dry weather flows and “first-flush” stormwater from an approximate
77-square-mile drainage area through a 140-acre-foot (45-acre) constructed wetland
system, located in the Prado Dam basin (and 500-year flood inundation limit). The project
diverts water from Cucamonga Channel/Mill Creek, and partially mitigates the
stormwater runoff from an upstream 3,000-acre development. Public benefits were
calculated to be approximately three times the conventional approach. The approach is
also very similar to the Alternative Compliance methods currently being explored in
Southern California (e.g., San Diego County).
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Figure 4: The Mill Creek Wetlands P3 Project (Susilo, 2014)
115DRAFTAppendix H City of Dublin Green Stormwater Infrastructure Plan
9
3. INITIAL STEPS FOR P3 PROGRAM DEVELOPMENT
The following describes a few potential initial next steps toward exploring the
feasibility of P3s for stormwater in the City.
3.1 Demonstration Project
As P3 implementation has not been well established in California for current MS4 Permit
(and TMDL) compliance, a demonstration or pilot-scale implementation could be the first
step toward assessing the efficacy of the process. For this demonstration, performance
metrics consistent with permit requirements would need to be drafted, confirmed with the
Alameda Countywide Clean Water Program and the San Francisco Regional Water
Quality Control Board, and established by the City. Because establishment of a reliable
funding stream is critical for full-scale implementation, an initial allocation of resources
would be needed for demonstration purposes. The political, procedural, legal, regulatory,
financial, and technical details developed as part of a demonstration project could confirm
whether P3 implementation is feasible. Additionally, if the intent of the process is to target
social and economic benefits, a demonstration project could provide foundational
evidence to justify more sustainable funding streams.
3.2 Request for Information (or Expressions of Interest)
As part of either a demonstration project or full-scale program implementation, a request
for information (RFI) or request for expressions of interest (RFEI) could be issued by the
City. Objectives of this approach would be to:
• Determine concessionaire and attorney perspectives on funding and financing
options, risk transfer potential, performance metrics (performance-based
infrastructure), monitoring, portfolio needs, etc.;
• Develop potential mutually beneficial framework and governance structures,
duration of potential agreements;
• Identify potential range of contract values and scopes;
• Explore possible technology applications (asset management, real time controls);
and
• Confirm the roles and responsibilities (and any risk transfer) for the City.
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3.3 Workshop
A third (or potentially, first) implementation activity could be the conducting of a
workshop with elected officials, directors, and policy leaders to explore options and
ultimate objectives. This could provide foundational elements for a pilot demonstration
and/or RFI/RFEI.
4. POTENTIAL REVENUE AND FUNDING SOURCES
4.1 California Government Code 5956
California Government Code 5956 states the following conditions, including the
provision that infrastructure produce fees, for P3s in California:
The ability of local government to fund necessary infrastructure improvements is
limited by funding constraints. If local governmental agencies are going to
maintain the quality of life that this infrastructure provides, they must find new
funding sources. One source of new money is private sector investment capital
utilized to design, construct, rebuild, repair, operate and maintain infrastructure
facilities. Unless private sector investment capital becomes available to study,
plan, design, construct, develop, finance, rebuild, repair, or operate and
maintain, or any combination thereof, fee-producing infrastructure facilities,
some local governmental agencies will be unable to replace deteriorating
infrastructure. Further, some local governmental agencies will be unable to
expand and build new infrastructure facilities to serve increasing population.
As such, ultimately a stormwater fee or utility will be likely be critical for
implementation.
4.2 SB 231 (Hertzberg)
Proposition 218 exempts “sewer” fees and taxes from its provisions. Court decisions have
interpreted the meaning of “sewer” to preclude “stormwater” within its definition. As a
result, counties and municipalities have been reluctant to go to the voters with tax
proposals to support stormwater capture and urban runoff programs and projects to
117DRAFTAppendix H City of Dublin Green Stormwater Infrastructure Plan
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comply with MS4 requirements. Some (Contra Costa County1) have tried and failed.
Some (Culver City) have succeeded. The Culver City approach included a “bottom-up”
approach to establishing fee amounts (Culver City, 2017). An illustration of a “top-down”
fee study, conducted to address current MS4/TMDL compliance obligation, was
completed in San Diego in 2016 (City of San Diego, 2016).
SB 231 simply defines “sewer” to include “stormwater” in such a way as to exempt
stormwater fees and taxes from its provisions. The intent of the change is to provide
guidance to the courts in their interpretation of “sewer” in the context of Proposition 218.
It is anticipated (by Senator Hertzberg and others) that any city or county taking
advantage of the provisions of SB 231 by adopting a stormwater fee or tax without
complying with the election provisions of Proposition 218 will be challenged in court by
the Howard Jarvis Taxpayers Association. Senator Hertzberg has indicated that thereis a
jurisdiction willing to serve as a “test case” and that he and attorney Michael Colantuono
are encouraging SB 231 supporters to join in the anticipated litigation. According to
Senator Hertzberg, the California League of Cities, County Supervisors Association, the
Association of California Water Agencies, and California Coast Keeper would support
the test case. The legislation became effective on 1 January 2018, but action by the “test
case” jurisdiction has not yet occurred (Hertzberg, 2017 and Monterey Regional Storm
Water Management Program [MRSWMP], 2017).
4.3 Keys to Successful Implementation of P3s
The following are a few elements that will likely be key to successful implementation of
P3s:
• If not managed by a single entity (e.g., a department within the City of Dublin),
an adequately flexible governance structure (e.g., Joint Powers Authority, Tax
Exempt Public-Benefit [63-20] Corporation, Property-Assessed Clean Energy
model, etc.) will be needed;
• Political willingness and support by elected officials;
• Highly qualified and willing partners, both on the owner and P3 Developer side;
1 See article from The Mercury News, 2012.
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• Identifiable revenue sources (through a fee or utility);
• Specific technical elements that would likely include:
o Asset “optimization” (but multiple variables, not just cost);
o Adaptive asset management (open/flexible platforms);
o Operations and maintenance of best management practices (BMPs) over
project life; and
o New technologies (such as real-time controllers and project dashboards).
5. SUMMARY
P3s and PBIs are potentially viable options for stormwater agencies faced with aggressive
implementation schedules and onerous permit requirements. While there are many
potential benefits to this approach, past experience with other types of P3s highlights the
need for a thoughtful and well-vetted approach to establishing metrics, as well as
maintaining quality and long-term sustainability. In addition, political support and long-
term funding would be essential to a viable California P3 program. The exploration or
development of these elements are potential next steps in the evaluation of P3s as an
implementation solution.
6. REFERENCES
City of San Diego, 2016. City of San Diego Storm Water Fee Study. September.
https://www.sandiego.gov/sites/default/files/csd_stormwaterfeestudy_submissio
n.pdf.
Clean Water Partnership, 2017. https://thecleanwaterpartnership.com.
Culver City, 2017. Measure CW. Available at http://www.culvercity.org/city-
hall/information/election-information/ballot-measure-information/clean-culver-
city.
Hertzberg, 2017. Webinar: Getting it right: Stormwater Stewardship. Available at
http://sd18.senate.ca.gov/sb231-webinar.
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Monterey Regional Storm Water Management Program (MRSWMP), 2017. Notice and
Agenda, Management Committee for the Monterey Regional Storm Water
Management Program (MRSWMP). 25 October. Available at
http://montereysea.org/wp-content/uploads/2017/10/MRSWMP-MC-Agenda-
10-25-17-2.pdf.
Reader and Vorderbrueggen, 2012. Contra Costa water fee defeated. The Mercury News.
7 May. Available at http://www.mercurynews.com/2012/05/07/contra-costa-
water-fee-defeated/.
Susilo, K., 2014. Mill Creek Wetlands: A Demonstration of Regional Project Benefits,
Public-Private Partnerships, and Water Quality Improvement in Southern
California. CASQA Annual Conference, Orange County, California.
Susilo, K., 2017. Performance Based Infrastructure and Public Private Partnership (P3)
Solutions for Water Resources and Stormwater Quality, City and County
Engineers Association, Monterey Park.
United States Fish and Wildlife Service (FWS), 2009. Conservation Banking: Incentives
for Stewardship. July. https://www.fws.gov/sacramento/es/Conservation-
Banking/Home/Documents/conservation_banking.pdf.
120 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix HCity of Dublin ‐ Applicable Grant Funding Sources Prepared by Geosyntec ConsultantsProgram/ Grant NameAgency or SourceDescriptionMulti‐Benefit PossibilitiesCurrent Funding LevelAnticipated Rigor (Low, Moderate, High)Clean Water State Revolving Fund Program (CWSRF)California Environmental Protection Agency ‐State Water Resources Control Board (SWRCB)The Clean Water State Revolving Fund (CWSRF) program offers low cost financing for a wide variety of water quality projects. The program has significant financial assets, and is capable of financing projects from <$1 million to >$100 million.Multi‐benefits identified include: wastewater treatment and water recycling; point and non‐point source stormwater flow control and treatment; aquatic health improvements; climate resilient and sustainable water resources. The primary scoring concerns five Resources/Impacts: Drinking Water Source; Delta Water Quality; Water Recycling; Impaired Water Body; Water Quality Control Plan or Permit. For any/all of these, the project Purpose is categorized as: Corrective, Preventive, or Improvement. Secondary scoring includes points for: multi‐benefits; adoption of a climate change action plan/policy; project is cited in multi‐agency regional environmental management plan, increases local drinking water supply, or has multi‐media environmental benefits; fund matching. Annual average is $500,000,000Moderate rigorStormwater Grant Program (SWGP)California Environmental Protection Agency ‐State Water Resources Control Board (SWRCB)Part of Proposition 1 (AB 1471); Round 2 focus on Implementation.Multi‐benefits identified include: green infrastructure; stormwater capture and treatment facilities. Purpose of project to improve water quality and/or adapt water infrastructure to climate change. It should be noted that project must be included as part of a Storm Water Resource Plan, or functional equivalent, to be eligible for grant funds.$90 MillionLow rigor, given lead time; recommended for an applicable project.Groundwater Grant Program (GWGP)California Environmental Protection Agency ‐State Water Resources Control Board (SWRCB)Part of Proposition 1 (AB 1471, Chapter 10); in Round 2; for groundwater that serves, or has served, as a source of drinking water.The Program Guidelines include multi‐benefits as one of the preferences when assessing an application. To be considered multi‐benefit, the project must be designed to address any/all of the following: more than one Proposition 1 prioritization criteria (manage/mitigate contaminated groundwater; enhance local water supply; maximize recharge opportunities); more than one California Water Action Plan objective (prevent spread, or accelerate cleanup, of contamination in current or former drinking water aquifer; protect drinking water aquifer; provide clean drinking water to DACs or EDAs); or is an integrated part of a groundwater recharge program.$800 Million total (not certain of available funds for Round 2)Moderate rigor, though award for GI may be challenging. Valuable resources available on website.California Infrastructure State Revolving Fund (ISRF); LoanCalifornia Infrastructure and Economic Development Bank (IBank)The ISRF Program provides financing to public agencies and non‐profit corporations sponsored by public agencies for a wide variety of infrastructure and economic development projects (excluding housing).Multi‐benefits are not specifically a criteria, though various types of infrastructure projects are eligible. Amongst those, the following types may be most applicable: city streets; county highways; drainage, water supply, and flood control; environmental mitigation measures; public transit; state highways.Funding level ranges: $50,000 to $25,000,000Probably low rigor, though it is a loan program.Page 1
121DRAFTAppendix H City of Dublin Green Stormwater Infrastructure PlanCity of Dublin ‐ Applicable Grant Funding Sources Prepared by Geosyntec ConsultantsProgram/ Grant NameAgency or SourceDescriptionMulti‐Benefit PossibilitiesCurrent Funding LevelAnticipated Rigor (Low, Moderate, High)Bullitt Foundation: GrantBullitt FoundationThe Bullitt Foundation focuses on infrastructure design that optimizes efficiencies among land use, transportation, energy, water, and waste systems; operates at a cost effective scale; enhances natural systems; reduces carbon emissions; and stores carbon. It advances green infrastructure alternatives to grey infrastructure. The Foundation also seeks to develop conservation finance mechanisms, metrics, and other needed tools to encourage protection and restoration of ecosystem service values related to urban, agricultural, forest, and open space lands. The Foundation funds 501(c)(3) nonprofit organizations, Municipal Corporations, Public Agencies, and Tribal Governments.The multi‐benefit approach is embraced in the "Resilient Cities, Healthy Communities" program (http://www.bullitt.org/programs/resilient‐cities‐healthy‐communities/). As part of the Sustainable Infrastructure component, multi‐benefits include: Advance decentralized, biomimetic, and environmentally resilient systems; Prioritize health and well‐being of humans and nature by promoting walking, biking, and public transportation; Promote systems and cultures in which physical activity is viewed as a benefit; Encourage green infrastructure design that optimizes efficiencies among land use, transportation, energy, water, and waste systems, operates at scale, enhances natural systems, reduces CO2 emissions, and stores carbon.Previous grants range from $10,000‐$120,000.Unknown, potentially challenging to be awarded.Five Star and Urban Waters Restoration Grant ProgramNational Fish and Wildlife FoundationThe Five Star and Urban Waters Restoration Program seeks to develop nation‐wide‐community stewardship of local natural resources, preserving these resources for future generations and enhancing habitat for local wildlife. Projects seek to address water quality issues in priority watersheds, such as erosion due to unstable streambanks, pollution from stormwater runoff, and degraded shorelines caused by development.Multi‐benefits include: wetland, riparian, forest and coastal habitat restoration; wildlife conservation, community tree canopy enhancement, water quality monitoring and green infrastructure best management practices for managing run‐off; increase access to the benefits of nature; reduce the impact of environmental hazards and engage local communities, particularly underserved communities, in project planning, outreach and implementation. From 2018 grantees, there was a range of recipients, with one GI project (https://www.nfwf.org/fivestar/Documents/2018grantslate.pdf; see "Park Forest Green Infrastructure for Stormwater Management (IL)" on page 6).Approximately $2.5 million in 2017. Awards range from $20,000 to $50,000 with an average size of $30,000 and 40‐50 grants awarded per year.Potentially low feasibility of award; focus on urban waters.The Rockefeller Foundation: GrantThe Rockefeller FoundationThe Rockefeller Foundation works to achieve meaningful and measurable impact for poor and vulnerable communities through smart globalization. A portfolio of work structured around core issue areas include: Resilience; Climate Change; Water and Fisheries; Transportation and Infrastructure; Transform Cities; Revalue Ecosystems; and Secure Livelihoods.Multi‐benefits broadly in an urban infrastructure context for climate change resilience (as evidenced by the "100 Resilient Cities" initiative, including Resilient by Design Challenge).The Foundation has awarded grants from under $100,000 to over $2,000,000.Competitive; low probability of acceptance.Page 2
122 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix HCity of Dublin ‐ Applicable Grant Funding Sources Prepared by Geosyntec ConsultantsProgram/ Grant NameAgency or SourceDescriptionMulti‐Benefit PossibilitiesCurrent Funding LevelAnticipated Rigor (Low, Moderate, High)Better Utilizing Investments to Leverage Development (BUILD) Transportation Discretionary Grants programU.S. Department of Transportation (DOT)Better Utilizing Investments to Leverage Development (BUILD) Transportation grants replace the pre‐existing Transportation Investment Generating Economic Recovery (TIGER) grant program. As the Administration looks to enhance America’s infrastructure, FY 2018 BUILD Transportation grants are for investments in surface transportation infrastructure and are to be awarded on a competitive basis for projects that will have a significant local or regional impact. BUILD funding can support roads, bridges, transit, rail, ports or inter‐modal transportation.From the Program website: "The eligibility requirements of BUILD allow project sponsors at the State and local levels to obtain funding for multi‐modal, multi‐jurisdictional projects that are more difficult to support through traditional DOT programs." Further: "The BUILD program enables DOT to use a rigorous merit‐based process to select projects with exceptional benefits, explore ways to deliver projects faster and save on construction costs, and make needed investments in our Nation's infrastructure." Considering the value of transporation assets, having multi‐benefit (flood control, water quality, resiliency) attributes would result in a competitive application. $1.5 billion to be awarded by DOT for the BUILD Transportation program. Maximum grant award is $25,000,000 and no more than $150,000,000 can be awarded to a single State.Moderate rigor; feasible, though competitive.Urban Waters Small Grants (UWSG)U.S. Environmental Protection Agency (EPA)The objective of the Urban Waters Small Grants is to fund projects that will foster a comprehensive understanding of local urban water issues, identify and address these issues at the local level, and educate and empower the community. In particular, the Urban Waters Small Grants seek to help restore and protect urban water quality and revitalize adjacent neighborhoods by engaging communities in activities that increase their connection to, understanding of, and stewardship of local urban waterways.Multi‐benefit priorities: restore urban waters, improve water quality (treatment of urban runoff), community revitalization. From the website: "Improving urban waters requires various levels of government and local stakeholders (e.g., community residents, local businesses, etc.) to work together in developing effective and long‐term solutions with multiple benefits. EPA supports and empowers communities, especially in under‐served areas, who are working on solutions to address multiple community needs and fostering successful collaborative parnterships." The grants are competed and awarded every two years, with individual award amounts of up to $60,000.Competitive; low probability of acceptance.Local Streets and Roads Program California Transportation CommissionSenate Bill 1; administered by CTC.Multi‐benefits are not a driver. The program focus is basic maintenance, rehabilitation, and safety. If a connection can be made to any/all of these, with the added benefit of GI, then may be competitive (consider Complete Streets investments).$1.5 Billion annuallyApplicable. Recommended for an applicable project.Transportation Alternatives; Surface Transportation Block Grant Program (STBG)Federal Highway Administration (FHWA)Authorizes funding for programs and projects defined as transportation alternatives, including on‐ and off‐road pedestrian and bicycle facilities, infrastructure projects for improving non‐driver access to public transportation and enhanced mobility, community improvement activities such as historic preservation and vegetation management, and environmental mitigation related to stormwater and habitat connectivity; recreational trail projects; safe routes to school projects; and projects for planning, designing, or constructing boulevards and other roadways largely in the right‐of‐way of former divided highways.Multi‐benefits not a requirement, but beneficial to strengthen application. Amongst eligible projects are those qualified by 23 USC 328 (environmental restoration and pollution abatement, which includes stormwater treatment). This grant program is measured on "Performance Management", of which includes the natural environment (see Appendix A of the "Transportation Alterantives Program Performance Management Guidebook": https://www.fhwa.dot.gov/environment/transportation_alternatives/performance_management/guidebook/page07.cfm). Note that the Guidebook (can be accessed by working backward through that link) is very useful in framing what is valued as performance for FHWA.Fiscal Year 2019: $11.876 Billion; Fiscal Year 2020: $12.136 BillionApplicable; feasible, though competitivePage 3
123DRAFTAppendix H City of Dublin Green Stormwater Infrastructure PlanCity of Dublin ‐ Applicable Grant Funding Sources Prepared by Geosyntec ConsultantsProgram/ Grant NameAgency or SourceDescriptionMulti‐Benefit PossibilitiesCurrent Funding LevelAnticipated Rigor (Low, Moderate, High)Caltrans Financial Contribution Only (FCO)CaltransGreen infrastructure that would have mutual regulatory benefits for Caltrans and partner.Benefits include: stormwater treatment, TMDL credits, trash load reduction. Multi‐benefits not required for eligibility. Ideally, part of the tributary shed should include Caltrans Right‐of‐Way.funding entered into SHOPP cycleLow rigor, though SHOPP cycle updated every 2 yearsCaltrans Cooperative Implementation Agreement (CIA)CaltransGreen infrastructure that would have mutual regulatory benefits for Caltrans and partner.Benefits include: stormwater treatment, TMDL credits, trash load reduction. Multi‐benefits not required for eligibility. Part of the tributary shed must include Caltrans Right‐of‐Way.funding contingent upon available support excess during Fiscal YearLow rigor, though available funds typically not known until last quarter of Fiscal YearCaltrans Project‐Specific MitigationCaltrans Alternative compliance.Benefits include: stormwater treatment, TMDL credits, trash load reduction. Multi‐benefits not required for eligibility. The alternative compliance must satisfy the mitigation obligation, and be sanctioned by the San Francisco Bay Regional Water Quality Control Board (RWQCB).funding contingent upon mitigation needs Low rigor, though only available when Caltrans capital project needs alternative compliance. Coordination with either Caltrans District 4 or SF Bay RWQCB necessary to determine mitigation needs.Page 4
124 DRAFTCity of Dublin Green Stormwater Infrastructure Plan Appendix H
Appendix I
RESOLUTION XX-19
RESOLUTION NO. xx-19
A RESOLUTION OF THE CITY COUNCIL
OF THE CITY OF DUBLIN
***********
APPROVING THE CITY OF DUBLIN
GREEN STORMWATER INFRASTRUCTURE PLAN
WHEREAS, the San Francisco Bay Regional Water Quality Control Board adopted
the Municipal Regional Stormwater National Pollutant Discharge Elimination System
Permit (MRP) on November 19, 2015 as Order No. R2-2015-0049; and
WHEREAS, the City of Dublin is a permittee under the MRP; and
WHEREAS, per the MRP a Green Stormwater Infrastructure Plan must be adopted
describing how permittees intend to include green stormwater infrastructure (GSI) in
appropriate projects on public and private lands to reduce to the maximum extent
practicable adverse water quality impacts due to urbanization and to meet the Total
Maximum Daily Loads wasteload allocations for mercury and polychlorinated biphenyls;
and
WHEREAS, the GSI Plan is intended to describe how permittees, over the long-
term, will shift impervious surfaces and storm drain infrastructure from gray, or traditional
storm drain infrastructure where runoff flows directly into the storm drain and then to
receiving water, to green, which is a more resilient, sustainable system that slows runoff
using vegetated systems; and
WHEREAS, GSI can provide additional benefits such as mitigating for the urban
heat island effect, improving local air quality, reducing localized flooding, providing carbon
sequestration opportunities, and improving the streetscape enhancing the bicycle-
pedestrian experience; and
WHEREAS, the City of Dublin has demonstrated its commitment to an
environmentally sustainable future through its policy goals and actions and intends to
incorporate GSI into projects when doing so will benefit the environment and when a
funding source for GSI has been identified; and
WHEREAS, in order to be in compliance with the MRP, a Green Stormwater
Infrastructure Plan has been prepared for the City of Dublin.
125DRAFTAppendix I City of Dublin Green Stormwater Infrastructure Plan
NOW, THEREFORE, BE IT RESOLVED, that the City Council of the City of Dublin
does hereby approve the City of Dublin Green Stormwater Infrastructure Plan, attached
as Exhibit A.
BE IT FURTHER RESOLVED that the City Manager, or designee, is authorized to
update the Green Stormwater Infrastructure Plan, including maps and potential project
locations, as necessary and identified through an adaptive management process.
PASSED, APPROVED AND ADOPTED this 18th day of June 2019 by the
following vote:
AYES:
NOES:
ABSENT:
ABSTAIN:
_____________________________________
Mayor
ATTEST:
_______________________________________
City Clerk