HomeMy WebLinkAbout8.1 KoopmanCanyon CITY OF DUBLIN
AGENDA STATEMENT
City Council Meeting Date: October 26, 1987
SUBJECT: Request for Acceptance of Maintenance - Koopman Canyon
Trash Rack
EXHIBITS ATTACHED: 1) Letter from Estate Homes
2) Copy of USGS Map Showing Watershed
3) Letter from Bissell & Karn Regarding Trash Rack
4) Plot Plan Showing Easement
5) Sketch of Stairs
6) Slides of Facility to be Shown at Meeting
RECOMMENDATION: Approve acceptance of maintenance of the trash rack
behind Lot 17 Fenwick Court of Estate Homes Tract
i\ 4749, subject to Estate Homes' completion of
construction of the trash rack to the satisfaction of
the City Engineer, providing an all-weather vehicle
access to the top of the slope and pedestrian access
to the trash rack.
FINANCIAL STATEMENT: Maintenance Staff will monitor the trash rack as part
of their storm patrol and remove debris if necessary.
The cost of constructing the trash rack and access
will be fully paid by the developer.
DESCRIPTION:
Koopman Canyon, just north of the Dublin City Limit and behind the
Laborers Training Camp, is approximately 150 acres in size, and all the water
collected from this watershed drains to and is picked up by a 48" diameter
pipe behind Lot 17 of Tract 4749.
For somewhat over a year, the City and Estate Homes have been discussing
the possibility of the City's assumption of maintenance of this drainage
facility, including the trash rack that prevents debris from washing into the
storm drain system and the winch used for raising and lowering the rack.
Staff has continued the policy established by the County to not maintain
storm drain facilities until they begin picking up water from public streets
or from lands controlled by the City; however, an exception is being
recommended in this case for the following reasons:
1) There is a heavily wooded large watershed above this private
residence, over which the residence owner has no control.
2) Expected debris removal during a heavy storm is too large a job for
one property owner, as maintenance personnel and equipment will be
required.
To assure that heavy debris does not enter the City's storm drain
system, and to lessen the risk of flooding of residences downstream of this
watershed, Staff recommends acceptance of maintenance of the trash rack,
subject to certain improvements being installed to allow ease of access by
City maintenance crews. The developer will be required to meet standards
established by the City Engineer and to address items noted in Exhibit 3. If
the City Council concurs with this recommendation, it will be necessary to
amend the Final Map originally recorded and accept a maintenance easement.
This item would be placed on a future agenda.
ITEM NO. 811,1 COPIES TO: Garry Brown, Estate Homes
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Estate Homes
3001 SOUTH WINCHESTER BOULEVARD . CAMPBELL, CALIFORNIA 95008 . 408/374-7910
August 26, 1987
Mr. Lee Thompson, City Engineer
City of Dublin
6500 Dublin Blvd., Suite D
Dublin, California 94568
Dear Mr. Thompson:
This letter is in regard to the City of Dublin taking over main-
tenance of the trash rack and winch located in the Koopman Creek
Channel behind the property at 11550 Fenwick Court, Lot 17, Block A,
Tract 4749. By direction of the City, subsequent to approval of
original grading and drainage plans, we built and incurred the ex-
pense for this trash rack and winch. As the trash rack and sur-
rounding area requires periodic maintenance beyond the scope of
which the homeowner can be held responsible, we propose that this
responsibility become that of the City of Dubli~,
In accordance with our previously submitted drawings and your sup-
plements and verbal understandings, we will provide the following
upon written acceptance of this proposal:
1. The existing 10 ft. wide easement from the sidewalk to
the top of the slope will be concrete with 6"x6"-10 gauge
reinforcing wire mesh as per your request.
2. The existing 10 ft. wide access gate will have a lock to
which the City of Dublin and the homeowner will have a key.
3. Stairs with handrails from the top of the slope down to
the trash rack, concrete landings at the top and bottom
of stairs, concrete piers to support stair framing, and
treated wood stair treads as per your request.
4. The existing gate at the bottom of the slope will have a
lock to which the City of Dublin will exclusively have
the key.
We await your written response to this proposal.
O~I~
EXH~BIT i
GBln
BH- BISSELL &
_ KARN.INC.
4637 Chabot Dr.. Suite 204
Pleasanton, CA 94566
(415) 463-1l6OO
May I, 1987
Job #864097.10
Mr. Lee Thompson, city Engineer
Ci ty of Dublin
6500 Dublin Boulevard
Dublin, California 94568
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Dear Mr. Thompson:
PUBLIC WORKS
Re: Koopman Canyon Trashrack, Design Conunents by City
This letter is a response to our conversation of Monday of this week. I
have reviewed the City's comments of October, 1986 and have noted the
following significant discrepancies with the trash rack as shown on
the record drawings:
1. No locking mechanism exists for preventing entry to the culvert. The
grate can be opened easily by one or two people and entrance can be
gained to the culvert with the existing arrangement~ A lock should be
designed and installed. It should be removable even when the grate is
submerged.
2. The welds on the trash rack have been done already, and we have no idea
how well they were done. It would be a good idea to send an inspector
out to examine them.
3. The winch, cable, and pulley have already been installed. As with the
welds, these should be inspected.
4. As noted on the record drawings, the winch pole is anchored in concrete
placed behind the headwall. The adequacy of this installation is still
in doubt since we have no idea how far the pole penetrates the ground,
nor how much cement was placed in the hole.
5) The 2" steel pipes which were to be set and grouted into the headwall
were not. This doesn't seem to present a problem since the anchor bolts
will provide plenty of resistance to lateral forces (except possibly for
complete blockage of the rack under high head).
6. There is a discrepancy between the cable attaching loop hole diameter
shown on page 5 of 7 and that shown on page 2 of 7. The actual diameter
of the hold should be measured by an inspector.
EAP.1.44
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BISSELL & KARN.INC.
May l, 1987
Job #864087.l0
Page 2
If you have further questions on this matter, please give me a call.
Very truly yours,
BISSELL & KARN, INC.
by~'aP
Eric A. Petrel
Water & Wastewater Eng.
EAP: smb
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EAP.1.44
157.00
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RECEIVED
OCT 21198/'
PUBLIC WORKS
Revised 5- 1-87
B r ~ ~ BARBARA COllEY, R.C.E..
""6.:J ~ Consulting Civil Engineer
S040 "Nt nu TllU'^a. CAMI'IIEtl. CA 9SlIlll 408/866-7255
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