HomeMy WebLinkAboutMINUTES - 10122010 - C.05RECOMMENDATION(S):
APPROVE the Marsh Creek Reservoir Sediment Removal Project [DCD-CP#10-53] Project
No.: 7521-6D9104; and
FIND the project is a California Environmental Quality Act (CEQA), Class 1 Categorical
Exemption, pursuant to Article 19, Section 15301(1) (d) of the CEQA Guidelines; and
DIRECT the Director of Conservation and Development to file a Notice of Exemption with
the County Clerk; and
AUTHORIZE the Chief Engineer to arrange for payment of $25 fee to Conservation and
Development for processing, and a $50 fee to the County Clerk for filing the Notice of
Exemption.
FISCAL IMPACT:
There is no impact to the County General Fund. This project is funded by Flood Control
Zone 1 funds (100%).
APPROVE OTHER
RECOMMENDATION OF CNTY ADMINISTRATOR RECOMMENDATION OF BOARD COMMITTEE
Action of Board On: 10/12/2010 APPROVED AS RECOMMENDED OTHER
Clerks Notes:
VOTE OF SUPERVISORS
AYE:John Gioia, District I Supervisor
Gayle B. Uilkema, District II
Supervisor
Mary N. Piepho, District III
Supervisor
Susan A. Bonilla, District IV
Supervisor
Federal D. Glover, District V
Supervisor
Contact: Hillary Heard,
313-2022
I hereby certify that this is a true and correct copy of an action taken and entered on the minutes of the Board
of Supervisors on the date shown.
ATTESTED: October 12, 2010
David J. Twa, County Administrator and Clerk of the Board of Supervisors
By: EMY L. SHARP, Deputy
cc: S. Ybarra, Auditor-Controller, S. Alcantar, DCD, P. Denison, Finance, L. Chavez, Environmental, H. Heard, Environmental, A. Knapp, Maintenance,
P. Detjens, Flood Control, N. Chuhak, Environmental, T. Torres, Environmental
C. 5
To:Board of Supervisors
From:Julia R. Bueren, Public Works Director/Chief Engineer
Date:October 12, 2010
Contra
Costa
County
Subject:Approve Marsh Creek Reservoir Sediment Removal Project and make related findings under CEQA
BACKGROUND:
The project consists of sediment removal within Marsh Creek Reservoir at the intake
structure that meters flows from the reservoir downstream to Marsh Creek. Marsh Creek
Reservoir was designed specifically for the purpose of flood protection to the surrounding
urban environment, which includes homes, local industries and schools. Periodic
maintenance of the reservoir is required in order to ensure the reservoir continues to
maintain functionality. Recent observations indicate that the sediment and debris level,
due in part to beaver activity, around the intake structure has cut off flows exiting the
reservoir. The intake structure cannot function appropriately without removal of the
sediment and debris. Flood Control District staff has coordinated with a biological
consulting firm and engineering firm regarding the feasibility of clearing the blocked
structure without eradicating the beavers. The biologists and engineers that have
considered this option have arrived at the collective conclusion that the beavers cannot
remain within the reservoir without creating an unacceptable risk of flooding to the City
of Brentwood. California Department of Fish and Game (CDFG) has issued a
depredation permit for the beavers since trapping and relocating the beavers is prohibited
by state law.
Approximately 200 cubic yards of sediment will be removed from the area around the
inlet structure. The sediment has been analyzed for heavy metals due to known historical
mercury mining activity upstream. The sediment has been determined to be below state
levels for toxicity; therefore, the sediment removed from the reservoir will be disposed of
at an upland location within the Flood Control District’s holdings at the reservoir. A
biologist will be on-site during sediment and debris removal activities to monitor for the
presence of wildlife in the vicinity of the structure. If any listed species are observed,
work will cease and U.S. Fish and Wildlife and CDFG will be contacted for guidance. In
order to minimize any impact to the reservoir and the downstream channel during
construction, the project has been designed to include several Best Management Practices
(BMPs). These BMPs will ensure that no sediment is transported downstream as a result
of the project. Additional BMPs include daily trash removal from the site to ensure the
area is maintained in a clean condition, and fueling and maintenance of equipment at
designated areas away from the reservoir.
To minimize impact to adjacent annual grassland vegetation in the reservoir, access to the
intake structure will be accomplished via the existing access road along the base of the
dam. No riparian or wetland vegetation will be removed. Work will be conducted with a
long reach excavator or the Kaiser Spyder, an articulated arm excavator that has less
weight impact than other pieces of heavy equipment.
CONSEQUENCE OF NEGATIVE ACTION:
Delay in approving the project will result in a delay of maintenance activities and create
an unacceptable risk of flooding to the City of Brentwood.
CHILDREN'S IMPACT STATEMENT:
Not Applicable.
ATTACHMENTS
Initial Study of Environmental Significance
Figure 1 - Project Location Map
Figure 2 - Vicinity Map
Notice of Exemption