To: Board of Supervisors
From: Warren Lai, Public Works Director/Chief Engineer
Report Title: APPROVE a second amendment to the Cooperative Implementation Agreement with the State of California, Department of Transportation, and a Reimbursement Agreement with the San Mateo County Flood and Sea Level Rise Resiliency District.
Recommendation: Recommendation of the County Administrator
RECOMMENDATIONS:
APPROVE and AUTHORIZE the Public Works Director, or designee, to execute a second amendment to the Cooperative Implementation Agreement with the State of California, Department of Transportation (Caltrans), and APPROVE and AUTHORIZE the Public Works Director, or designee, to execute a reimbursement agreement with the San Mateo County Flood and Sea Level Rise Resiliency District, aka OneShoreline, effective September 8, 2026, to allow $226,810 in remaining state funds to be reallocated to the I-380/US-101 Interchange detention basin and 7th Ave. green infrastructure project, a public purpose, to meet the agencies’ obligations under their Municipal Regional Stormwater National Pollutant Discharge Elimination System (NPDES) Permit, Countywide.
FISCAL IMPACT:
This project is funded 95% through the Caltrans Cooperative Implementation Funds and 5% Stormwater Utility Assessment 17 funds. Project 7517-6W7080
BACKGROUND:
Contra Costa County (County) is one of 79 Bay Area permittees under the San Francisco Bay Region Municipal Regional Stormwater NPDES Permit (MRP). One of the current MRP requirements is to reduce trash discharging from the County municipal separate storm sewer system (MS4) by 100% by 2025. As part of this effort, the County looked for opportunities to install full trash capture systems to prevent trash from flowing from MS4s to creeks and the Bay.
Caltrans is also required to reduce trash from its highways, which travels through communities and has stormwater drainage systems that tie into MS4s. Caltrans has been looking for opportunities to partner with municipalities to implement trash and other pollutant control measures.
The County entered into a Cooperative Implementation Agreement with Caltrans June 24, 2020. Under the Cooperative Implementation Agreement and the amended agreement, five large full trash capture devices were installed in the Tara Hills (unincorporated San Pablo), Bay Point, and the Saranap areas.
The County is maintaining these systems within the County road right of way. Both Caltrans and the County will receive credits for the reduction of trash and possibly from the removal of polychlorinated biphenyls (PCBs) and mercury, bound to sediment, from the MS4.
There are some additional funds leftover but no current project opportunities. The County is working with Caltrans and the San Mateo County Flood and Sea Level Rise Resiliency District, aka One Shoreline, to use these funds for other projects that reduce pollutants, such as trash and PCBs, in the Bay and receive credit for those pollutant reductions under the MRP.
CONSEQUENCE OF NEGATIVE ACTION:
Without approval, the state and Bay Area agencies will have less funding available for projects that reduce pollutants into the San Francisco Bay.