To: The Contra Costa County Flood Control and Water Conservation District Board of Supervisors
From: Warren Lai, Public Works Director/Chief Engineer
Report Title: Approve Amended Agreement with the Central Contra Costa Sanitary District for the Grayson and Walnut Creeks Levee Improvement Project. Project No. 7520-6B8348
☒Recommendation of the County Administrator ☐ Recommendation of Board Committee
RECOMMENDATIONS:
APPROVE and AUTHORIZE the Chief Engineer, Contra Costa County Flood Control and Water Conservation District (FC District), or designee, to execute an amended agreement (Agreement) with the Central Contra Costa Sanitary District (CCCSD) for implementation of the Grayson and Walnut Creeks Levee Improvement Project (Project), Martinez area.
FISCAL IMPACT:
The total estimated cost of the Project is approximately $14 million. This includes costs for preparing design and construction documents, obtaining permits, preparing California Environmental Quality Act (CEQA) documents, construction contracting, and related project management and administration. The terms of the Agreement provide for mutual cost sharing with the CCCSD. The FC District’s share will be funded through Flood Control Zone 3B funds.
BACKGROUND:
The FC District and CCCSD are jointly implementing the Project along Walnut Creek and Grayson Creek to protect the CCCSD treatment plant from riverine flooding. An agreement for the Project was approved by the Board on December 8, 2020. Since that time, several changes to the project scope and budget have occurred, requiring revisions to the original agreement. The attached amended Agreement is proposed to accommodate the updated project and outlines the work efforts and total expenditures (past and anticipated) for the mutual cost-sharing arrangement.
The Project is designed to reduce flood risk to CCCSD’s wastewater treatment plant in Martinez. The CCCSD and the FC District previously collaborated in 2007 to implement the Walnut Creek Interim Protection Measures, which raised the levees surrounding the CCCSD treatment plant to provide protection against the 100-year flood level. The current Project builds upon that effort and is intended to provide an enhanced level of flood protection.
Construction of the Project is anticipated to begin in summer 2026. A separate Board approval will be sought early next year to award the construction contract. The Board has previously approved the Project, its CEQA findings and determination, and property transactions between the FC District and CCCSD. The FC District and CCCSD will continue to work together in an equal partnership to advance the Project.
Key provisions of the proposed Agreement are as follows:
• The FC District will serve as the lead agency for Project implementation, including developing 100% design and construction documents, advertising, awarding, and administering a construction contract to complete the Project. Upon completion, the FC District will own and maintain the Project improvements located within the FC District’s rights-of-way.
• The FC District and CCCSD will share the mutually beneficial costs and expenses of the Project equally. Costs and expenses that benefit only one party will be borne solely by the benefiting party.
• The FC District and CCCSD will require their contractors and consultants for the Project to maintain additional insurance coverages.
• The FC District and CCCSD will require their contractors and consultants for the Project to defend and indemnify both parties and their respective governing bodies, officers, agents, and employees.
The CCCSD Board has approved the Agreement and authorized the CCCSD General Manager to execute the Agreement with the FC District for Project implementation.
CONSEQUENCE OF NEGATIVE ACTION:
If the Agreement is not approved, the Project will not be implemented.