To: The Contra Costa County Flood Control and Water Conservation District Board of Supervisors
From: Warren Lai, Public Works Director/Chief Engineer
Report Title: Rescind Board Action from April 28, 2026, Pertaining to an Interagency Agreement with Aquatic Science Center; and Approve and Authorize Execution of the Revised Interagency Agreement.
☒Recommendation of the County Administrator ☐ Recommendation of Board Committee
RECOMMENDATIONS:
RESCIND Board action of April 28, 2026 (C.141), which approved execution of an Interagency Agreement with Aquatic Science Center (Agency); and APPROVE and AUTHORIZE the Chief Engineer, Contra Costa County Flood Control and Water Conservation District (Flood Control District) or designee, to execute the revised Interagency Agreement with the Agency, in an amount not to exceed $1,000,000, to synthesize historical maps, reports, photographs, written accounts, field observations, and botanical records to characterize the ecological, hydrologic, and geomorphic conditions of the Walnut Creek Watershed prior to major Euro-American modification. Additionally, a fully illustrated report and GIS database to support a landscape change analysis comparing historical habitat extent and distribution to present-day conditions will be provided. This interagency agreement is from June 23, 2026 through June 22, 2031, and covers portions of Walnut Creek, Concord, Pleasant Hill, Martinez, Lafayette, Moraga, Danville, San Ramon, and unincorporated County areas.
FISCAL IMPACT:
The Project is 100% funded by the Flood Control District Zone 3B funds. Project No. 7520-6B8290
BACKGROUND:
On April 28, 2026, the Board of Supervisors approved an Interagency Agreement with the Agency in an amount not to exceed $1,000,000, for the period of April 28, 2026 through April 27, 2029, to conduct a historical ecology study of the Walnut Creek Watershed that will reconstruct pre-development ecological and hydrological conditions and produce a technical report and GIS-based mapping to support long-term watershed management and multibenefit planning. Following Board approval, the Agency proposed revisions to the agreement, and the Flood Control District determined that addressing these changes, along with anticipated needs for a longer project timeline, would be more appropriately accomplished by rescinding the prior approval and returning with an updated agreement to minimize the number of future amendments.
After Board approval, the Agency reviewed the agreement in more detail and requested several administrative updates, including revised contact information, terminology clarifications, and incorporation of its deliverables schedule. The Agency also indicated that the project is expected to take approximately 3.5 years to complete, which exceeds the original 3-year term. While these revisions do not change the overall scope or cost of work, Flood Control District staff determined that, given the complexity of the study and the likelihood of unforeseen delays, it would be prudent to restructure the agreement with a maximum 5-year term to reduce the need for multiple amendments over the life of the project.
This staff report seeks Board authorization to rescind the Board action of April 28, 2026, and approve a revised agreement reflecting updated work dates of June 23, 2026 through June 22, 2031.
CONSEQUENCE OF NEGATIVE ACTION:
Without the approval of the Board, the Flood Control District will be unable to execute this interagency agreement and will be required to return to the Board in the future to amend the end date. If an agreement is not executed, the Flood Control District must continue to seek potential mitigation opportunities without the benefit of a comprehensive ecological understanding of watershed functions and processes.