Re: July 8, 2025 City Council Meeting Item 10.B Direction to WAC re MMWDistrict agreement.
Subject: Ask for a policy level discussion on the impacts to the shared Cotati aqueducts/water transmission systems of the proposed water supply agreement between Marin Municipal Water District (MMWD) and Sonoma Water
Dear Mayor Ford, Vice Mayor Lemus, and Councilmembers Savage, Sparks, and Harvey, For item 10.B, there doesn't seem to be any analysis of the proposed agreement in terms of its impacts on Cotati's water supply system. Since the aqueducts are shared, I wonder if there has been consultation with Rohnert Park and Petaluma? This item could be continued to the next meeting for a more meaningful context. The agreement for the WAC vote isn't due until August 4th; it was presented at the TAC on June 2nd.
This item appears to be accepting potentially significant impacts to the aqueduct capacity. I would have expected some basic information on the current system's water capacity, projected capacity loading for Cotati (and Rohnert Park), and future goals for winter storage. Is it likely that Cotati/Rohnert Park/Petaluma could implement groundwater storage in the future? Marin Municipal Water District (MMWD) is at the “end of the pipe”. The current agreement requires greater usage of the water supply aqueducts that first passes Cotati (and Rohnert Park and Petaluma).
A back of the envelop calculation shows MMWD almost doubling requirements, from current FY2023- 2024 usage of 5,774AF to 10,000AFY. For Marin County as a whole, this is increasing from current 10,909AF (52% total delivery) to potentially 15,125AF (72% total delivery).
Starting at Packet Pg 199, the Analysis is missing any policy level options on how this agreement could impact Cotati, and there are no maps to make the current restrictions on aqueduct capacity understandable. It’s a particularly dense packet, with no visual system level view.
On PacketPg 200, there is one buried sentence: “These operational changes would have no impact on Cotati’s priority and contractual amounts”
If you recall Lake Sonoma came into operation in 1983, and as of today Sonoma Water has on its website at bottom “Lake Sonoma is about four times larger than Lake Mendocino and can provide multiple years of water supply. Lake Sonoma relies on rainfall to fill and supports a dynamic and fragile ecosystem in Dry Creek that includes the endangered coho salmon and threatened steelhead trout. Lake Sonoma provides a majority of Sonoma Water's service area with its drinking water.” In the document before you there appears a legal fiat on MMWD (DRAFT May 2, 2025), connecting the 1955 event to build Lake Sonoma to reduce reliance on the Eel River transfers using 70+ river miles of upper Russian River, as still being of the same value today.
Pkt PgPg224 <quote> Recital O) Recital E. in the Supplemental Agreement recognized that one of the reasons for that agreement was “to accommodate the Agency’s [Sonoma Water] efforts to attempt to ensure a continuation of Pacific Gas and Electric Company’s historic diversions of Eel River water to the Russian River and to increase the reliability of the water supply deliverable to [MMWD].” The need to ensure the continuation of such flows for the benefit of all of Sonoma Water’s Water Contractors was heightened by the amendments made by the Federal Energy Regulatory Commission in 2004 to Pacific Gas & Electric Company’s (PG&E) license for the Potter Valley Project, which reduced such flows and subsequently by PG&E’s decision to pursue surrender of its license to operate the Potter Valley Project and propose its decommissioning. By entering into this Agreement, the parties recognize the ongoing importance of the continuation of flows from the Eel River to the Russian River for the benefit of all of Sonoma Water’s customers.
Recital E) In 1955, Sonoma Water (then called the “Sonoma County Flood Control and Water Conservation District”) sold general obligation bonds to raise $5,650,000, which it paid to the United States for the reimbursable costs of the water-storage element of the Coyote Valley Project. Parts of the property taxes paid since 1955 by taxpayers within Sonoma County have been used to make payments on these bond obligations and to fulfill other obligations to the United States Government for the Russian River Project. <end quote>
Sincerely
Neil Hancock, Cotati July 6, 2025