TO: Technical Advisory Group for the Napa County Groundwater Sustainability Agency
FROM: Brian D. Bordona, Director of Planning, Building and Environmental Services
REPORT BY: Jamison Crosby, Natural Resources Conservation Manager
SUBJECT: State Water Board: Water Supply and Demand Assessment for the Napa River Watershed
RECOMMENDATION
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Receive a presentation from staff of the State Water Resources Control Board (SWRCB) Supply and Demand Assessment Unit and Paradigm Environmental, Inc. on Modeling Water Supply and Demand in the Napa River Watershed.
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Staff introduces the item
Presentation
Questions and answers from the TAG
Public comments
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BACKGROUND AND DISCUSSION
The State Water Resources Control Board (State Water Board) is responsible for allocating surface water through California's water rights priority system. Watershed-specific supply information from year to year is generally lacking, making water management planning difficult, especially in times of water shortage. Recent droughts (2013-2016, 2021-2023) highlighted the need for specialized data and tools to assess water availability and water demand and to evaluate how limited water resources are allocated. The State Water Board is initiating a new effort that will use an approach similar to the one used for the Russian River during the most recent drought. It will enable the State Water Board to prepare for future dry conditions in other watersheds and provide data to help local water managers better understand supply constraints, develop local responses and plan for droughts.
In 2021, in response to the drought emergency in Sonoma and Mendocino Counties, the State Water Board developed tools and information to better understand water supply and demand in the Russian River watershed. Staff developed a water supply model and evaluated water diversion data to estimate surface water demands. Staff also used a tool to allocate water to right holders based on the modeled available su...
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