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: Presentation on Interconnected Surface Water (ISW) and Groundwater Dependent Ecosystem (GDE) Workplan and CEFF Assessment
RECOMMENDATION
title
Provide an update on the Interconnected Surface Water (ISW) and Groundwater Dependent Ecosystem (GDE) Workplan implementation and the CEFF assessment.
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Procedure
Staff introduces.
Questions and answers with the TAG.
Public comments.
BACKGROUND AND DISCUSSION
The Napa Valley Subbasin Groundwater Sustainability Plan (GSP) and the Interconnected Surface Water and Groundwater Dependent Ecosystems Workplan (Workplan) both recommended using the California Environmental Flows Framework (CEFF) to assess ecosystem instream flow needs in the Napa Valley Subbasin (Subbasin). CEFF is divided into three sections. Section A includes identifying ecological management goals and the functional flow components (e.g., maintain suitable habitat conditions for juvenile steelhead rearing) required to support the ecosystem functions that correspond to each management goal. CEFF Section B includes developing ecological flow criteria for flow components by developing detailed conceptual models relating the functional flow components to ecological management goals and quantifying flow-ecology relationships while taking non-flow factors (e.g., channel incision, physical habitat, and potentially stream temperature) into account. In Section C, which will be completed after implementation of the Workplan, ecological flow requirements are considered along with other water users to develop environmental flow recommendations. The assessment focuses on dry-season baseflow (generally June through October), which is strongly tied to groundwater management in the Napa Valley Subbasin and crucial for supporting speci...
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