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 GRAPEX Project and Application of Multi-Scale Remote Sensing Evapotranspiration Toolkit for Mapping Crop Water Use and Crop Stress for Improved Irrigation
RECOMMENDATION
title
The TAG will receive an update on the use of satellite and land-based remote sensing data for analysis of evapotranspiration and information that can be used to refine vineyard water use estimates for Napa Valley Subbasin integrated hydrologic modeling purposes.
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Procedure
Staff introduces.
Questions and answers with the TAG.
Public comments.
BACKGROUND AND DISCUSSION
Remotely-sensed evapotranspiration (ET) estimates informed the development of the Napa Valley Integrated Hydrologic Model (NVIHM) for the Groundwater Sustainability Plan (GSP). These estimates used data from 2014 to develop crop coefficients for black and white grapes in Napa Valley. As previously presented to the TAG, the total water use, as measured by ET, varies across the Napa Valley Subbasin. The initial crop coefficients developed during GSP development provided the foundation for determining applied water requirements, for both surface and groundwater, for irrigated acreages within the NVIHM. Refining the estimates of applied water is a priority during GSP implementation. Since the initial NVIHM development, multiple data sources, including local sensors as well as remotely sensed data, are being used to update modeled ET.
Field measurements of ET using surface renewal methods by Tule Technologies were presented at the October 2022 TAG meeting. The measured data provides daily, field-scale measurements of ET. As previously discussed with the TAG, the use of local data is necessary to refine crop coefficients in Napa County. An overview of remotely sensed ET ...
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