GSP Annual Report
5-021.57 VINA
2023 (OCT. 2022 - SEP. 2023)
Single Annual Report
GSP Annual Report Information
Correspondences
Comments
A Groundwater Extraction
Total Groundwater Extractions (AF)
242,000
Water Use Sectors
21,900
0
218,600
0
0
0
1,500
Rural Residential
B Groundwater Extraction Methods
Meters
21,900
Direct
5-10 %
Metered Municipal Wells
Metered connection maintained by California Water Service and Durham Irrigation District
Electrical Records
0
Land Use
218,600
Estimate
20-30 %
Land use estimates were derived from crop mapping and CropScape survey results
Typical uncertainty for water balance calculation
Groundwater Model
0
Other
1,500
Estimate
10-20 %
Rural residential groundwater extraction is estimated based on California Water Service Company's 2020 Urban Water Management Plan 2020 usage of an average per capita water use of 181 gallons per capita per day. Population data from the 2020 census was coupled with parcel data to identify total population not serviced by municipal supplies.
Uncertainties are from population estimates and gallon per capita per day estimates
C Surface Water Supply
Total Surface Water Supply (AF)
27,200
Methods Used to Determine
Diversions for local supplies are estimated based on historic State Water Resource Control Board eWRIMS (Electronic Water Rights Information Management System) data for total diversions. Surface water delivery estimates are based on historic deliveries in the area that have occurred in dry and critical years.
Water Source Types
0
0
0
27,200
0
0
0
0
D Total Water Use
Total Water Use (AF)
269,200
Methods Used to Determine
Methods used are a combination of estimates based on land use and population/ per capita water use, metered municipal water use, and estimates based on historic water rights data for dry and critical years.
Water Source Types
242,000
27,200
0
0
0
Water Use Sectors
21,900
0
245,800
0
0
0
1,500
Rural Residential
E Change in Storage
Method used to calculate change in storage
Change in groundwater storage was estimated based on change in measured spring-to-spring groundwater levels at each RMS well, multiplied by the area of a Thiessen polygon surrounding that RMS well (defining a representative area for each RMS well) and a representative storage coefficient of 0.1 for the principal aquifer.
