GSP Annual Report
5-021.64 NORTH AMERICAN
2021 (OCT. 2020 - SEP. 2021)
Single Annual Report
GSP Annual Report Information Comments
03/31/2022 2:43 PM
2021 (OCT. 2020 - SEP. 2021)
Single Annual Report
A Groundwater Extraction
Total Groundwater Extractions (AF)
381,300
Water Use Sectors
58,400
25,000
290,800
0
0
0
7,100
Groundwater remediation pumping
B Groundwater Extraction Methods
Meters
118,040
Direct
90-100 %
Meters are combination of propeller and magnetic meters.
Meters are calibrated at regular intervals per meter specifications to maintain accuracy at about 5% or better.
Electrical Records
0
Land Use
0
Groundwater Model
263,260
Estimate
Other
The CoSANA model is a quasi-three-dimensional finite element model developed using the Integrated Water Flow Model 2015 software package developed by DWR. The model is calibrated over a hydrologic period from WY 1994 through WY 2018 by comparing simulated evapotranspiration, groundwater levels, and streamflow records with historical observed records.
The CoSANA model is used to estimate agricultural and other rural groundwater extractions. The estimates provided by the CoSANA model have a qualitative accuracy medium to high. This equates to about an 80% level of accuracy for agricultural extractions.
Other
0
C Surface Water Supply
Total Surface Water Supply (AF)
249,000
Methods Used to Determine
Meters and weirs, estimated
Water Source Types
96,900
0
0
145,500
0
6,600
0
0
D Total Water Use
Total Water Use (AF)
630,300
Methods Used to Determine
Direct through meters and weirs, estimated by groundwater model
Water Source Types
381,300
242,400
6,600
0
0
Water Use Sectors
139,610
60,000
423,590
0
0
0
7,100
Groundwater remediation pumping
E Change in Storage
Method used to calculate change in storage
Annual change in storage was determined for the end of the water year by using measured groundwater elevations at a consistent set of wells measured in fall 2020 and again in fall 2021. A change in groundwater levels contour map comparing 2020 to 2021 was prepared. The difference in groundwater elevation maps were then used to calculate a weighted average change in groundwater levels throughout the Subbasin. The average change in groundwater levels were then multiplied by the average specific yield of the Subbasin, which was estimated at 8.4 percent based on textural analysis of well driller logs as part of development of DWR?s Sacramento Valley Simulation (SVSim) Model. The resulting calculated change in storage at the end of WY 2021 (fall 2020 ? fall 2021) was about -110,500 AF.
