GSP Annual Report
1-005 SCOTT RIVER VALLEY
2022 (OCT. 2021 - SEP. 2022)
Single Annual Report
GSP Annual Report Information Comments
A Groundwater Extraction
Total Groundwater Extractions (AF)
30,000
Water Use Sectors
1,000
0
29,000
0
0
0
0
B Groundwater Extraction Methods
Meters
0
Electrical Records
0
Land Use
0
Groundwater Model
29,000
Estimate
60-70 %
Estimated values are based on the Scott Valley Intergrated Hydrologic Model with a 30% reduction in groundwater pumping due to local cooperative solutions (LCS) developed under the State Water Resources Control Board (SWRCB's) Drought Emergency Order for Scott Valley
Accuracy based on uncertainty in inputs and model uncertainty.
Other
1,000
Estimate
Other
Urban groundwater extraction is estimated as 1,000 acre-feet, calculated based ond a Scott Valley population of 3,520 people (per the 2019 Basin prioritization).
Accuracy dependant on the accuracy of the population and accuracy of the estimated water use per person used to calculate urban groundwater exraction.
C Surface Water Supply
Total Surface Water Supply (AF)
26,000
Methods Used to Determine
The value is estimated using the current calibration of the soil water budget model used by the UC Davis Scott Valley Intergrated Hydrologic Model, and includes the estimtate from the soil water budget model published by Foglia et al., 2013a,b, available at http://groundwater.ucdavis.edu/Research/ScottValley/. A drought emergency curtailment order went into effect for the growing season of 2022, but is not thought to have reduced the amount of surface water use significantly compared to the full allocation of previous years.
Water Source Types
0
0
0
26,000
0
0
0
0
D Total Water Use
Total Water Use (AF)
56,000
Methods Used to Determine
Sum of surface and groundwater use.
Water Source Types
30,000
26,000
0
0
0
Water Use Sectors
1,000
0
29,000
0
0
0
26,000
Surface water use is not divided into water use sectors and is estimated as a total value.
E Change in Storage
Method used to calculate change in storage
In the private monitoring well network (13 wells), water levels measured in March of 2022 were, on average, 0.1 feet higher than during the same period in 2021 indicating an overall stability in groundwater storage (see water level report at http://groundwater.ucdavis.edu/Research/ScottValley/). In DWR's Water Data Library, two wells have water levels documented for both, spring 2021 and spring 2022. Between spring 2021 and spring 2022 water levels in these two wells decreased by 4.7 feet, on average (https://sgma.water.ca.gov/webgis/?appid=SGMADataViewer#gwlevels; accessed February 9, 2022). These two wells were not considered to compute groundwater storage change between 2021 and 2022. The current UC Davis Scott Valley Integrated Hydrologic Model (https://doi.org/10.1029/2018WR024209) was used to determine the relationship between water levels at the original 32 locations of the private monitoring well network and total groundwater storage in the Scott Valley aquifer, which extends over approximately 50,000 acres of alluvium, for the period from 10/1/1990 to 9/30/2011. Based on simulated annual change in storage and simulated water levels at the location of the original 32 private monitoring wells, it was estimated that the average total annual groundwater storage change is between 3 thousand and 5 thousand acre-feet for each one foot change in average water levels in the monitoring well network during January through March. The statistical uncertainty of the estimated storage change of zero acft is +/-2.5 thousand acre-feet.
