A Groundwater Extraction

Total Groundwater Extractions (AF)

Water Use Sectors

Rural Domestic and Small Public Water System

B Groundwater Extraction Methods

Meters

Metered Municipal Wells

The level of accuracy is rated on a qualitative scale of low, medium, and high. The Metered groundwater extraction accuracy rating is high.

Electrical Records

Land Use

Land use data along with climate and soil data were analyzed and processed using the soil-water balance model that was developed for the PasoRobles Groundwater Basin Model Update (GSSI, 2014).

The level of accuracy is rated on a qualitative scale of low, medium, and high. The Land Use accuracy rating is medium.

Groundwater Model

Rural Domestic and Small Public Water Systems groundwater extractions in the Subbasin were estimated using the groundwater model update completed for the GSP (M&A, 2019).

The level of accuracy is rated on a qualitative scale of low, medium, and high. The Rural Domestic and Small Public Water Systems groundwater extraction accuracy rating is low-medium.

Other

C Surface Water Supply

Total Surface Water Supply (AF)

Methods Used to Determine

Metered

Water Source Types

D Total Water Use

Water Source Types

Water Use Sectors

Rural Domestic and Small Public Water System

E Change in Storage

Method used to calculate change in storage

From PDF page 37 of Report [SECTION 7: Change in Groundwater in Storage (§ 356.2[b][5])]:

Annual changes in groundwater elevation in the Paso Robles Formation Aquifer for WY 2021 are derived
from comparison of fall groundwater elevation contour maps from one year to the next. For this analysis, fall
2020 groundwater elevations were subtracted from the fall 2021 groundwater elevations resulting in a map
depicting the changes in groundwater elevations in the Paso Robles Formation Aquifer that occurred during
WY 2021 (see Figure 10). This groundwater elevation change map is based on a reasonable and thorough
analysis of the currently available data. As stated in Section 3, groundwater elevation data for the Alluvial
Aquifer are too limited to prepare annual groundwater elevation contour maps. Therefore, the change in
groundwater in storage analysis is limited to the Paso Robles Formation Aquifer for this Water Year 2021
Annual Report.

The groundwater elevation change map presented above represents a volume change within the Paso
Robles Formation Aquifer for WY 2021. The volume change inferred from the groundwater elevation change
map (Figure 10) represents a total volume, including the volume displaced by the aquifer material and the
volume of groundwater stored within the void space of the aquifer. The portion of void space in the aquifer
that can be utilized for groundwater storage is represented by the aquifer storage coefficient (S), a unitless
factor, which is multiplied by the total volume change to derive the change in groundwater in storage. Based
on work completed for the GSP, S is estimated to be 7 percent.

F Monitoring Network Module

G PMA Module