Sacramento Valley – South American

Statistics

Basin Name

Basin Number

5-021.65

SGMA Basin Priority

High

Critically Overdrafted

Hydrologic Region Name

Counties

Sacramento

Adjacent Basins

San Joaquin Valley - Cosumnes 5-022.16, Sacramento Valley - North American 5-021.64, Sacramento Valley - Solano 5-021.66, Sacramento Valley - Yolo 5-021.67, Sacramento Valley - Northern Delta Subbasin (Proposed),

At-A-Glance

Located in California’s Sacramento River hydrologic region, the Sacramento Valley – South American is 248,403.37 acres in size. This High priority basin is home to an estimated 722,033 people (2010 value), which have been at a rate of 26.
Sacramento Valley – South American is a(n) basin with approximately 4301 wells, of which approximately 265 are water supply wells. Groundwater accounts for approximately 50 percent of the basin’s water supply.

Source: CA DWR

2003: Bulletin 118 basin description

2014: CASGEM basin prioritization – high. Comment from B118: Montgomery Watson (1997) listed seven sites within the subbasin with significant GW contamination. From Sac County GWMP: Overall decreasing GW level trend over past 50 years (~30ft).

2016: Basin boundary modification request by Omochumne-Hartnell Water District San Joaquin Valley – Cosumnes subbasin. Per DWR: This request was submitted as both a scientific internal and jurisdictional internal modification. However, the request did not provide necessary scientific information to meet basin boundary definition requirements, therefore it was evaluated solely as a jurisdictional modification. Based on Sacramento County comment the modification request was denied. Border change noted as part of Yolo County boundary modification.

Revised basin boundary description

Sacramento County GSP alternative proposal.

Analysis of basin conditions submitted to DWR.

2018: Draft basin priority – high. Comments: 1) CASGEM/WDL/GWIDS: Longterm hydrographs show groundwater level decline. Source: DWR 2) Sacramento Central Groundwater Authority Groundwater Elevation Monitoring Plan CASGEM monitoring plan (February 2012) states in that the intensive use of the groundwater basin has resulted in a general lowering of groundwater elevations near the center (or centroid) of the basin away from the sources of recharge.

Basin boundary modification request to create a new subbasin in the northern portion of the Delta involving the Solano subbasin 5-021.66 and Eastern San Joaquin Valley subbasin 5-022.01 pending with DWR.

Northern Delta Groundwater Sustainability Agency webpage on basin boundary modification.

2019: Basin boundary modification notices.