Groundwater Monitoring and Hydrographs

Groundwater wells throughout the Sacramento region are monitored regularly to track groundwater levels:

  • The California Department of Water Resources (DWR) and Sacramento County Water Agency have maintained a network of wells throughout Sacramento County. Water level records for some of the wells date back to the 1950s. Long-term hydrographs from those wells track the groundwater elevation trends during the underlying aquifer system’s major development period.
  • Additionally, multiple-completion or nested monitoring wells and well clusters have been installed within the basin and can monitor more than one discrete depth at the same overall location.
  • Since spring 2012, SGA has maintained a DWR-approved California Statewide Groundwater Elevation Monitoring (CASGEM) Network of more than 40 wells. All of those wells are monitored on a minimum of a semi-annual basis. Since the region recognized the onset of drought conditions in early 2013, a subset of those wells has been monitored more frequently to ensure that undesirable results do not occur in the basin.

Long-Term Hydrographs

Hydrographs provide detailed data about annual variations in water levels due to seasonal precipitation and pumping, on top of longer water level variations due to water use and climate. The North Area Basin is divided in three sub-basins: Western Area, Central Area and Eastern Area.

  • Western Area: Bound by the Sacramento River on the west and extends east to approximately the boundary between Natomas Central Mutual Water Company and Rio Linda/Elverta Community Water District. This area is served almost exclusively by surface water.
  • Central Area: Bound roughly on the west by the boundary between Natomas Central Mutual Water Company and Rio Linda/Elverta Community Water District and to the east by a line running approximately along San Juan Avenue. This area currently uses a combination of surface water and groundwater, but historically relied predominantly on groundwater.
  • Eastern Area: Extends roughly east of San Juan Avenue to the American River, which is the eastern edge of the basin. This area has historically relied primarily on surface water.

Learn more:

The red points on each of the hydrographs represents the Spring (or annual high) groundwater level measurement.