Smith River Plain

Source: CA DWR

Smith River Plain


  • Basin Name
  • Smith River Plain
  • Basin Number
  • 1-001
  • SGMA Basin Priority
  • Very Low
  • Critically Overdrafted
  • No
  • Hydrologic Region Name
  • North Coast
  • Counties
  • Del Norte
  • Adjacent Basins
  • No items found


Located in California’s North Coast Hydrologic Region hydrologic region, the Smith River Plain is 40,434 acres in size. This Very Low priority basin is home to an estimated 24,604 people (2010 value), which have been at a rate of 12.31.

Smith River Plain is a(n) basin with approximately 1346 wells, of which approximately 19 are water supply wells. Groundwater accounts for approximately 64.81 percent of the basin’s water supply.

Source: CA DWR
Source: CA DWR

Basin Notes

1970: A Study of the Smith River Basin and Plain, California Department of Water Resources

2003: Bulletin 118 basin description

2016: Basin prioritization comment – Groundwater levels: 1)CASGEM/WDL/GWIDS: Stable hydrographs. Source: DWR 2) Generally, groundwater level data show a seasonal fluctuation of approximate five to 15 feet for normal and dry years. Source:  Draft Environmental Assessment, Smith River Rancheria Water Resource Development Project, U.S. Bureau of Reclamation (USBR)

Salt intrusion:  Salinity monitoring found salt water intrusion to reach 7.65 km upstream of the mouth during summer low flow conditions. Comparatively the salt water intrusion was minimal during the winter season indicating the majority of the lower Smith River estuary is freshwater during the winter months. (Saline intrusion most likely due to seasonal variations and not from pumping groundwater). Source: Distribution of Juvenile Salmonids and Seasonally Available Aquatic Habitats Within the Lower Smith River Basin and Estuary, Del Norte County, California, Smith River Alliance, 2015

2018 Basin Prioritization (Dec 2018): priority changed from medium to very low

2019: Basin prioritization: Very low. Boundary modification pending.

GSA Information

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