Santa Clara Valley – Niles Cone
Statistics
- Basin Name
- Santa Clara Valley – Niles Cone
- Basin Number
- 2-009.01
- SGMA Basin Priority
- Medium
- Critically Overdrafted
- No
- Hydrologic Region Name
- San Francisco Bay
- Counties
- Alameda
At-A-Glance
Located in California’s San Francisco Bay hydrologic region, the Santa Clara Valley – Niles Cone is 65,214 acres in size. This Medium priority basin is home to an estimated 323,119 people (2010 value). It has approximately 269 wells, of which approximately 28 are water supply wells. Groundwater accounts for approximately 33.40 percent of the basin’s water supply.
Basin Notes
2003: Bulletin 118 basin description
2014: Basin Prioritization notes: Saline water intrusion has increased landward and into deeper aquifers since first documented in the 1920’s.(B-118) GW Use based on B118-03 data. GW percentage is updated based on PubCom.
2016: Basin boundary modification with Santa Clara Valley – East Bay Plain 2-009.04
December 31– Existing Alternative to GSP submitted to DWR (approved)
2018: Draft basin prioritization comment – Declining groundwater levels and salt intrusion: East Bay Municipal Utility District service area: San Ramon, Richmond (between San Pablo Bay and Berkeley), Ygnacio and Clayton Valley, Castro Valley, and South East Bay Plain (Niles Cone borders East Bay Plain basin on south) basins. The basins have similar morphology and a Mediterranean climate. All are structural depressions formed by folding and faulting, all are filled with marine and alluvial sediments, and all are drained by streams that contain water at least part of the year. Seawater intrusion is common. Groundwater use in the East Bay Municipal Utility District service area is limited by several factors, including the effects of saltwater intrusion and contamination in shallow aquifers on groundwater quality and the availability of higher quality imported surface water. Groundwater is currently not used by East Bay Municipal Utility District for municipal supplies. Alameda County Water District provides retail water supplies to the cities of Fremont, Newark, and Union City. The district has implemented treatment of brackish groundwater to allow previously unused groundwater to be used as a potable water source (ACWD 2011, 2012). In 2003, the Alameda County Water District Newark Desalination Facility began to remove salts and other constituents from the Niles Cone subbasin groundwater that is subject to seawater intrusion using a reverse-osmosis process. Source: Long-Term Operation EIS, Chapter 7, pg 7-56, U.S. Bureau of Reclamation (USBR), 2015 2018 Final Basin Prioritization: Basin status is unchanged at medium priority.