- Basin Name
- Petaluma Valley
- Basin Number
- SGMA Basin Priority
- Critically Overdrafted
- Developing a GSP
- DWR Region & POC
North Central Region Office
- Number of Wells
- Hydrologic Region Name
- San Francisco
- Marin, Sonoma
Located in California’s San Francisco Bay hydrologic region, the Petaluma Valley is 46,043 acres in size. This High priority basin is home to an estimated 49,858 people (2010 value), which have been at a rate of . Petaluma Valley is a(n) basin with approximately 1131 wells, of which approximately 31 are water supply wells. Groundwater accounts for approximately 57 percent of the basin’s water supply.
1982: Bulletin 118-4 Evaluation of Ground Water Resources Sonoma County Volume 3: Petaluma Valley
2014: Basin Prioritization note:
Widespread and serious nitrate contamination affecting shallow wells in the upland area NW of Petaluma. Generally poor quality GW south of Petaluma. Potential for seawater intrusion in tidal reaches. Increasing MTBE contamination.(B-118 unpublished data).
2017: Hydrology chapter, Davidon/Scott Ranch GPA, Rezoning, and 1222.001 VTM Revised Draft EIR, Impact Sciences, Inc.
2018: Basin Prioritization note: 1) CASGEM/WDL/GWIDS: Stable hydrographs. Source: DWR 2) 1) Sources of chloride in the north San Francisco Bay area aquifers include seawater intrusion, thermal water, and dissolved minerals from marine and volcanic rocks. The valleys most affected by large chloride concentrations are the Petaluma, the Sonoma, and the Napa, in which seawater intrusion caused by excessive ground-water withdrawals has been the primary source (fig. 110). Reduced withdrawals and increased surface-water imports have helped alleviate the salinity problem. Source: USGS HA730-B
Basin boundary modification request with Wilson Grove Formation Highlands 1-059 pending