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GSA Interactive Map

New!The GSA Interactive Map has been updated with the 2016 Bulletin 118 Groundwater Basin Boundary Modifications.

New! LOCAL AGENCIES AND GSAs: Please review your posted GSA area and make boundary revisions accordingly, as the basin boundary modifications may have affected your intended GSA management area. If necessary, please submit the following to DWR: (1) a detailed written explanation of your desired GSA boundary revision; (2) an updated hard-copy map(s) showing revised 2016 groundwater basin boundaries, desired GSA management areas, and local agency service areas; and (3) corresponding GIS shapefiles for desired GSA management areas. DWR will append this information to your posted notice.

This interactive map (below) shows the location of local agencies that have notified DWR of their intent to undertake sustainable groundwater management by deciding to become or form a GSA. The boundaries of the proposed GSA management areas are based on information submitted or approved by those agencies. While DWR makes every effort to provide accurate information, DWR has not reviewed all GSA boundary information contained in this map and makes no warranties as to the suitability of this map for any particular purpose. The GSA Formation Table should be referenced to determine the status of a local agency’s GSA formation notice. Not all GSA areas are shown on the map, as GIS shapefiles may not have been provided. Local agencies or GSAs should be consulted to determine parcel-level detail for proposed or exclusive GSA areas.

The GSA Interactive Map application includes the following layers that can be turned on/off (click the legend icon to show the layer functionality). The bolded layers indicate the layers that are turned on by default.

  • GSA Notice Submitted: The GSA boundaries reflect the area(s) of a basin(s) a local agency intends to manage, as described in the local agency’s posted notice. The darker color identifies those areas where multiple local agencies have indicated their intent to manage groundwater in the same portion of a groundwater basin(s). GSA overlap must be resolved before DWR will designate a local agency as an “Exclusive GSA.” (Water Code §10723.8)
  • Exclusive GSAs: These GSAs are designated as “Exclusive GSAs” because no other local agency submitted a conflicting notice within 90 days, or previous GSA formation overlap has been resolved. Exclusivity within a basin only applies to the area within a local agency’s service area.
  • New!Bulletin 118 Groundwater Basins (2016): Please download the modified 2016 groundwater basins here and form (or revise) GSA management areas within those 2016 basins.
  • New!Bulletin 118 2016 Changed Areas: GSA management areas may need to be revised if a GSA boundary intersects with a basin boundary that has been modified. GSA areas can only be located within the boundaries of the 2016 basins, and some posted GSA notices may now extend into an adjacent or newly-formed basin, or extend into non-basin area.
  • Adjudications: Water Code §10720.8 provides a list of adjudicated areas.
  • Counties: The boundaries of California’s 58 counties are shown.
  • Exclusive Local Agencies: Water Code §10723(c) provides a list of local agencies created by statute to manage groundwater within their respective statutory boundaries. These exclusive local agencies must still decide to form a GSA and notify DWR of their intent to undertake sustainable groundwater management.
  • Bulletin 118 Groundwater Basins (2003): These are the old basin boundaries. Do not form GSAs using these boundaries.
  • CASGEM Prioritization: Basins listed as high, medium, low, or very-low priority are shown. Basin prioritization is based on Bulletin 118 (2003) boundaries and will be updated in spring 2017 to reflect the 2016 basin boundaries. (Water Code §10722.4)

If you have questions related to GSAs or have comments related to the interactive map please contact Mark Nordberg at The GSA Interactive Map was last updated on February 10, 2016.