Biological Resources Management

Sweetwater Authority's EGS Department is responsible for government regulations, legislative issues and grants, as they relate to the environment. EGS is also responsible for watershed protection, monitoring and environmental compliance.

Wildlife Habitats


Sweetwater owns some of San Diego's most valuable wildlife habitat, found in the natural areas surrounding its reservoirs. Reservoir lands are home to several threatened or endangered species, including the least Bell's vireo, the arroyo southwestern toad, and the California gnatcatcher.

Sweetwater Authority has worked closely with regulators for more than 2 decades to create and manage sustainable vireo habitat. The Authority creates new habitat on its property within a formerly disturbed sand mining site. Then, after biologists have confirmed that the vireos are using the new habitat areas, identified patches within the reservoir bottom can be cleared. By 2010, the Authority will provide and maintain 123 acres of habitat, compared to the 93 acres of habitat present in 1988.

Habitat Management Program


Sweetwater's Habitat Management Program has proven its benefit to the vireos. The numbers of vireos have been stable and have even increased. Vireos have also moved into the area previously used for sand mining.

To establish habitat, Sweetwater Authority has transplanted fully-grown willow trees, propagated thousands of other native plants, and removed invasive plants from the areas. To assure long-term health of the habitat, Sweetwater Authority will monitor the vireo population and its habitat, remove invasive non-native plant species, and will restore managed habitat areas as needed.

Long-Term Management


Long-term reservoir management activities to protect water quality include routine vegetation removal along the reservoir bottom, sediment control, and maintenance of established patrol roads.

Phase I Clearing Area


  • Cleared: 167.0 acres
  • Remaining: 10.0 acres

Phase II Clearing Area


  • Cleared: 13.5 acres
  • Remaining: 19.1acres
Restoration Area 16.0 acres

To learn more about Sweetwater Authority’s Habitat Management Program, please call 619-409-6814.