Success Stories: Managed Ponds: South San Francisco Bay Salt Pond Restoration

L. Arriana Brand and Cheryl Strong

Dabbling ducks have increased in South Bay ponds.

With the transfer of over 15,000 acres to public ownership in 2003, the South Bay Salt Pond Restoration Project is the largest wetland restoration on the West Coast. An early goal in the long-term restoration plan was to reduce salinity in open ponds from their inherited toxic production concentrations to those of ambient Bay waters. The U.S. Geological Survey began monitoring birds and water quality from the start of the project and has documented increases in shorebirds and ducks as the restoration has proceeded. Examples include the 480-acre Island Ponds that were opened to tidal action in 2006. As salinity declined from 160 to less than 20 ppt, average numbers of dabbling ducks increased from zero in 2003 to over 4,000 birds at high tide on a given winter day in 2009. In the larger Alviso system and across the South Bay’s managed ponds, dabbling ducks such as Northern Shoveler increased substantially through winter 2010. The restoration project occurs within a designated area of Hemispheric Importance for migratory and wintering shorebirds such as Western Sandpipers. Further north, in the Eden Landing pond complex, small shorebirds during spring have increased from 10,000 to over 50,000 birds observed in monthly surveys, as water depths declined in former commercial salt ponds now maintained as seasonal wetlands. Numerous ponds are planned for enhancements or restoration to tidal marsh within a 50-year time horizon, and continued monitoring is critical to learn from successes or unexpected changes that can feed back into adaptive management in this extremely important area for birds within San Francisco Bay.