Birds are expanding their range across the bay… growing in population.
That was the good news trumpeted in a recent frontpage story in the San Jose MercuryNews, on the heels of scientific reports about the progress of the fiveyearold South Bay Salt Pond Restoration Project. If the historic effort to turn 15,000 acres of former industrial salt ponds back into wetlands is a success, thousands of marshdependent birds will be returning to the lands of Don Edwards San Francisco Bay National Wildlife Refuge.
But what about the shorebirds and waterfowl that have come to inhabit the levees and open waters of the manmade salt ponds? What’s to become of the western snowy plovers, marbled godwits, ruddy ducks, scaups and gadwalls now that ponds are being restored to tidal marsh?
The restoration project is designed to provide habitat for them, toobut on a smaller footprint, made possible by cuttingedge design, highend technology, and intensive monitoring and management by refuge staff.
Industrial salt ponds around San Francisco Bay date to the 1850s; some remain in operation. The production process is fairly passive: Water is let in from the bay and allowed to course through a series of evaporation ponds, progressively increasing in salinity until it reaches a final, crystallizer pond, where the salt is harvested. The result has been the creation of an extensive network of ponds and levees where marsh once was. Over the decades, shorebirds and waterfowl came to migrate and live on the open pond waters and dry levees. Many of them arrived from California’s Central Valley after land there was drained for agriculture.
When the plan was developed to acquire the salt ponds as refuge land and restore them to marsh, a portion of the land was set aside to accommodate shorebirds and waterfowl. That meant designing a mix of open water and dry habitat on smaller acreage and intensively managing the new ponds with sophisticated equipment.
The first managed pond, known as SF2, near Palo Alto, was unveiled in September 2010, in a ceremony keynoted by Sen. Dianne Feinstein, a champion of the restoration project. What Feinstein and others saw that day was a designed landscape of open water, manmade islands and dry pan, bordered by levees with large weirs and gated culverts to regulate water levels. They also saw features along the main levee designed for public access, including a walking trail, viewing platforms and interpretive displays.
Now, biologists are monitoring Pond SF2 for bird population counts, nesting success and water quality.
We’re already seeing great use of the pond by willets, least sandpipers, dunlins and other shorebirds, says Cheryl Strong, wildlife biologist for Don Edwards San Francisco Bay Refuge. And we’re also seeing lots of waterfowl, like northern shovelers and northern pintails.
This fall, construction is scheduled to begin on similarly designed ponds outside the refuge’s Environmental Education Center in Alviso.
Managed ponds like these require a lot of work: adjusting weirs and culverts for water levels and doing regular levee maintenance, says refuge manager Eric Mruz. But it’s worth the effort if we can provide habitat for birds that don’t have many other places to go.
Doug Cordell is a public affairs officer at San Francisco Bay National Wildlife Refuge Complex.