Biology Reference
In-Depth Information
patchwork of orange and pink ponds should all be converted to tidal marsh,
or a mix of wetland types and shallows, project planners decided to phase
in conversions at different times. Not only would this ease impacts on the
avian species that frequent the ponds in their current state (by shifting
them gently into new and improved habitats over decades) but it would
also give managers time to experiment with different restoration ap-
proaches, monitor results, and adjust their plans accordingly. If all the
ruddy ducks suddenly ceased over-wintering in Eden Landing, if mercury
levels spiked in the Alviso Slough food web, or if a critical flood control
levee started to erode, the project would have the flexibility to adapt.
The main thrust of the project is biological. Everyone wants to see
enough tidal wetlands around the bay to recover native Clapper Rails and
Harvest Mice, and enough dry patches around the wetland edge for Snowy
Plovers to nest. They want to see verdant new swaths of marsh vegetation
and new supplies of plankton, algae, and other fish food to bolster the eco-
logical functions of the bay's marshlands. But the project must also sustain
existing bird populations; keep levees strong enough to protect local urban
communities from flooding; and provide trails, scenery, and shoreline rec-
reation for the residents of the Bay Area.
Here, nothing could be further from the guerrilla restorations of earlier
eras, which involved little more than a well-placed stick of dynamite.
Though salt ponds retain more original wetland features than long-tilled
farm fields behind dikes—aerial photos reveal branching slough channels
beneath their crystalline salt crusts—there's much more to do on many of
the ponds than just reconnect them with the bay.
Michelle Orr, an engineer, has worked on restoring more than 30,000
acres of bay wetlands in her 15-year career with the consulting firm Philip
Williams & Associates, but she says the South Bay salt ponds are her “most
highly engineered” project. Her team's blueprints detail every tide gate and
culvert flap, every lowered berm and heightened levee, and every intake
and outlet canal. They map out which ponds will get deeper and which
shallower, and which will one day grow a carpet of salt-loving vegetation.
In some ponds, they specify new islands, to be scraped off the pond bot-
tom and piled up into circular and linear shapes—bird biologists want to
see which shape attracts the most nesters. For another pond, they've de-
signed a specialized gate using stacked fiberboards light enough for two
people to move, so that they can either allow tides in or keep floods out.
The seeds of this grand project go back decades. Ponds owned first
by Leslie Salt, then later by Cargill, have been battlegrounds for as long as
the restoration game has been played. When the
Habitat Goals
report
threw down the gauntlet in 1999, calling for 100,000 acres of tidal marsh
around the bay, Steve Ritchie remembers Cargill's public relations person
Jill Singleton looking him hard in the eye and saying: “We're not going to
