Wetlands Restoration

Passage One

More than 95% of the historic tidal marshes have been leveed and filled since 1850 with associated losses in fish and wildlife habitat. The flow of freshwater into the estuary has been greatly reduced by water diversions largely to support irrigated agriculture. Harbor and channel dredging has changed both the dredged and disposal sites and altered water flow patterns and salinity. Contaminants enter the estuary in municipal and industrial sewage, and urban and agricultural runoff. Introduced exotic species continue to change the Bay's biota by altering its food webs. All of these changes have had marked effects onthe estuary's biological resources, particularly well documented by declines in abundance of fish species (San Francisco Estuary Project Management Committee 1994). Furthermore, this loss of the estuary's wetlands has placed increased importance on the remaining 125 km² of wetlands that continue to be threatened by development, erosion, pollution, and rising sea level.

Changes in the quantity, timing, and quality of fresh water flowing into the Delta and Bay, as a result of diversion via pumps within the Delta, is implicated in declines of fish species both because of physical removal of young fish by the pumps as well as habitat changes resulting from changing flow patterns and salinity distributions. . . .

^{Source: United States Geological Surveyâ— San Francisco Bay and Delta http://sfbay.wr.usgs.gov/access/yearbook.html}

Passage Two

The bay also is the site of the most ambitious wetland restoration program in the country. Through a confederation of federal and state agencies and private groups, tens of thousands of acres of salt ponds and drained farmland in the south and north bays are being restored to salt marsh, freshwater marsh and wild uplands.

But the estuary is still beleaguered, a fact that's measured in its fisheries, or lack of them. Delta smelt, a small, native brackish-water fish that inhabits the upper reaches of the bay and the Sacramento-San Joaquin River Delta, is at all-time lows. This is significant because the smelt is considered the prime indicator for the estuary's biological health.

"Actually, the entire complex of bay and delta fish species is suffering, " said Tina Swanson, the senior scientist for the Bay Institute in Novato.

Factors for the decline include agricultural chemicals from the Central Valley, runoff from urban streets and invasive nonnative species, Swanson said. But reduced freshwater inflow may be the biggest problem, she said.

During the Clinton years, Swanson noted, less Sacramento River water was diverted for Central Valley agriculture and Southern California cities. Instead, it was sent down the delta and bay. This was accomplished through the passage of the 1992 Central Valley Improvement Act and the creation of CalFed, a joint state and federal agency empowered to divide the water among agricultural, urban and environmental interests.

The extra water flushed juvenile fish past the destructive diversion pumps in the delta and created a large, biologically rich brackish zone that sustained plankton, fish and crustaceans.

But under the Bush administration, the U.S. Bureau of Reclamation, which controls the tap on Shasta and Folsom Dams, implemented new rules for allocating bay and delta flows.

The amount of water going through the estuary was reduced, and the amount of water pumped south was increased. The result, Swanson said, is collapsing fisheries in the bay and delta.

Bureau of Reclamation spokesman Jeff McCracken acknowledged the bureau is pumping more water south than it did in the late 1990s but said the agency was honoring its environmental obligations.

"We are meeting standards set by the U.S. Environmental Protection Agency, the U.S. Fish and Wildlife Service and the National Marine Fisheries Service, " he said.

^{Source: Martin, Glen. “Despite strides, Bay Area has mixed record on freshwater Pollution reduction, Hetch Hetchy delivery offset by invasive species, runoff from streets.” June 1, 2005. http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2005/06/01/MNGHQD1INN1.DTL. ©2005 San Francisco Chronicle.}