Two environmental concerns in the San Francisco Bay area are the loss of wetlands and the need for safe disposal of dredging sediments. The San Francisco Bay has lost more than 90 percent of its wetlands to housing, airports, industrial parks, farms, and sanitary landfills. These wetlands had held shoreline erosion in check by regulating the flow of water into the bay. In addition, wet­lands had purified the water entering the bay, provided critical habitat for wildlife (in­cluding a large stopover area for migratory birds), and performed many other valuable

Shipping channels, marinas, and ports in the bay gradually fill in with sediment and must be dredged periodically to prevent ships from running aground. But what can tie done with the tons and tons of sediment that are removed from the bay floor? In the past, this material was dumped either in other parts of the bay or in the Pacific Ocean. Neither location was satisfactory because of the harmful effects on estuarine and oceanic wildlife. In­creasingly, environmental organizations and regulatory agencies demanded an alternative disposal site that would not have so many harmful environmental effects.

In 1991 an environmental consulting firm and a real estate developer jointly announced the Montezuma Wetland Project, a proposal to restore wetlands in San Francisco Bay using the dredging sediments from the bay. The project, now under way, involves the restoration of approximately 809 hectares (2,000 acres) near the mouth of the Sacra­mento River. It is the largest private wet­lands restoration endeavor ever undertaken in the western United States. The cost of the restoration is funded entirely by dredging disposal fees.

The original wetlands around the bay were drained and diked in the 1880s; since then the land has subsided several feet below high-tide levels. In the restoration project, approximately 13.8 to 18.3 million cubic meters (15 to 20 million cubic yards) of sedi­ment are being transported and dumped at the site. The sediments will be engineered to resemble the channels and land contours of natural tidal and seasonal wetlands. Then native plants, birds, fish, and small mammals, many of which are endangered or threatened species, will be re introduced to the site.

The Montezuma Wetlands Project, which is strongly supported by many environmental organizations and local states and federal agencies, will take at least a decade to com­plete. Once the site is restored, it will be­come a wildlife refuge under the permanent protection of either the federal government or an appropriate environmental organization.