History of the Wetlands

The San Francisco Bay was a valley until eight to ten thousand years ago, when the sea level rose and the land was inundated with ocean water. When the sea level finally stopped rising rapidly about 4,000 years ago, sediment began to build up and create the Bay’s tidal marshes. At their height, the Bay’s tidal wetlands covered 800 square kilometers and were home to diverse species and the Muwekma-Ohlone Native Americans, who used the Bay’s resources sustainably. Conversely, the Europeans settlers who arrived later had purely economic motives, exploiting and degrading the area. Intense environmental pressures also came with the beginning of the Gold Rush in 1848. In some areas, manmade marshes created by sediment from hydraulic mining replaced natural wetlands. Yerba Buena and Mission Bay were filled in to accommodate the thousands of spectators moving to the Bay. Shockingly, the state sold marshlands for $1 an acre during this period.

The Moffett Air Field was constructed on the South Bay Marshes in 1932. Next came the creation of Treasure Island, the Alameda Naval Air Station, Mills Field (which became the San Francisco International Airport), and the Hamilton Army Field. All of these projects either required the development or filling in of parts of the Bay. By 1950, 90% of the Bay’s wetlands had been destroyed. Despite the degraded state of the environment, there were still plans to continue to fill in parts of the Bay for different purposes. It wasn’t until the Army Corps of Engineers drew up a map that predicted that the Bay would become a small canal by 2020 if such extreme development persisted that people began to realize that protection and restoration was necessary. Catherine Kerr, Sylvia McLaughlin, and Ester Gulick created Save the Bay in 1961. The organization put forth massive organized efforts to stop developers from encroaching on even more on the Bay’s wetlands. Other large-scale restoration projects started in 1969. Efforts to return the Bay back to a healthier, more sustainable state continue today, such as the South Bay Salt Pond Restoration Project.