Foster City, California, was created in the 1960s on former tidal marshland near San Mateo, overlaid with an engineered landfill of sand and shell dredged from San Francisco Bay.
The lands were once tidal wetlands sitting around mean sea level which were were dried out in the 19th century using dikes and levees to keep out the tidal flows. The reclaimed lands became Brewer Island and converted to agricultural use for grazing dairy cattle, and evaporation pools for salt production.
When developer T Jack Foster selected the site for a new master planned city, the soft tideland, sea-level elevation, and earthquake risk, presented engineering challenges to be resolved. In 1961, a hydraulic fill operation used 18 million cubic yards of sand dredged from the sea floor at San Bruno Shoals, north of San Francisco Airport. This was pumped out and spread over the existing soft terrain to create a firm base for the new city and raise the land level by some 4 to 5 feet to provide a drainage gradient. A purpose-made drainage lagoon system with pumps was designed to ensure that the community could handle severe storms without risk of water inundation and flooding.