The California State Coastal Conservancy and US Army Corps of Engineers are restoring the Hamilton Army Airfield and adjacent State Lands Commission property to tidal and seasonal wetlands.
Once part of an extensive tidal wetlands area in San Francisco Bay, this area of low lying land was diked and then converted to an airfield in 1930.
The primary goal of the seasonal wetlands restoration is to provide 200 acres of sustainable roosting and foraging habitat for shorebirds. Being highly sensitive to hydrology and invasion by non-native plants, seasonal wetlands are complex wetlands to restore. Together, the seasonal and tidal wetlands will evolve to provide a complete sustainable habitat mosaic for coastal wildlife.
ESA provided the conceptual design and assisted in preparation of engineering design drawings for this 900-acre tidal and seasonal wetland restoration. The restoration approach employed a combination of engineering solutions to address site constraints and reliance on natural sedimentation and vegetation colonization to re-establish natural tidal wetland functions.
ESA completed 2D hydrodynamic and sediment transport modeling, flood modeling, wave analysis, and other engineering analyses to support the design. The design includes a “habitat levee” that relies on gentle slopes and vegetation instead of rock armoring for erosion control.
According to the U.S. Fish and Wildlife Service, more than half of America’s historic wetlands have been lost or disturbed as a result of human intervention. In San Francisco Bay, this number is even higher, at more than 90 percent.