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A spikerush vernal marsh at the California Department's of Fish and Game's Tolay Creek area.
Photo by Peter Baye
Sacramento River rock rip rap.
Photo by Joe Silveira, U.S. Fish and Wildlife Service
Wetlands are our "natural sponges," with the ability to absorb heavy rains, flood waters, and excess sediment, and to filter pollutants. Yet nearly 90 percent of the wetlands that once fringed the Estuary have been destroyed—to build ports, airports, roads, bridges, and residential or commercial developments—or were put behind levees and filled for agriculture. These activities removed habitat for young fish, which use tidal marshes as nursery areas for rearing and growing, and species like the California clapper rail and salt marsh harvest mouse (both now endangered), the black rail, salt marsh song sparrow, and many others. Many seasonal wetlands throughout the Estuary watershed, including vernal pools, a unique type of wetland that provides habitat for the California tiger salamander, a federally endangered species, and for native bees, insects, and tiny crustaceans, have also been filled for development.
Streams throughout the Estuary watershed have been filled, channelized, piped under ground, and built on top of, and their important ecological connections with the Estuary broken. Rivers have been riprapped and straightened, in misguided attempts to reduce erosion and flooding. These activities have altered natural hydrology and destroyed floodplains, often resulting in increased flooding as rivers can no longer spread out and their waters infiltrate the ground during high flows. Loss of riparian vegetation along rivers and streams has resulted in less habitat for migratory songbirds—which use these corridors as stopover points during their journeys—as well as for resident birds while riprap has destroyed the soft river banks that bank swallows (a threatened species in California) need to burrow into.
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