The Suisun Marsh Region, which encompasses more than 115,000 acres of wetland and upland habitats is of major importance to migrating and breeding waterfowl, shorebirds, and other waterbird species of the Pacific Flyway. The Marsh represents about 12% of all the remaining natural wetlands in California, yet water quality and species diversity have gradually declined in the past 25 years. These declines have occurred in the Marsh due to increases in water salinities as a result of freshwater diversion from the Sacramento and San Joaquin rivers, and the inability of property owners within the Marsh to receive and adequately distribute freshwater to promote suitable habitat for a variety of avian species. To improve brackish-water and freshwater exchange, and thus the Marsh's overall water quality and biodiversity, partners are altering the topography by deleveling fields and contouring pond bottoms, creating new circulation and drainage ditches, installing additional water-control structures, constructing islands, redirecting the flow of tidal and surface waters, and managing water levels.