The Gardena Willows Wetland Preserve occupies 13.6 acres (55,000 m2) of land owned by the City of Gardena, in Los Angeles County, California. The preserve is the last intact remnant of the former Dominguez Slough, an important vernal marsh that once covered as much as 400 acres (1,600,000 m2) of this area, known as the South Bay region of Los Angeles County. The preserve has 9.4 acres (38,000 m2) of wetland and 4.2 acres (17,000 m2) of upland. The wetlands have a natural depression where water remains for such a significant time that plants and animals not adapted to water and saturated soils cannot survive. The upland, which remains dry outside of the rainy season, supports plants which thrive with these drier conditions. The slough is a part of the Dominguez Watershed, 96% of which is no