Mowry Slough

Mowry Slough is a tidal channel and salt marsh complex in the East Bay, San Francisco Bay Area of California, in Alameda County, California. The slough lies near Fremont, California, Newark, California, and the Don Edwards San Francisco Bay National Wildlife Refuge, connecting to the San Francisco Bay and adjacent salt ponds. It forms part of a larger estuarine network influencing regional San Francisco Bay estuary processes and urban coastal habitats.

Geography and Course

Mowry Slough runs through the southern margins of the San Francisco Peninsula salt marshes adjacent to the Don Edwards San Francisco Bay National Wildlife Refuge, bordering Fremont, California, Newark, California, and the CDFW Eden Landing areas before discharging into the central basin of San Francisco Bay. The slough system interfaces with levees, restored wetlands near the South Bay Salt Pond Restoration Project, and infrastructure such as the Dumbarton Bridge corridor, the State Route 84 (California) alignment, and local drainage networks. Its channelization and connections include tidal inlets that exchange with tributaries influenced by runoff from Alameda Creek watershed features and urban runoff near Union City, California and Hayward, California.

Ecology and Wildlife

Mowry Slough supports salt marsh habitats that provide nursery functions for estuarine fishes such as species important to California Department of Fish and Wildlife monitoring, shorebirds monitored by Point Blue Conservation Science, and federally recognized species under the Endangered Species Act including migratory populations tracked by the U.S. Fish and Wildlife Service. Vegetation zones include stands of Spartina alterniflora where invasive cordgrass concerns intersect with native marsh restoration efforts by organizations like the San Francisco Estuary Institute and the U.S. Geological Survey. The slough provides feeding and roosting for species documented by the Audubon Society, California Academy of Sciences, and birding groups active in the San Francisco Bay National Wildlife Refuge Complex. Aquatic invertebrate communities and eelgrass patches of the estuary are studied by researchers from University of California, Berkeley, Stanford University, and San Jose State University for their roles in supporting food webs utilized by California least tern and salt marsh harvest mouse conservation programs.

History and Human Use

Historically, the marshes around the slough were utilized by indigenous communities such as the Ohlone people prior to contact into the Spanish colonization of the Americas era and subsequent Mexican California land grants like those influencing regional land use. During the 19th and 20th centuries, industrial salt production by companies including the historical Cargill Salt operations transformed adjacent ponds; federal and state agencies later engaged in restoration via the South Bay Salt Pond Restoration Project in cooperation with NGOs such as the California Coastal Conservancy and the San Francisco Bay Conservation and Development Commission. Urban expansion in Fremont, California and transportation projects, including rail lines of the Southern Pacific Railroad and interstate alignments for Interstate 880, led to levee construction and altered tidal exchange analogous to modifications elsewhere in the San Francisco Estuary. Archaeological surveys coordinated with the California Historical Resources Commission have documented cultural resources and historical land use patterns in the slough corridor.

Hydrology and Environmental Issues

Hydrologic dynamics of the slough are governed by semidiurnal tides of the San Francisco Bay, freshwater inputs from the Alameda Creek system, and managed pond operations influenced by entities such as the U.S. Army Corps of Engineers and local water districts including the Alameda County Flood Control and Water Conservation District. Environmental concerns have included subsidence from historical peat oxidation, contamination from legacy industrial discharges monitored by the Regional Water Quality Control Board and the Environmental Protection Agency, and invasive species management overseen by the California Invasive Plant Council. Sea level rise projections examined by NOAA and the California Coastal Commission inform adaptation planning, while sediment supply and marsh resilience are topics of study by the San Francisco Estuary Institute and USGS researchers in collaboration with National Oceanic and Atmospheric Administration programs.

Recreation and Access

Public access to the slough and adjacent trails is coordinated through the Don Edwards San Francisco Bay National Wildlife Refuge, the Bay Trail network, and local park systems including Coyote Hills Regional Park and shoreline units near Newark, California. Birdwatching groups like the Golden Gate Audubon Society organize visits, and kayak tours organized by regional outfitters and environmental NGOs provide opportunities to view marsh ecology while complying with protections for sensitive species enforced by the U.S. Fish and Wildlife Service and refuge managers. Interpretive programs and volunteer restoration events are run by partners including the South Bay Salt Pond Restoration Project and the California Department of Parks and Recreation to balance recreation with conservation.

Category:San Francisco Bay Category:Estuaries of California