White Slough

White Slough is located on the north side of Vallejo and is bisected by Highway 37. The southern basin currently serves as a critical flood control basin for that part of the city.

A Brief History of White Slough

Like much of the shoreline around the San Francisco Bay, White Slough was historically a tidal wetland. In the late 1800s, levees were built and the land within was drained and used for farming.

From the early 1930s until the late 1950s, the land north of what is now the intersection of Highway 37 and Sacramento Street was put to various uses, including an airport. Over time the airport deteriorated, the office and hangars disappeared, and swamp grass took root. From the 1950s to the late 1970s a levee holding back the Napa River failed several times. Finally, the U.S. Army Corps of Engineers deemed it too expensive to continue to repair, and the area returned to its natural tidal origins.

After the levee failure, the southern basin of White Slough became a stagnant body of water, cut off from the tides by undersized culverts. In 2002, the Corps of Engineers fit a large culvert built by CalTrans with automatic tide gates, allowing greater flow into that area of the Slough and increasing its effectiveness as an important flood control basin.

The Natural World of White Slough

Although surrounded by a busy urban landscape, the slough is critical for wildlife: open water provides habitat for waterfowl (such as the long-billed dowitchers at right) to forage, mudflats allow migrating shorebirds to feed, the islands are safe havens for resting shorebirds and provide nesting areas for ducks and terns. White Slough is part of the Napa Marsh, the largest brackish marsh in California. It contains such valuable habitat that the American Bird Conservancy has designated it a Globally Important Bird Area.

The northern part of White Slough is a protected wetland, home to endangered and threatened species such as the California clapper rail, California black rail, salt marsh harvest mouse and California red-legged frog.

The southern portion of White Slough is a 125-acre brackish marsh that acts as a detention basin for floodwaters from Austin Creek during the winter months. White Slough receives tidal flow from the Napa River and fluvial (river-produced) flow from Chabot Creek and Austin Creek.

Some bird visitors to White Slough include American avocets, black-bellied plovers, great blue herons, double-crested cormorants, barn swallows, California gulls, house finches, least sandpipers, gadwalls, marbled godwits, long-billed curlews, greater yellowlegs, red-winged blackbirds, western meadowlarks, willets and snowy egrets.