The Goleta Slough is an area of estuary, tidal creeks, tidal marsh, and wetlands near Goleta, California, USA. It primarily consists of the filled and unfilled remnants of the historic inner Goleta Bay about 8 miles (13 km) west of Santa Barbara. The slough empties into the Pacific Ocean through an intermittently closed mouth at Goleta Beach County Park just east of the UCSB campus and Isla Vista. The slough drains the Goleta Valley and watershed, and receives the water of all of the major creeks in the Goleta area including the southern face of the Santa Ynez Mountains.
The Santa Barbara Airport has the largest border on the slough and contains the largest part of the slough. UCSB, Isla Vista, the City of Goleta and other unincorporated areas of the county, including the landward bluffs of More Mesa, surround and encompass the rest of the slough.
The Goleta Slough as it exists today is the result of two major historical events of the late 1800s and first half of the 20th century. The first was the heavy grazing by cattle on the surrounding foothills and mountainsides followed by wide ranging grassfires, heavy rains in 1861/62, and flooding which caused so much erosion and deposition of sediment in the mouths of the creeks emptying into Goleta Bay that most of the bay became silt-filled salt marsh in just a couple of years. The second event was the filling and conversion of the marsh and remaining bay into a military airbase during World War II. This filling was completed by the reduction of the rest of Mescalitan Island, which was used for fill for the airport and the surrounding area. The former location of Mescalitan island now contains a sewage treatment plant.
While no longer having a regularly navigable mouth, nor depths in most places suitable for anything except canoes, kayaks, and very small boats, the slough remains a very important area of vital wetlands, salt marsh, and estuarian creeks.
"The Goleta Slough wetlands ... are fragmented along the coast from More Mesa to UCSB Storke Campus". The Goleta Slough Ecological Reserve is administered by the Calif. Dept. of Fish and Game. The Slough contains approximately 430 acres (1.7 km²) of wetland habitat (including the 360 acre (1.5 km²) ecological reserve and at Storke Campus). The approximate historic area was 1,150 acres (4.7 km²).
"The primary function of the Ecological Reserve is to provide habitat for wildlife and a setting for educational and research activities. Public utility and transportation corridors traverse the wetlands, and airport runways, a sanitary treatment plant, a power generation station, and light industrial facilities are constructed on filled portions of the marsh."
The Slough is fed by a watershed area of 45 square miles (117 km²).
279 species of birds have been observed at Goleta Slough; of these 121 were water-associated, including 20 species of special status.
Benthic invertebrates species composition is characterized by low diversity and densities. Three species of polychaetes and bivalves are identified. The epifaunal invertebrates that are abundant included the lined shore crab, yellow shore crab, and California horn snail.
November 1993 insect surveys conducted with a fine mesh seine or aquarium dip nets at the mouth and the back portion of the slough yielded 11 species; major taxonomic groups were bugs, damselflies, mayflies, beetles, caddisflies, butterflies and flies.
1986/87 trapping and visual surveys at the Storke Campus Wetlands identified two species of mice, one vole, one amphibian, and two species of reptiles. 1996 report identified the southwestern pond turtle in Atascadero Creek from surveys in 1982 and 1994. The 1996 report also identified three special status species from a 1983 survey of the Ecological Reserve: pallid bat, American badger, and San Diego black-tailed jackrabbit. Ten species of mammals were identified in 1970 survey of the main portion of the slough.
A 1996 report identified 20 special status species from various surveys (dates not specified): California Brown Pelican, southern bald eagle, peregrine falcon, snowy plover, common loon, American white pelican, double-crested cormorant, White-faced Ibis, Fulvous Whistling Duck, harlequin duck, northern harrier, golden eagle, osprey, long-billed curlew, California gull, elegant tern, and black skimmer. Those with specified dates included Belding's Savannah Sparrow (1994), and California horned lark (1995).