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Southern Santa Barbara County Coastal Watersheds Subregion
Watersheds and Wetlands in the Southern Santa Barbara subregion Watersheds: South Coast Hydrologic Unit Rincon Creek Franklin Creek Goleta Slough (Atascadero, San Jose, Las Vegas, San Pedro, Carneros, Tecolotito Creeks) Devereux Creek Gaviota Coast Creeks Wetlands: Carpinteria Salt Marsh Goleta Slough Devereux Slough: The coastal creeks and watersheds of southern Santa Barbara County are associated with the south facing Santa Ynez Mountains. These coastal watersheds and associated wetlands are unique in the context of southern California since they are located in an ecotonal area, where the northern and southern California biological provinces meet. The subregion is the northernmost boundary for many species of southern California. Restoration plans are currently being implemented in the three major wetlands of the subregion, Carpinteria Salt Marsh, Devereux Slough and Goleta Slough. The major concerns within the subregion are the preservation and restoration of wetland habitat, the protection of native species diversity, and addressing water quality concerns. Key issues for this subregion include: Preservation and/or restoration of steelhead habitat and removal of fish passage barriers. The sub-watershed encompasses 6,600 acres, and includes the tributaries of Santa Monica and Franklin Creeks (and a smaller unnamed drainage to the west of Santa Monica Creek). Carpinteria Marsh is situated in a context of residential development. Both Santa Monica and Franklin Creeks are tidally influenced through the marsh to the Pacific Coast Highway. The Carpinteria Salt Marsh is one of the most important wetlands in this subregion. The marsh is typically tidally influenced, but a barrier bar forms some years at the ocean inlet. The bar is then mechanically breached to maintain year round tidal flushing. At least 190 bird species, 37 fish species, 11 mammal species, 5 herpetofauna species, and over 100 invertebrate species have been observed, collected, or reported from Carpinteria Salt Marsh. The marsh is the northwestern geographic limit for many species (e.g., Estero Seepweed, Shoregrass, Belding's Savannah Sparrow, and Light-footed Clapper Rail). Water quality that drains to the marsh is impaired from pesticides, siltation, nutrients, and urban run-off. Non-native predators, typical of suburbanized watersheds, continue to be a threat to nesting birds and other wildlife. The watershed is in poor condition for steelhead passage; there remain many barriers and culverts in the upper part of this watershed. Goleta Slough The Goleta watershed encompasses 45 square miles. The tributaries of the watershed include Tecolotito, Carneros and Atascadero Creeks. The Goleta Slough includes 430 acres of an approximate historic acreage of 1,150, and is almost entirely surrounded by urban development, some of which extends into the wetlands. In 1996, 279 species were identified at Goleta Slough of which 121 species were water-associated, including 20 species of special status. In a 1994, 117 pairs of Belding's Savannah sparrows were observed nesting in the slough. 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. Continued sediment deposition is reducing the tidal prism. Due to limited buffer areas along the perimeter of the wetlands, wildlife is disturbed by highway traffic and activities in the developed areas. Several creeks within the watershed provide habitat suitable for southern steelhead restoration, but there remain several flood control dams, diversion dams, and culverts that prevent passage. Water diversions, small berms at the mouth of most creeks, and excess sediment have been noted in several creeks that could support a steelhead run. Devereux Creek The southern part of the Gaviota Coast includes the Devereux Creek watershed. The watershed area encompasses 2330 acres. Devereux Slough is located on the West Campus of the University of California at Santa Barbara. The approximate wetland habitat acreage is 70. Historically, the slough is estimated to have been approximately 2 to 3 times its present size. The slough is tidally influenced only during short periods in the winter. A beach berm forms at the mouth of the slough during drier months. Biological inventories have identified 290 species associated with the slough and Coal Oil Point Reserve of which 118 are water-associated, including 15 species of special status. The white-faced ibis was recorded as nesting. Sediment loading is reducing the total size of the slough. Continued residential development in the watershed may increase contamination of runoff and sediment entering the slough. Exotic plant species are displacing native plants and altering the habitats. Gaviota Coast Creeks The importance of this coastal stretch of southern California is reflected in the fact that the area between Coal Oil Point and Point Sal comprises only 15% of Southern California’s coast yet holds approximately 50% of its remaining rural coastline. This area includes relatively healthy coastal watersheds and wetlands because of the general lack of urban and suburban development. The main coastal ecosystems and watersheds on Vandenberg Air Force Base (VAFB) include the Santa Ynez River and the San Antonio Creek. These coastal ecosystems remain important nurseries to the sea, and are important to the health and integrity of the marine system of the Southern California Bight. VAFB is located in a transitional ecological region that lies at the northern and southern distributional limits of many plant and animal species. The base provides habitat for many special-status species, including federal- and state-listed threatened and endangered, proposed listed, and candidate plant and animal species as well as species of special concern. Recently, 14 major vegetation and habitat types were described and mapped on the base. More than 850 plant species, 53 mammal species, 315 bird species (115 breeding), 17 reptile species, and 10 amphibian species are found in these habitat types. The Santa Ynez River and San Antonio Creek are two major drainages, each with associated riparian and wetland habitats. Closely related to these habitats are adjacent transitional and upland habitats. Coastal marsh and lagoon habitats occur near the mouths of these two bodies of water where they drain into the Pacific Ocean. This variety in habitat types, in a relatively small area, provides the setting for a large diversity of plant and wildlife species. The Santa Ynez River is the largest watercourse on VAFB. A 400-acre lagoon, ringed with tidal wetlands and mudflats, lies behind the sand bar that forms at the river mouth during the summer months. Salt and freshwater marshes are also part of this wetland complex. The river once sustained an abundant wild southern steelhead run. The San Antonio Creek drainage extends from northeast of the town of Los Alamos to the San Antonio lagoon at the Pacific Ocean. Land uses in the Los Alamos valley upstream of VAFB are agricultural and include field crops, vineyards, and grazing lands. In the upper watershed, the vegetation community changes from intermittent riparian to coast live oak and valley oak. Upland habitats along San Antonio Creek include coastal sage scrub, coastal dune scrub, and nonnative grassland. Other vegetation includes nonnative grasses, shrubby scrub, disturbed roadside vegetation, and agricultural fields. The habitats adjacent to San Antonio Creek are considered wetlands, and are either willow riparian woodland or freshwater marsh habitat. Most of the vegetation found in these areas consists of facultative or obligate wetland species. The San Antonio Lagoon also includes freshwater and coastal brackish marsh habitats, which occur along with coastal strand habitat. The diversity of fauna in this area may be attributed to the variety of habitat types along and adjacent to San Antonio Creek. Willow riparian woodland supports a wide variety of birds, due to the cover, foraging habitat, breeding and nesting habitat, and perch sites provided by the willow woodland. In addition, several fish, reptile, amphibian, and mammal species use the upland and riparian habitats associated with San Antonio Creek for residence and migration corridors. Although VAFB contains extensive biological resources, disturbance from human activities such as agriculture, cattle grazing, groundwater withdrawal, road and other development, and exotic species introductions have resulted in the degradation of native upland and wetland species. Impacts of these disturbances have been noted in many parts of the base, including San Antonio Creek and the El Rancho Road Project area. The disturbances have resulted in changes in the creek’s flow regime and shifts in vegetation types.
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