Stevens Creek (California) - Habitat and Conservation

Habitat and Conservation

Stevens Creek is one of the prime steelhead trout (Oncorhynchus mykiss) habitats within the county. However, there are significant barriers for this anadromous fish. In a 1994 study, the Santa Clara Valley Water District (SCVWD) found fish ladders at the Central Expressway and Highway 101 often had insufficient flow and/or were clogged with debris and sediment. In addition, the drop structure at L’Avenida Avenue was impassable in all five years of the study. In August, 2003 the Stevens & Permanente Creeks Watershed Council was officially formed to support stewardship of the watersheds. The SCVWD’s Fish and Aquatic Habitat Collaborative Effort (FAHCE), has recommended removal of the Denil-type fish ladders at Fremont Avenue, Evelyn Avenue, and Moffett Boulevard which tend to clog with debris and are now classified as partial barriers by the California Department of Fish and Game (CDFG). Adjacent to the fish ladder at Moffett Boulevard is a concrete drop structure built in the 1980s which is another obstacle to salmonid passage. The existing concrete-lined channel extending further downstream to Highway 101 (a distance of 450 feet) is flat and low flows cross it as a thin sheet of water over the concrete bottom. At least 6-inch depth of flow is required for adequate fish passage.

The Western Burrowing Owl (Athene cunicularia) nests at Shoreline Park near the mouth of Stevens Creek. In 2008, Mountain View evicted a pair of burrowing owls so that it could sell a parcel of land to Google to build a hotel at Shoreline Boulevard and Charleston Road. Eviction of the owls is controversial because the birds regularly reuse burrows for years, and there is no requirement that suitable new habitat be found for the owls. Despite being listed in 1979 as a Species of Special Concern (a pre-listing category under the Endangered Species Act) by the California Department of Fish and Game, California's population declined 60% from the 1980s to the early 90's, and continues to decline at roughly 8% per year. In 1994, the U.S. Fish and Wildlife Service nominated the Western Burrowing Owl as a Federal Category 2 candidate for listing as endangered or threatened, but loss of habitat continues due to development of the flat, grassy lands used by the owl. According to The Institute for Bird Populations at Point Reyes, there has been a 50 percent decline in burrowing owl populations in the Bay Area in the last 10 to 15 years. Their status protects them from disturbance during nesting season or killing at any time, but does not guarantee them a permanent home, as outside of breeding season, owls can be evicted from their homes. A 1992-93 survey reported no breeding burrowing owls in Napa, Marin, and San Francisco counties, and only a few in San Mateo and Sonoma. The Santa Clara County population is declining and restricted to a few breeding locations, leaving only Alameda, Contra Costa, and Solano counties as the remnant breeding range.