Bollinger Canyon Creek

Bollinger Canyon Creek begins as a number of ephemeral streams emitting from a horst valley, Bollinger Canyon, in the highest reaches of the Berkeley Hills, in California's Inner Coast Ranges. == Geography ==

Bollinger Creek exhibits a character similar to many other streams in Central California. It is vegetated with California mixed evergreen forest, chaparral and open grasslands, habitats typical of the East Bay region. Many of its tributaries only carry water during storms. The region surrounding the creek has a cool-summer mediterranean climate which generally keeps temperatures mild. Due to its proximity to the Pacific Ocean, the creek and its watershed are often inundated with fog. Virtually the entirety of the creek's course upstream from San Ramon, California is undeveloped, with ranching and open space making up the majority of land use. == Ecology ==

and Bollinger Creek, with Rocky Ridge in the background (December, 19th, 2021) ; Bollinger Creek runs through a belt of oak and laurel trees with Las Trampas Ridge and Mount Diablo in the background. (May 24th, 2022) Because much of its course is undeveloped, Bollinger Creek is an important habitat for local wildlife. Much of the land in the watershed is forested and rugged, providing habitat for a variety of wildlife species. Black-tailed deer, Coyote and boar are seen regularly. A wide variety of raptors, among them Red-shouldered hawks and Great horned owls reside in the watershed, particularly on the steep rock outcrops on Las Trampas Ridge, as well as turkey vultures. Trout Population Bollinger Canyon Creek is unique in that it retains a population of Coastal rainbow trout which have been extirpated from much of the San Francisco Bay watershed through development and the installation of migration barriers like dams. It is speculated that this population is of hatchery origin and escaped from a stocked pond during a flood event. Regardless of their origin, the most recent survey of trout distribution in the region showed that rainbow trout were successfully reproducing in Bollinger Creek. The lack of development in Bollinger Canyon and the quality of the habitat found in the area has likely aided the trouts' establishment in the creek. The total population is unknown, and it is unclear how the trout fared during the severe droughts between 2012 and 2020. == References ==