Carbonera Creek

at Monterey Bay at Santa Cruz [USGS Quadrangle Map, U.S. Government Printing Office, Washington, DC, 1980).]

The perennial Carbonera Creek has a watershed of 7.4 square miles. ["Environmental Impact Report for the Scotts Valley Redevelopment Area", Earth Metrics Incorporated, State of California Clearinghouse Report 7888 (1990)] The West Branch of Carbonera Creek is a total of 1.4 miles in length and passes under Vine Hill Road. The West Branch continues under Scotts Valley Drive and the State Route 17/Granite Creek Interchange through a series of box culverts. The West Branch joins the main branch of Carbonera Creek immediately south of the State Route 17/Granite Creek Interchange. Carbonera Creek is the major surface water hydrological feature in Scotts Valley, running across the western portion of the Santa's Village site and through the center of town.

Topography and geology

Elevations in the Carbonera Creek watershed vary from about 500 feet above sea level on the valley floor to 1123 feet at the highest ridge.

Precipitation and flow rates

The average annual precipitation in the Carbonera Creek watershed ranges from 85 to 120 centimeters per year, ninety percent of this falling between November and April. Carbonera Creek flows at an average of 0.8 to 1.0 cubic feet per second. Lower Bean Creek has a high average flow of 3.0 cubic feet per second. However, the flow in both creeks greatly depends on the season; in fact, flows in these creeks typically drop dramatically during the dry summer season.

Ecology

Riparian woodland vegetation is located Carbonera Creek and its tributaries. The 1990 Earth Metrics EIR identifies broadleaf deciduous trees as dominating this habitat and are able to survive because of the year-round presence of fresh water. Examples of such trees present in the riparian zone include California bay laurel ("Umbellularia californica"), boxelder ("Acer negundo"), California Sycamore ("Platanus racemosa"), black cottonwood ("Populus trichocarpa"), Bigleaf maple ("Acer macrophyllum"), white alder ("Alnus rhombifolia"), and various willows (Salix spp.). Invasive root systems of these trees are important in erosion control and their dense canopy provides food and shelter for a variety of birds and mammals, yielding high habitat value. The lush cover afforded by this habitat also provides wildlife with a suitable environment for breeding. Additional vegetation found along creek banks includes California blackberry ("Rubus vitifolius"), Himalaya blackberry (Rubus procerus), poison oak ("Rhus diversiloba"), baltic rush ("Juncus balticus"), redwood sorrel ("Oxalis oregana"), snowberry ("Symphoricarpos rivularis"), Coastal wood fern ("Dryopteris arguta"), and other herbaceous species and decaying vegetation.

The plant community Northern coastal scrub also exists in the Carbonera Creek catchment basin. This community is scattered throughout the basin, typically situated on windy, exposed sites with shallow, rocky soils. The community is dominated by California sagebrush ("Artemisia californica"); toyon ("Heteromeles arbutifolia"); "coyote brush ("Baccharis pilularis"; California yerba santa ("Eriodictyon californicum"); and manzanita (Arctostaphylos spp.)

Within the Carbonera Creek watershed is one of the three known Maritime Coast Range Ponderosa Pine forests, a rare assemblage of vegetation narrowly restricted to sandy, infertile Zayante soils formed over Santa Margarita Sandstone. This habitat is only found in coastal Santa Cruz County and is found in a part of the Carbonera Creek catchment in the southwestern part of the City of Scotts Valley on the slopes of Mount Hermon, extending to the south. The surface soil and subsoil drain very rapidly and do not retain enough water to support local climax species such as Coast redwood or Douglas fir. The Ponderosa Pine ("Pinus ponderosa") withstands the stresses of this xeric habitat and typifies the open plant community, which also supports rare species of flora such as the Bonny Doon manzanita (also called the silver-leaved manzanita) ("Arctostaphylos silvicola") and the endangered Ben Lomond wallflower ("Erysimum teretifolium"). There are two Federally listed endangered species of insects within this sparse forest.

Aquatic species include Steelhead trout ("Onchorhynchus gairdneri", formerly Salmo gairdneri) and Chinook salmon ("Onchorhynchus tshawytscha"), which migrate up the San Lorenzo River and its tributaries, including Carbonera Creek. For instance, these migratory fish species spawn in Carbonera Creek gravels downstream of the Santa's Village Area.

ee also

*Branciforte Creek
*Endangered arthropod
*Ohlone
*Scotts Valley, California
*Zayante Creek

References