In the late summer very low flows are realized; moreover, in the late summer, which is toward the end of the dry season, the waters appear murky green, and much of the creek consists of a chain of stagnant pools. No noticeable odors emanate from this stream [citation needed]. Concrete and rock reinforcements are present all along the creekbed in much of the stream. The creek receives surface runoff from open space and residential land use. A fairly rich but narrow corridor of riparianvegetation appears along much of the middle reach creek bed, including cattails, numerous tree species, and a variety of herbaceous plants.[2] The creek flows at considerable force during the rainy season (November to March), and once a week in the summer water is released from a private reservoir upstream located next to Old Blackhawk Road.
The headwaters of Sycamore Creek rise on Mount Diablo, a protected nature reserve. This scenic upper reach has some Miocenefossil-bearing formations;[3] moreover, the upper headwaters reach is habitat for numerous rare species and endangered species including several serpentineendemics. Much of the middle-reach 5 miles (8 km) of Sycamore Creek reveal limited potential for hazardous materials contamination, as the developments abutting the stream bed consist of a country club, residential development and rural land use.
^United States Geological Survey, 7.5 Minute Diablo, California Topographic Quadrangle Map, (1953, photo revised 1968 and 1973), U.S. Government Printing Office, Washington DC
^Environmental Site Assessment for the Cameo Crest Subdivision, Danville, California, Earth Metrics Incorporated, July 18, 1989
