8J Consent 2011 0404 - Laserfiche WebLink

Home

LEA ASSOCIATES, INC. CEQA INITIAL STUDY /MITIGATED NEGATIVE DECLARATION MARCH 1011 PREDA STREET PIPE BRIDGES UPGRADE SAN LEANDRO. CALIFORNIA Vegetation. The site is located at an existing sanitary sewer pipe crossing (i.e., two parallel sewer pipes and supporting steel truss pipe bridges) over San Leandro Creek and adjacent to Alder Creek Circle in San Leandro (Figures 1 and 2). The reach of San Leandro Creek immediately downstream of the bridges consists of a concrete - lined, trapezoidal flood control channel. At the time of the site visit. this reach of the channel was relatively dry (i.e.. several small shallow puddles from local urban runoff were present) and supported limited patches of herbaceous aquatic' vegetation that had become established where sediment had accumulated in the bed of the channel. The creek banks on either end of the bridge are steep and covered in dense vegetation, primarily blackberry (Rubus sp.) and English ivy (Hedera helix). At the southeastern corner of the bridge, blackberry growing on the nearby bank has spread onto the bridge structure, forming a dense impenetrable thicket. Portions of the ground surface not covered in blackberry support non - native annual grasses such as ripgut brome (Bromus diandrus), barley (Hordeum sp.), and wild oats (Avenafatua); and ruderal (i.e., weedy) forbs such as Italian thistle (Carduus pvcnocephalus), cheeseweed (Melva parviflora), poison hemlock (Corium maculantm), and wild radish (Raphanus saliva). A large, multi - branched arroyo willow (Salix lasiolepis) is present adjacent to the southeast end of the bridge and its canopy extends over the most of the southern bank. Several smaller arroyo willows grow within the creek channel, as well. Other tree species observed growing on the creek banks include blue elderberry (Sambucus mexicana) and silver wattle (Acacia dealbata). At the time of the September I site visit, the surface of San Leandro Creek under and downstream of the bridge was covered in duckweed (Lernna sp.). Upstream of the bridge, the water in the channel was stagnant and contained a substantial amount of algae. Hydrophytic plant species observed growing within and adjacent to the channel include horsetail (Equisetum sp.), willowherb (Epilohiunr sp.), smartweed (Polygonum sp.), and bulrush (Scirpus nricrocarpus). Wildlife. Wildlife observed on or in the vicinity of the site on September I included sixteen bird species: rock pigeon, mourning dove, white- throated swift, Anna's hummingbird, downy woodpecker. black phoebe, Pacific -slope flycatcher, western scrub -jay, Bewick's wren. American robin, northern mockingbird, cedar waxwing. Wilson's warbler. California towhee, black- headed grosbeak, and house finch'. With the exception of white- throated swift, Pacific -slope flycatcher. Wilson's warbler, and black- headed grosbeak, which were likely fall migrants passing through the area, all of these species are generalists that have adapted to human- modified landscapes. On August 6, LSA biologist Sean O'Brien observed a single western pond turtle (Actinemys marmorata) in the creek channel approximately 120 feet upstream of the project site near the existing railroad bridge. The observation of this species, a California Species of Special Concern, is somewhat noteworthy since the CNDDB contains no records of this species within the San Leandro USGS quadrangle and it is typically associated with less disturbed habitat conditions than those present in the immediate site vicinity. The site also provides habitat for other urban - adapted wildlife species such as arboreal salamander (Amides lugubris), Sierran treefrog (Pseudacris regilla), common garter snake (Thamnophis sirtalis), fox squirrel (Sciurus niger), northern raccoon (Procyon lotor), and striped skunk (Mephitis mephitis). Special- status Species. Based on a review of the CNDDB and observations during LSA's reconnaissance -level surveys, LSA identified 24 special- status species (9 plants and 15 animals) as I Scientific names of bird species are not provided in the text since common names are standardized in the American Ornithologists' Union Check -list of North American Birds (AOU 1998). P:1 EGI0801 \CEQA\Predn_FINAL_IS- MND.doc (0328/11) 19