SR 06:242 - Laserfiche WebLink

area, and the Augustin Bernal Wilderness Park is situated % mile south of the study area. Approximately V2 mile east of the study area, Arroyo Valle and San Ramon Creek converge with several minor tributaries to form Arroyo de la Laguna, which passes east-to-west beneath Interstate 680 and flows south between Foothill Road and Interstate 680. The study area consists of gently to steeply sloping land ranging in elevation from 375 to 530 feet above mean sea level. A majority of the study area is used for livestock grazing. Two houses and associated outbuildings are present on the eastern portion of the property adjacent to Old Foothill Road. A paved road off Old Foothill Road crosses the northern portion of the property and connects to a private residence just outside of the western boundary of the study area. A barn and small corral are present in the southeastern corner of the site. Surrounding land uses include rural residential to the north and immediate west, suburban residential to the south and east, and largely undeveloped open space to the west. The City of Pleasanton' s Alviso Adobe Community Park lies on approximately 7 acres immediately east of the study area between Old Foothill Road and Foothill Road. Vegetation on site consists primarily of non-native annual grassland with scattered or clustered trees. Grassland on site is typical of the region and is largely comprised of non-native annual grasses such as soft chess (Bromus hordeaceous), ripgut brame (Bromus dia:ndrus), Mediterranean barley (Hordeum marinum ssp. gussoneanum), Medusa-head (Taeniatherum caput-medusae), and wild oats (Avenafatua). Non-native forbs such as field bindweed (Convolvulus arvensis), bull thistle (Cirsium vulgare), fiddle dock (Rumex pulcher), Italian thistle (Carduus pycnocephala), and yellow star thistle (Centaurea solstitialis) are also abundant. A small stand of the native purple needlegrass (Nassella pulchra) was noted near the southwestern corner of the site. Native forbs detected within grasslands on site include California blue-eyed grass (Sisyrinchium bellum), turkey mullein (Eremocarpus setigerus), Spanish clover (Lotus purshianus), and vinegar weed (Trichostema lanceolatum), all common species. Several ephemeral drainages cross the study area, flowing easterly and off of the property into culverts beneath Old Foothill Road. At the time of the present survey, all on-site drainages were dry. Several of the drainages exhibit scoured and incised channels with cobbles. Others consist of unincised swales with grassy bottoms or support freshwater marsh vegetation characteristic of wetlands. Wetland plant species observed within drainages on site include the native iris-leaved rush (Juncus xiphioides) and spreading rush (Juncus patens), as well as non-native species such as rabbitfoot grass (Polypogon monspeliensis), and bird foot trefoil (Lotus corniculatus). Scattered trees on site are mostly native species including coast live oak (Quercus agrifolia), valley oak (Quercus lobata), and California buckeye (Aesculus cali/ornica). A large California sycamore (Platanus racemosa) is located along the southernmost drainage, and is one of 72 (out of 156) trees identified as Heritage Trees within the study area (HortScienGe 2004). Native shrubs include coyote h.......h fUrf,...,..."-,......;.... ...;1..1,.."';,.\ ........r1 rn1con..... ........,lr {Tn.v;r>nAnM,lvnM ~;"nv<.;lrt.h"~\ .u...."n.nn nth",rco Ii. r1""n<"", patch of coyote brush scrub is present on the uphill slope just west of the study area. Planted trees including Monterey pine (Pinus radiata), Tasmanian blue gum (Eucalyptus globulus), olive (Olea europea), and black walnut (Juglans sp.) are also present near the residences. S:'ProJects.Equity Enterprise.\V?eportNJueDiligenceEquity 09202004.doc 2