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Page 3 Jim Mo^.roe Patterson Pass Business Park A comprehensive delineation of the site was conducted on March 17, 1998. Five separate potential wetland areas were identified; Patterson Run (Sheet 3), Area C (Sheet 3), Drainage A (Sheet 3), Drainage B (Sheet 4), and a pond (Sheet 4). Each of these areas will be discussed separately. 1 WETLAND DELDiEA77ON RESULTS Patterson Run 1 Patterson Run is an intermittent ephemeral drainage, varying in width from 14 to 56 feet; which meanders from southwest to northeast across the site. This drainage flows from a culven under the California Aqueduct. At this location, the channel is 56 feet across. which narrows to 30 feet across and is deeply i.-tcised, with steep banks on either side. it appears that the channel had recently been dredged at this end of the drainage, to remove excess 1 sediment to improve flood control. Due to the presence of cattails (Tvpho sp.) in the dredbe spoils deposited at the top of the banks, it is assumed this channel was dominated by catta'i<. Remnant wetland vegetation on either side of the channel include cattails and rushes (Jurcus 1 sp.) located from the OIiW to 3 feet up the bank The steep banks were dominated by upland vegetation including annual rye grass (Lolium multij7orum), wild oats (Avena fatua), fiddleneck: (Amsinckla menziesi), bromes (Bromus diandrus, Bron7us rordaceus), and California bur clover(Medicago polymorpho). As Patterson Run meanders across the site, the channel narrows to 15 to 25 feet, and becomes less incised. The channel is dominated by cattails, curly dock (Rumex crispus), and rushes, vrith an occasional willow (Salix sp.). The terrain becomes more flat, and the banks are t dominated by creeping wild rye (Leymus triticoides). Agricultural practices such as discing and oat cultivation are conducted up to the edge of the banks of the drainage on either side. At the northern end of the drainage, willows dominate the overstory, and the channel is dominated by creeping wild rye, rush (Juncus effusus), and cattails. Creeping wild rye, curly dock:, prickly lettuce (Lactuca serriolo), rabbitsfoot grass (Polvpogon monspeliensis), and Bermuda grass (Cvnodon doctylon) grow along the sides of the channel. The top of the banks are characteristic transitional areas, with mixed upland and wetland vegetation such as prickly lettuce, wild oats; western nettles (Urtica sp.), cocklebur (Xanthfum strumarium), Italian thistle (Carduu.s pycnocephalus), willowherb (Epilobium brachycarpum), alkali mallow (Mohrllo leprosa), Jimsonweed (Datura stramonium), and rye grass. When this area of Patterson Run was delineated on November 21 1997, the bottom of the channel had deep soil cracks and the top 6 inches of the soil profile was saturated, providing a positive indicator for wetland hydrology. Vegetation showed evidence of flowing water and sediment deposits. The soils were clay loatn, with moderately abundant mottles. All of the wetland criteria were met, indicating that Patterson Run qualified as a wetland area- RM I reaKM[ RI \nl Fa l 111 .1\AI.t,\I, \ , 1 ] tCt �AItOV Ai, I .c.