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Page 3 Jim Monroe 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. WETLAND DELINEATION RESULTS Patterson Run 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 culvert under the California Aqueduct. At this location, the channel is 56 feet across, which narruws to 30 feet across and is deeply incised, with steep banks on either side. It appears that the channel had recently been dredged at this end of the drainage, to remove excess sediment to improve flood control. Due to the presence of cattails (Typho sp.) in the dredge spoils deposited at the top of the banks, it is assumed this channel was dominated by catta'u. Remnant wetland vegetation on either side of the channel include cattails and rushes (Juncus sp.) located from the OHW to 3 feet up the bank. The steep banks were dominated by upland vegetation including annual rye grass (Lolium multij7orum), wild oats (Avena folua)., fiddleneck (Ams,'nckia menziesh), bromes (Bromus diandrus, Bromus hordoceus), and California bur clover(Medicago polymorphs). As Patterson Run meanders across the site, the channel narrows to 15 to 25 feet, and becomes less utcised. The channel is dominated by cattails, curly dock (Rumex crispus), and tushes, with an occasional willow (Salix sp.). The terrain becomes more flat, and the banks are 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 serriola), rabbitsfoot grass (Polvpagon monspeliensis), and Bermuda grass (Cvnodon dactylon) 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 (Xanthium strumorium), Italian thistle (Carduus pycnocephalus), willowherb (Epilobium brachycarpum), alkali mallow (Malvella leproso), 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 sedimtnt deposits. The soils were clay loam, with moderately abundant mottles. All of the wetland criteria were met, indicating that Patterson Run qualified as a wetland area RMI R 1 1 0 1 M t l Ti A% A..t Ip ftN] AIIOCAt. Igo•