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Use of the site for agriculture has eliminated most natural vegetation. The site consists of abandoned agricultural fields and non-native grassland (CYA property and the triangular property), active agricultural fields (Brocchini property),and wetland drainages(Little Johns Creek and un-named irrigation ditch). Non- native annual grasses and other weeds dominate most of the CYA and triangular properties, as well as peripheries of the Brocchini property, totaling 136 acres. Non-native grasslands are used by many mannal and bird species for foraging and breeding. The Brocchini property has been used most recently for the cultivation of onions(Allium cepa). In the past it has been used to grow alfalfa(Medicago sativus)and likely other crops. At the time of the survey (September 23, 1999), the property consisted only of the cut stubble. of the cultivated crop. Generally, areas that are systematically disked can still provide habitat for rodents, which in turn can be used by raptors. . Two drainages are located on or immediately adjacent to the study area: Little Johns Creek and agricultural drainage ditch. The North Branch of the South Fork of Little Johns Creek is a perennial drainage that flows toward the west along the boundary between the Brocchini property and the existing landfill. The creek is constrained within a steep-sided channel from which the vegetation and accumulated sediment is periodically removed for flood control purposes. The drainage conveys heavy flows up to six feet above the channel bed during winter and spring. During the dry season,flows are less than one foot deep on average. The source of dry season flows may be largely agricultural irrigation runoff. Vegetation within the channel forms a continuous band of wetland and aquatic vegetation, but because of flood control maintenance activities, trees, shrubs, or riparian canopy are mostly absent. On the upper banks, the vegetation is a sparse cover of weedy and non-native species. This description of vegetation could be considered ruderal habitat. Ruderal habitat is that from which the native vegetation has been completely removed by grading, cultivation,or other surface disturbances. The agricultural drainage ditch conveys runoff from fields to the east of Austin Road to Little Johns Creek. It is 360 feet in length and averages five feet wide. A stand of approximately 14 valley oak trees with sten diameters ranging in size from 4 to 24 inches borders the ditch. The understory consists of weedy non- native species and a large population of native aster (Aster radulinus). In addition to the 14 oak trees ' 1 adjacent to Drainage A, another 18 valley oaks(Quercus lobata)occur on the site, as shown on Figure F-1. These trees range from 8 to 71 inches diameter at breast height (dbh). Valley oaks are recognized as important elements of the historic landscape and provide valuable habitat for many species ofwiidlife. I i A"Native Oak Tree" is a valley oak with a trunk diameter ranging from 6 to 32 inches for a single-trunk tree, E or for a multi-trunk tree, greater than 8 inches; or an interior live oak, California live oak, or blue oak with a ; trunk diameter ranging from 4 to 32 inches for a single-trunk tree, or combined trunk diameter of greater than 6 inches for a multi-trunk tree. A"Heritage Oak Tree" is a native oak tree with a trunk diameter of 32 inches or greater. All diameters are measured at 4.5 feet above ground elevation. Removal of heritage trees and native oak trees must be in accordance with the County tree ordinance (County of San Joaquin Development Title, Chapter 9-1505). Under this regulation, native oaks are to be replaced at a ratio of three trees for each tree removed. For heritage oak trees,the replacement ratio is 5:1. As part of the proposed project,a reach of the North Branch of the South Fork of Little Johns Creek would I" be relocated along the northern and western boundaries of the existing landfill. The creek, associated wetlands,and upland habitat within the banks of the channel occupy approximately 4.5 acres, according to I the 1994 EI R,which relied on an underestirhation of the creek length (6,500 linear feet versus actual length ; of 7,600 linear feet). Within this project reach, the Corps has determined there are 2.895 acres of jurisdictional waters of the U. S., including 0.859 acres of jurisdiction wetlands,which would be filled as a result of this project. This fill was authorized by the Corps under Individual Permit No. 199400974 on May 12, 1997, with certain terms and conditions, including adherence to the Wetland Mitigation and Monitoring Plan for the Austin Road Landfill Expansion (Jones and Stokes, 1996). Implementation of these measures would ensure that habitat values provided by the recreated features would achieve or exceed"no net loss" „ of wetlands and aquatic habitat on the site, in terms of functions and value as well as acreage. Creation of these features would provide nearly 4:1 acreage replacement of on-site surface water features. These San Joaquin County GP-99-7, ZR-99-6, UP-99-17, ER-99-21City of Stockton Community Development Page 10