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III. Environmental Setting, Impacts,and Mitigations F. Vegetation and Wildlife Vegetation planted within the detention basins and adjacent to the rechannelized drainage structure should consist of herb,shrub,and tree species native to the area. For example, planted trees should be limited to the following species: valley oak,Fremont's cottonwood,California native sycamore, native willow species,California black walnut, box elder, and Oregon ash. Planted trees should be randomly spaced,by location and by species,to ensure maximum benefit to wildlife(i.e.,to avoid homogeneous stands in orderly rows), and should be planted at no greater than 50 foot intervals. The species' mix and densities of vegetation planted in the detention basin should be determined based on a study of vegetation present within the off-site CYA detention basin. This latter site should serve as a reference site to define appropriate densities and species' mix and to establish mitigation success criteria. (c) Once the CRRP is approved by all concerned agencies,the project proponent should implement the CRRP. The modified creek and associated vegetation should be protected through fencing of the currently proposed 15-foot nondevelopment setback buffer, extending from the edge of planted riparian vegetation to either side of the relocated channel. Fencing of the detention basin is currently proposed as part of the project. Clearing of vegetation within these areas shall be prohibited. Successful implementation of the suggested mitigation measures would reduce potential impacts to the Creek to less than significant levels(use of native species and monitoring and maintenance of mitigation lands is consistent with San Joaquin General Plan 2010). Implementation of measures(b)and(a) would ensure that habitat values provided by the recreated features would achieve,at a minimum,or exceed "no net loss" of watercourse habitat on the site,in terms of function and value as well as acreage. Impact F.2. Implementation of the proposed project may remove up to thirty-two valley oaks, averaging approximately thirty inches dbh. (SIGNIFICANT) The valley oak, a CNPS List 4 species,is identified as a significant resource in both the City of Stockton General Plan and San Joaquin County General Plan 2010. Removal of on-site oaks measuring 50 inches or greater in circumference at 24 inches above grade would also require a permit be obtained and replacement trees be planted pursuant to the City of Stockton's Heritage Tree Ordinance No. 007-90. Removal of these trees,therefore,would conflict with local policies 5 Design of the detention basin shall consider the needs and requirements of species planted as part of the rev„egetation plan. The detention basin should be slightly oversized to account for additional spatial requirements of the planted vegetation,and shall be designed to contain water throughout the majority of the year to meet these species edaphic requirements. Planting of freshwater wetland species, such as cattail and bulrush,within this basin would facilitate and expedite natural colonization of the basin. III.F.24