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Biological Resources, MOND &ASSOCIATES Impacts and Mitigations Tracy Facility Expansion Site mined areas and reseeding this area with native grasses and forbs. The post excavation elevation in this area would be approximately 45-55 feet below existing grade. Final slope contours would be graded as shown in Appendix A,Figures 2 and 3. 5.3.2 CORRAL HOLLOW CREEK CROSSING To access the north side of Corral Hollow Creek a temporary crossing of this-creek would be installed at approximately station 2+00 during the first two years that the site is mined. With the exception of this creek crossing, the Corral Hollow Creek channel will be completely protected from all mining activities. The creek crossing would be approximately 30 feet wide and would consist of annual temporary installations of three parallel 48-inch diameter x 40-foot long corrugated steel culverts that would be covered with 3 feet of native material. These culverts would be installed no earlier that February 15th and removed no later than October 31St each year,but in no event would they be installed while the creek is flowing. These culverts would only carry unseasonal storm water flows in Corral Hollow Creek that occurred during the dry season. A streambed alteration agreement would be obtained from CDFG pursuant to Section 1603 of the Fish and Game Code prior to the installation of these.culverts. Similarly, verification for use of Nationwide Permit 14 (road crossings)would be obtained from the U.S. Army Corps of Engineers(Corps)prior to installation of these culverts. After mining and reclamation of the north portion of the project site, the road crossing would be permanently abandoned. 5.3.3 EXCAVATION OF THE SOUTH SITE Upon completion of mining activities north of Corral Hollow Creek, excavation of the portion of the site south of this creek would commence in the year 2001. All mining and reclamation activities would be completed over a 6-year period in accordance with the schedule presented in Table 1. The excavation depths south of Corral Hollow Creek would be variable and are i estimated to be from 10 to 80 vertical feet below the existing ground elevation. Excavation of the area south of Corral Hollow Creek would be similar to the north side of this creek. Since the existing grade elevation south of the creek is lower than north of the creek(due to previously mined conditions of this portion of the site and the general lay of the land), lean clays encountered during excavation would be used to construct a compacted clay berm along Corral Hollow Creek. This berm would be constructed to prohibit large storm event flows from entering into the southern mined area. Lean clays would also be used for final slope construction. Reclamation of the south side would include spreading previously stripped topsoil over the mined site. Mined areas would be re-seeded to native grasses and forbs and allowed to revert to an annual grassland habitat. All reclamation of the south site would be completed by the year 2006. 5