Laserfiche WebLink
• frc~ the SIDIl~b7P II model, the peak stage is at 59.06 ft. (Elev. <br />6613.06). ~e principal spillway can adequately handle the peak <br />di.~rharge rate of 18.88 cfs at a depth of flow of 1.86 ft. (see Table <br />8). At the peak stage (59.06 ft.) there is still appmY~~tely 1.0 <br />ft. of freeboard before the porri would reach a ma~riTrnim stage of 60.00 <br />ft., which is a conservative estimate aryl within the rer.~~irements for <br />a spillway to handle the runoff from a 25-year, 24-hr storm event. <br />Zherefore, the principal spillway at inlet elevation of 6611.20 will <br />also serve as the emergency spillway. In addition to handling this <br />runoff, the detention time is adequate to have a peak effluent <br />sediment oonoentlation of 0.0 mg/1 with 0.0 tons of ecriimant <br />di c~-teamed and 100.0 percent basin trap efficiency (see Table 7, <br />Storm Event Summary Port). <br />~e Wadge Impau~nent (No. 002) will remain as a rnrmanant incised <br />• impo~uxtnent after mining to o®ipliment the pcstmina lard use. 'IIze <br />pond will provide a dependable source of water for livestock and <br />wildlife. Appendix 7-10, Tab 7, the Pord Abarrlormient Plan section of <br />Tab 13, and the Propoeed Decision and Findings of Ccunpliance Docimiestt <br />far the secorrl renewal of Seneca II Mine Permit C-80-005 (11/20/92), <br />contain discussions ~rta;n;m t0 the permanence of this facility. <br />Zhe prq.~osed tra.,aarw.,r postmiaie Wadge Ittq~ourrknent (No. 002) i.s shown <br />on Exhibit 7-8A. <br />i <br />7-6a-6 Revised 12/10/92 <br />