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se~ 2 <br />~asP 5 <br />In reference to the c3~artt~el repair, the reach of channels highlighted on Map 51A, <br />formerly called No. Per. Rev. 82-1-1, will be graded as needed. Any excess <br />material will be bladed up into the work area and then regraded to blerrl in with <br />the PYlCt1TY~ topography. For example, Area 51 repair eracluditg the ends, could <br />*~» T'p excavating approximately 1500 yd~ fran the c3iannel which would then be <br />spread over the work area, it would result in a rise in elevation of <br />app**~Y~+~tely 0.03 ft. which is insignificant to the postinininq topography. <br />In reference to Area 41, the drainage channel will be constructed as shown on Map <br />51A. ZYre fiction will involve removir-g topsoil fran the work area and then <br />excavating a ~T~~++~tely 70,000 CSt of material to form the drainage channel. <br />This material will be hauled to the west errl of Area 51 for disposal. 'ihe <br />reconstruction will result in decreasing the drainage gradient fr® over 403 to <br />less than 243. 4he side slope (3 horizontal: 1 vertical) of the drainage will <br />be regraded so that machinery can operate safely. Upon Dcx[q~letion of the <br />drainage reconstruction, the sideslopes will be topsoiled and seeded with the <br />rangeland seed mixtise and wntour furrowed. <br />An aooe~.,s road has been bladed into the Area 51 West channel repair area. <br />Rewnstruction of PG 31-1 will rc~n„ro sane excavation of regraded spoil. <br />n r*Y+Y~+++ately 6500 C& of material will be removed and ~+ ~ +Prtly disposed of <br />in the Area 51 West pit. 7.he maviimTm slope of the new channel flowline will be <br />253. Side slopes of the channel aryl the drainage inmiediately adjacent to the <br />channel will be graded to a 3:1 slope. The design criteria for this particular <br />channel is detailed within Appendix I B; Area 51 Channel Design and <br />• Specifications. <br />After a given ~~+an*+P~ has been prepared, a filter blanket will be constzcted on <br />the bottom and sides of the channel per the specification given in Appendix I. <br />After the blanket has been~~installed, the riprap will be placed per the <br />specification given In Apperd?Y I. After the blanket has been installed, the <br />riprap will be placed per the specification given in Appendix I. <br />Zhe rock initially used as riprap for same of the channels has passed the <br />specifications as indicated in the Appendix I-A report. However, experience has <br />shown the material is not suitable. 'Ihe formerly used riprap has been replaced <br />with durable rock which has a specific gravity of at least 2.5. his rock will <br />be used for the riprap in the channel construction project. <br />Upon ca~}~letion of the riprappirg, the work area and side slopes will be graded <br />so that the area blends in with the slsrauidirg topography. After this, topsoil <br />will be redistributed over the area. Zhe replaced topsoil will be seeded with <br />the appropriate seed mixture and Donlan- furrows will be inscribed. <br />In reference to Area 51 Fast, a plan far repairing the channel has been submitted <br />and is contained in Appendix I. A review of old pit maps reveals that the <br />section of channel needing repair has never been mined. 4he only activity that <br />occurred was stripping of topsoil fran the area in order to provide a buffer zone <br />far the pit and overburden stockpile No. 1 construction. ZYrerefore, the mining <br />has not resulted in a charge in topography for the area. Because of this, <br />Colorado Yampa Ccal Cot[q~arty has reevaluated the need for cannel repair. <br />• <br />- 52 - Revised 03/22/91 <br />