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In same ram, rills and gullies will be monitored rather than repaired. Zhe details of the monitoring 1 are further explained in Fri.bit 28. • Each year followuig spring runoff, a survey will be initiated to locate all rills and gullies. Monitoring of select rills and gullies will occur at this time as well. Repair will begin as soon as weather permits and will be completed by October 31. Part 3: Permanent Drainagewav Construction A deltnnstration has been made showing that gullyimg deeper than 9 inches is a natural ge®arphic process in the mine area. Zhe maps contained in Ddii.bit 28 show the approximate locations where gullying can be expected and where permanent drainageway construction will or has occurred. A demonstration has also been made which shows that the planned permanent drainageways are similar in density to those naturally occurring on disturbed sites. Zbpsoil will be removed from parmarwnt drainage channels prior to construction. 4he design of permanent channels and diversion ditches will follow the methods outlined in "Procedures for petorm;n;m peak Flows in Colorado" (SCS, 1977). • Diversion ditches will channel runoff directly to engineered pP*~++~*+Pr+* channels. Certain generalized guidelines may be outlined here. 'typically, the channels will be designed to aoo®mmdate the peak runoff flow fr®n the 10-year, 24-hour precipitation event. Normal antecedent moisture oorrlitions (AMC-II) will usually be as~•-~' for these calculations. Curve numbers (CN) will be assigned to the drainage area based on guidelines outlined in the SCS publication. If several distinct surface wrrlitions exist, then appropriate values will be assigned to each area and the total flows based on area-weighted calculations. Further details and examples of rnrmaTwnt dra]nageway construction can be fOUI1d within Fsdiibit 28, Rill aryl Gully Plan, of Permit C-81-071. • MIR Permit Renewal 780-129-3 Revised 03/20/91