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B. Diversions and Conveyance of Overland Flow -Rule 4.05.3 <br />There is no diversion of overland flow or shallow ground water from undisturbed azeas above <br />disturbed areas at the Colowyo Mine at the present time. Eazlier approved diversions have been <br />mined through as the East Pit advanced to the south. <br />C. Stream Channel Diversions =Rule 4.05.4 <br />Minor realignments and changes in permanent stream channels profiles aze permitted within <br />reclaimed mined and excess spoil fill azeas. Pre-mining and post-mining alignments are similar. <br />However, profiles deviate more mazkedly. The most significant.example is Streeter Gulch. <br />Streeter Gulch is an ephemeral drainage (PAP, page 2.04.7-27). It was (pre-mining) asteep- <br />sided, 200-foot deep (neaz the. mouth) incised draw (PAP, Map 11). Initial box cut material for <br />mining south of the Gulch (Draw) (PAP, page 206-3) was placed neaz the mouth, fast as an <br />experimental practice and Iater recognized as excess sporl(overburden} fiII. Upstream <br />topography was, as a result, necessazily modified. The pre-mining 16,000-foot-long Streeter <br />Gulch profile ranged from 5% near the lower end, increasing to 12.5 % for the upper 1800 feet <br />(measurements, Map 18, PAP). The post-mining profile is 30% for the fast 1000 feet up the face <br />of the. Streeter Spoil fill, and thence approximately 4 % across the approved post-mining . <br />topography of reclaimed land (measurements; Map 14, PAP).. Such diversions are designed, and <br />certified liy a registered piofessional'engineer, to.accommodate.the 100-year designstorm [Rule . <br />4.05.4(2)(a) and (b)]. These diversions comply with the requirements of Rules 4.05.3(1)(b) <br />through (f) (they aze in compliance with applicable statutes and regulations, are designed not to <br />increase flooding or otherwise endanger property or prtblic safety, are designed.to be. stable and' <br />not adversely impactto the hydrologic balance; and do not diverE water into underground mines)_ <br />Construcfion is still in progress: Riprap is used to control erosion. The channels are stable and <br />require infrequent maintenance [Rules 4.05.4(2)(a) and (4.05.4(4)(b)]. In smaller tributaries, <br />profiles have been altered to accommodate post-mining sides at lesser slopes (for stability) that , <br />original steepravine slopes. <br />D. Sedimentafion Control Measures, Ponds and Dischazge Structures -Rules 4.05.5, 6 & 7 <br />Ten. sediment ponds. are-irt place.as approved.by.the Diuision and treatdxsturbed area surFace <br />water runoff:.These are the Streeter Gulch, Work Area, Gulch A; Loadout; Stoker, Railway Loop, <br />Prospect, West Pit, East Taylor,. and Section 16 Ponds_ Designs for these ponds aze included in <br />Exhibit 7, and locations of the ponds aze shown on Maps 'I2 and 37. <br />October 21, 2002 26 <br />