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SAES can be found in Exhibit 7 of Volume 18 of the PAP. <br /> All disturbed area surface drainage in the South Taylor area will drain through sediment ponds; <br /> no SAES are approved in the South Taylor watershed (4.05.2(3)(b)(i)). Mixing of surface <br /> drainage with discharges from underground workings will not occur at these sites. <br /> B. Diversions and Conveyance of Overland Flow- Rule 4.05.3 <br /> The drainage and sediment control plan provides for temporary and permanent diversion of <br /> surface drainages within the permit area. A system of ditches, as shown on Maps 11 and 12 as <br /> well as Exhibit 7 of the PAP, convey runoff through disturbed areas and divert runoff from <br /> disturbed areas to sediment ponds. <br /> C. Stream Channel Diversions and Reconstruction - Rule 4.05.4 <br /> Diversions of perennial streams around mined areas is not a regular practice at the Mine. <br /> Reconstruction of channels is an important aspect of Colowyo's reclamation practices. <br /> Reconstructed channels are designed (and certified by a registered professional engineer) to <br /> accommodate the 100-year design storm event (Rule 4.05.4(2)(a) and (b)). The channels are <br /> designed not to increase flooding or otherwise endanger property or public safety and are <br /> designed to be stable and not adversely impact the hydrologic balance. Reconstructed channels <br /> at the Mine have not been designed with a lesser flow capacity than the unmodified stream <br /> channel immediately above and below the diversion (Rule 4.05.4(2)(b)). These channels are <br /> shown on Maps 41, 41A, and 4 1 B of the PAP. <br /> The Division has approved the use of riprap channel lining for reconstructed channels in the <br /> reclaimed area. Channel protection is warranted due to steep slopes and is necessary to provide <br /> long-term stability on the reclaimed area until vegetation is established. The riprap lining will <br /> provide stability in order to protect fills and property and to avoid danger to public health and <br /> safety (4.05.3(3)). Riprap used in Colowyo's channels to control erosion ensures channel <br /> stability and requires infrequent maintenance (Rules 4.05.4(2)(a) and (4.05.4(4)(b)). <br /> Minor realignments and changes in permanent stream channel profiles are permitted within <br /> reclaimed areas and excess spoil fill areas. Pre-mining and post-mining alignments are similar; <br /> however, profiles deviate more markedly (Maps 33, 33A, 33B and 33C of the PAP) for both <br /> smaller drainages and larger drainages. For larger drainages, the most significant example of <br /> altered profiles is Streeter Gulch. Pre-mining, Streeter Gulch was steep-sided with a 200-foot <br /> incised draw near the mouth of the gulch (PAP, Map 11). Initial box cut material for mining <br /> south of this gulch was placed near the mouth, first as an experimental practice and later <br /> recognized as excess spoil (overburden) fill. As a result, upstream topography was modified. <br /> The pre-mining profile ranged from 5 percent near the lower end and increasing to 12.5 percent <br /> for the upper 1,800 feet (measurements from Map 18 of the PAP). The post-mining profile is 30 <br /> percent for the first 1,000 feet up the face of the Streeter Spoil fill and approximately 4 percent <br /> Proposed Decision and Findings of Compliance January 5,2023 <br /> Permit Renewal No. 8 Page 136 <br />