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<br /> SURFACE WATER <br />C <br />~ ~ Water Control Plan <br />.I <br />a <br />~ <br />~ ~ <br />~\ <br />~`v,k The applicant has proposed a system of diversion ditches, <br /> impoundments, and sedimentation ponds to control runoff. As <br /> shown in Figure 2, most of these structures are satisfactorily <br />•~~ <br />~' <br />located to ensure that no runoff from disturbed areas enters <br /> North Fork of Bolton Draw. The one exception is runoff from the <br /> <br />~~~ ~ area of Phase IX. Water control should be provided to route <br />~ ~~ le into the area which drains <br />drs~i-na~e_ from the propd Stock`i <br /> - <br /> to Pond 4. Therefore, the following stipulation is. proposed. <br />The applicant must review the proposed surface water <br />control plan and add additional ditches to control <br />runoff from Phase IX as necessary. This information <br />must be submitted before mining can begin in this <br />area. <br />Ponds and Impoundments <br />,~ <br />Four sedimentation ponds and one temporary impoundment are <br />~ ~ proposed. Of these, all but Pond 4 provide adequate storage for <br />~ ~ the 10 year, 24 hour event. Pond 4 is underdesigned because <br />~- ~- <br />,,~ yroundwater seepage (1,300 gpd maximum) was not included. In <br />o ~ order to rectify this deficiency, the following stipulation <br />~ should be implemented. <br />y <br />Pond 4 must be redesigned to provide sufficient <br />~ storage for sediment, the 10 year, 24 hour event, and <br />~ groundwater seepage as referenced in the calculations <br />` - in Appendix Q of the permit application. <br />~ 3 <br />No primary outlet is provided for the temporary impound- <br />ment.. The emergency spillway is correctly sized for the 25 year <br />' event, as is ditch E, but since the runoff from this 211 acres is <br />_72_ <br />