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<br />-5- <br />Rule 2.U 5.3(4) - Ponds, Impoundments and Diversions <br />1. *Designs for the diversion and collection ditches need to be submitted <br />that show they can handle the lU year, 24 hour storm event with 0.3 <br />feet of freeboard. The designs should detail peak flow calculations, <br />ditch dimension, channel lining characteristics, and acceptable flow <br />velocities. <br />The specific ditches requiring designs are: <br />a. The roadside ditch from the North Spoil area. <br />b. Collection ditches used on the portal bench. <br />c. The roadside ditch leading from the upper bench. <br />y <br />d. The entrance road ditch from the county road to the office. <br />e. Upland diversion aitches. <br />f. The contour ditch that diverts water away from the Lewis Gulch <br />fill. <br />2. Water that flows down the road from the upper bench area crosses the <br />area 100 feet south of the office area. It would be good practice to <br />y route this water throuyh the area with a yraded low spot, a culvert, <br />or across drain. This will prevent muddy conditions and prevent the <br />road drainage from entering the leach field. Please indicate your <br />preferred method of handling this water. <br />3. Since the upper bench only contains a water tank and is less than one <br />acre in size, it qualifies as an exemption for sediment ponds. The <br />proposed pond for this bench can be approved as a check dam and <br />requires no change in design or operation. <br />4. The operator has provided adequate sediment storage in the sediment <br />ponds and should agree to clean the ponds when the sediment reaches <br />60'~ of sediment storage capacity. Would the operator agree to <br />installing a marker that clearly indicates the 60% sediment levell <br />The marker could be a wood stake, rod or post with a florescent paint <br />sprayed at the 6 ~~ level. The marker would yreatly aid the operator <br />in properly maintaining the pond. <br />5. The operator is reminded that upon completion, the sediment ponds <br />will need to be surveyed and certified by a qualified registered <br />professional engineer. The certification shall be forwarded to the <br />Division, and state that the ponds were constructed according to the <br />approved designs contained in the application (Rule 4.U 5.6(1}}. <br />