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• indicated acceptable water quality levels for pH, total suspended solids, total dissolved solids, setteable solids, oil and grease, and total iron (copies of these reports are on file at the mine site and the CDMG offices). Therefore, it is expected that this impoundment will continue to adequate water quality for the posCmining land use and not result in any diminution of water quality for downstream users. The ratio of watershed area (in acres) to impoundment permanent pool volume (in acre-feet) is approximately 49.5:1. A 60:1 ratio is generally recommended by the Soil Conservation Service for northwest Colorado (Figure 10, SCS Agricultural handbook number 590). Although the actual ratio is slightly less than that recommended, the ratio of watershed to impoundment should be adequate and suitable for the intended purpose. This impoundment will not result in diminution of quality or quantity of water uses downstream since the impoundment is currently at its permanent pool elevation. Even if the water level in the impoundment needs to be pumped down sometime in the future to facilitate maintenance, there should be very little lag time associated with the water level in the impoundment reaching the permanent pool elevation. This permanent impoundment will have a positive effect on down stream users in that peak flood flows will be retarded and • released downst ream at a slow and steady rate. The impoundment has adequate and safe acc ess for the proposed water users (livestock and wildlife). The Soil Conservation Service generally recommends that a seven foot minimum depth of water be maintained in ponds in most subhumid areas (Figure 11, SCS Agricultural Handbook #590). Consequently when sediment control is no longer needed, the mine will ensure that the permanent impoundment has at least seven feet of depth. Technical Revision 32 4.6R-4 September 5, 1995