2013-10-02_PERMIT FILE - C1981019A (2)

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RULE 2 PERMITS Flood Irrigation The irrigated land and topography of those areas that are currently or were historically flood irrigated are shown on the Regional Hydrology Map (Map 10). Subirrigation The channel fill of the floodplains in the canyon areas should be expected to be comprised of unconsolidated deposits in conjunction with tight, sticky clay material. Impermeable clay surrounding unconsolidated deposits generally effectively prevents the transmission of water to or from the overlying stream and root zone. Due to the narrow area in the floodplains, the overall slope of the drainage and expected clay deposits, the likelihood of a developed subirrigation in these areas is questionable. Water Duality and Muantity Since 1974, Colowyo and other private and governmental groups (VTN, BLM, USGS) have collected samples of water flows and water quality. The results of all this work is summarized in section 2.04.7. Aerial Photograph Analysis Aerial photographic coverage of the permit area and adjacent area has been complied by the OSM in Denver, Colorado. The photographs are infrared and show the late summer and fall season differences in vegetative growth between upland and valley floor areas. Goodspring Creek shows some evidence of being an alluvial valley floor. Effects on Essential Hydrologic Functions Based on information accumulated, the effects of mining on any alluvial valley floor which exist in the general area would be minimal. Because of the undefined perched existences and limited amounts of groundwater in the area to be mined, the planned mining will not directly impact any alluvial valley floor. Any water recharge of the nearby drainages and unconsolidated material from the mine would be negligible in comparison with the overall natural flows of the streams recharged in areas above the operation. The flood plains of Goodspring Creek, Wilson Creek and lower Taylor Creek may meet the geomorphic criteria and flood irrigation requirements of an alluvial valley floor. Runoff from the mining operations drains into these floodplains. Therefore, Colowyo was taken appropriate measures to protect the essential hydrologic functions by designating stream buffer zones and by installing sedimentation ponds on the drainages from disturbed areas feeding into Goodspring Creek, Wilson Creek, and Taylor Creek (see Hydrology - North Map (Map 11) and Hydrology - South Map (Map 12)). The overall role of the floodplains in collecting, storing, regulating and yielding water for agricultural activities has been unchanged and should continue to be unaffected by the mining operations. The- possible alluvial valley floors in the vicinity of the mine will incur no adverse impact due to mining by Colowyo. Surface water pollution will be prevented by sedimentation ponds, sediment control measures, proper mining and reclamation techniques, and frequent monitoring of discharge water quantity and quality. The hydrologic consequences of mining will not result in disruption of the essential hydrologic functions due to the beneficial effects of water treatment and flood control provided by the sedimentation ponds and natural dilution of potential mine discharge to the existing streams. Rule 2 Permits 2.06-7 Revision Date: 6/23/08 Revision No.: MR-91