1986-06-13_GENERAL DOCUMENTS - C1981018

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-5- • porosity. Recharge of thelbedrock aquifers occurs primarily at higher elevations north of the permit area through infiltration of precipitation in outcrop areas. Discharge is by small seeps along hill sides where aquifers are exposed by erosion along. the White River, and to a very minor extent, by pumping of wells in the past. The discharge of the ground water in the Iles Formation has not been identified. The alluvial aquifer along the White River contains gravel , sand, silt and clay sized material which causes the alluvium to be much less permeable than would normally be expected. The White River alluvium near the permit area has a maximum depth of 37 feet. Ground water in the alluvium occurs in an unconfined condition. Within the alluvial aquifers, recharge'-is from precipitation, bedrock aquifer discharge, and directly from the river. Discharge from the alluvial aquifer occurs through discharge to the river, from transpiration by riparian vegetation and by the pumping of wells in the past. Western Fuels has developed an alluvial well field near the confluence of Scullion Gulch and the White River. This alluvial water is used for mine operations. In 1984, Kenney Reservoir, above Rangely, Colorado was completed. This reservoir impounds the White River through the southern portion of the permit area, innundating the alluvial well field. As the alluvial surface is almost • completely submerged by the Reservoir, recharge to the well field is now instantaneous. The movement of Mesaverde ground water is controlled by the Red Wash Syncline and major fracture zones located along Red Wash, Scullion Gulch, and the White River. Ground water in the northwest part of the mine plan area moves down dip and then normal to the'i' Red Wash Syncline. Within the central and southern portion of the mine plan area, the ground water moves in a more southerly direction toward the White River, in response to the permeable fracture zones. Drainage patterns are incised and dendritic, with Scullion Gulch draining 11 .8 square miles and Red Wash draining 122.5 square miles. Runoff events in both these streams are primarily in response to snowmelt and rainfall . Red Wash also receives flow from springs located at higher elevations approximately six miles north of the permit area. There are no springs in the permit area itself, although seeps exist at various sites along the Red Wash channel . The White River, which will receive discharge from the permit and adjacent area is a perennial stream. Water quantity in the White River exhibits seasonal variations typical of snowmelt rivers in the semi-arid regions of the intermountain west. The majority of flow in the White River occurs between May and July in response to snowmelt. Flows begin to decrease in July, increase slightly in October, in response to thunderstorm activity, and decline steadily until precipitation increases again in March. Surface water quality in the White River is characterized as a calcium-sulfate type. The soils hove developed in residuum from interbedded sandstone and shale or locally derived alluvium. There are also small areas of aeolian deposits on the lee sides of ridges.