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Two alluvial valley floors are formed in synclines within the permit and adjacent area. These are the alluvium associated with the Williams Fork and Yampa Rivers. The Williams Fork alluvium averages 800 to 1,000 feet wide within the permit area, and the Yampa River alluvium is up to 9,000 feet wide and averages 5,000 feet in the permit area. Ground Water Hydrology There are five bedrock aquifers within the permit and adjacent areas of Eagle Mines. These aquifers are the Tow Creek and Trout Creek sandstones of the - Iles Formation, the Middle sandstone, the Twentymile sandstone and the White sandstone of the Williams Fork Formation, The alluvium of the Williams Fork and Yampa Rivers contain ground water. The alluvia are generally recharged laterally by adjacent rock aquifers, by direct infiltration of precipitation, by irrigation waters, or by surface water flow. The alluvial ground waters discharge into the rivers, producing baseflows, Climate The climate of the region is classified as highland continental. It is characterized by low precipitation, large fluctuations in diurnal temperatures, low humidity, moderate wind, and high levels of insulation. The local climate of the Craig, Colorado area is characteristic of the semi-arid steppe regions. The average annual precipitation for the area is 14.0 inches, of which over-one-third is snowfall (averaging 66.5 inches/year). The mean annual temperature is 43oF, with recorded extremes of -45oF and 100oF. Winds are predominantly from the west, but are locally modified by topographic features. The growing season for the area around Craig averages 77 days. Soils Three soil orders are found within the proposed permit area; Aridisols, Mollisols and Entisols. Topographic features have played a significant role in the development of these soil bodies. Generally speaking, the Aridisols and thinner Mollisols are found in the fairly steep areas on the eastern portion of the proposed permit area and the thicker Mollisols and Entisols along the bottom areas of the Williams Fork drainage. However, overall the soils encountered are relatively deep (except for outcrop areas) and fairly well-drained. Effective rooting depth varies from 20-60 inches, with the most productive soils found in the bottomland areas. Soil reaction is neutral to slightly saline, with the exception of small scattered saline or sodic substrata. These small isolated areas probably formed in place from weathered sodic shales. The permit area has had a history of surface and underground mining which resulted in several areas of disturbance prior to the enactment of current reclamation caws. In these areas, which include the Ho. 5 and 5A portal areas, portions of the coal processing waste pile area, the crusher site and the old shop and temporary office, no topsoil was salvaged or stockpiled. Since the enactment of the Colorado Mined Lartd Reclamation Act of 1976, topsoil has been salvaged and stockpiled from the disturbed areas. -9-