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• -6 • Within the vicinity of the Trapper Mine. ground water exists i'n both bedrock and alluvial aquifers. Major bedrock aquifers in the area are the Trout. Creek, Middle, Twentymile, and White sandstones; The major alluvial aquifers in the area are those associated with the Yampa and Williams Fork Rivers. Many of the coals, discontinuous sandstones and siltstones, and some of the smaller alluvial formations are also water-bearing. However, they contain insufficient quantities of water to be considered major aquifers. The climate of the region is classified as highland continental, and is char- acterized by Iow precipitation, large fluctuations in diurnal temperatures, low humidity, moderate wind, and high levels of insolation. The local climate of the Craig, Colorado area is characteristic of the semi-arid steppe regions. Due to massifs to the west and east of the Craig area and the corresponding orographic effects, this locale experiences a high number of dry, clear days., The average annual precipitation for the area is 13.5 inches, of which over one-third is snowfall (averaging 66.5 inches/year).. The mean annual tem- perature is 43°F, with recorded extremes of -45°F and +700°F. Winds are predominantly from the west, but are locally nndified by geomorphic features. The growing season for the area around Craig averages 77 days. The permit area is occupied by three soil orders; Aridisols, Entisols, and Mollisols. These soil orders are characteristic of fairly steep, semi-arid regions of Northwestern Colorado. They represent soils that grade from recently developed soil bodies with minimum horizon development (Entisols) to older soils with well-defined diagnostic horizons (Mollisols). Overall, the soils found in the proposed permit area are relatively deep and fairly well-drained. Effective rooting depth varies from 20-60 inches within the area. The deepest soils yielding the greatest rooting depths occur within valleys and on the leeward side of ridges. Soil reaction is slightly acid to moderately alkaline over the permit area with the exception of inclusions of small scattered areas with saline substrata. These small areas have probably formed in place from weathered sodic shales. Vegetation in the area grows largely in response to macro climatic influences of the region. The north-facing slopes, having moderate to deep soils, a relatively mesic moisture regime, and favorable levels of insolation through- out the year are characterized by well-developed mountain shrub communities. On the colluvial toe-slopes, communities dominated by sagebrush and some grasses occur. On the south-facing slopes behind the ridgeline of the Williams Fork mountains, vegetative commmunities are not as well-developed in terms of cover, density and production due to the less favorable soils, moisture regime, and increased solar insolation. The trend in these areas is toward communities dominated by juniper, pinyon, mountain mahogany, and xerophytes. Within the permit area, natural vegetative communities have been modified to varying degrees by man and domestic animals. Much of the Land along toe- sZopes and valley bottoms has been cleared of native vegetation and is currently utilized for dryland agriculture. Most of the north-facing slopes in the area have been historically used for the grazing of sheep and/or cattle. Due to the above, the permit area is characterized by a mosaic distribution of communities.