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in the region tend to be inversely related to elevation (U.S. Bureau of Land Management, 1978), mean <br />monthly temperatures are probably somewhat lower in the lease area than in Rangely. Precipitation in <br />Rangely averaged 9.50 inches annually between 1950 and 1995 (National Weather Service). <br />Approximately 45 percent of this precipitation occurs during the months of November through April, <br />primarily in the form of snow. This relatively low average annual precipitation, being less than the expected <br />evapotranspiration demand, indicates that the area contributes only a small amount of water to the surface <br />or subsurtace hydrologic system. <br />II.C.1.d Vegetation (See also Section II.F) The lease area is covered primarily by three vegetative types <br />(gently et. al., 1978). Greasewood communities occur along stream channels, occupying much of the <br />alluvial fill adjacent to the White River, Red Wash, Scullion Gulch, and their tributaries. Pinyon-juniper <br />woodland communities are located along the ridges and plateaus at the higher elevations of the lease area. <br />Between these two communities is a sagebrush vegetative type. <br />Each of these communities is typical of areas where evapotranspiration exceeds precipitation, indicating <br />that the area does not contribute significantly to groundwater recharge. Because of the general sparsity of <br />vegetation and the presence of erodable soils, the area has the potential of yielding a large amount of <br />sediment. <br />II.C.2 Surface Water HYdrologv <br />• II,C.2.a Regional Surface Hydrologic System The lease area is situated in the lower White River Basin <br />(see Figure II.C-3). 5nowmelt is the primary source of surface water, originating mainly on the north slopes <br />of the White River Plateau (lours et al., 1965b). The U.S. Department of Agriculture (1966) reports that <br />approximately 94 percent of the annual stream flow of the White River comes from the upper 27 percent of <br />the basin. Thus, much of the basin, including that occupied by the lease area, is drained by ephemeral and <br />intermittent streams which flow only during a relatively short time of the year, if at all. <br />Streamflow variations of the White River are typical of snowmelt rivers in the semiarid regions of the <br />intermountain west. Peak flows generally occur during the month of June with the months of May through <br />July normally accounting for most of the annual stream flow. The flow of the White River, however, is <br />somewhat peculiar because it has a fairly high sustained base flow, probably the result of groundwater <br />storage in the formations underlying the White River Plateau (lours et al., 1965b). <br />. Permit Renewal #3 (Rev. 8/99) I I . C-6 <br />