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<br />EXHIBIT D-3 <br />Page 7 <br />The landscape is gently sloping to steep lower mountain slopes with <br />intervening canyons, mesas, and outwash fans. Vegetative cover includes <br />grass, ponderosa pine, serviceberry, oakbrush, aspen, and sagebrush. <br />About 60 percent of this unit has dark-colored surface layers to a depth <br />of 8 to 24 inches. Organic matter content is high. Surface layers and <br />subsoils are usually medium to fine textured. Depth to underlying parent <br />material, mainly shale and sandstone, is 20 to 60 inches. The soils are <br />noncalcareous to depths of 10 to 30 inches. About 20 percent of the unit <br />is less than 20 inches deep over shale and sandsone. Surface layer <br />thickness ranges from 4 to 10 inches. Textures vary according to parent <br />material. Another 15 percent has dark-colored surface layers with a gray <br />subsurface layer ranging from 2 to 12 inches in thickness. Depth to <br />underlying material is 20 to 60 inches. These soils are neutral to <br />slightly acid. Ponderosa pine or oakbrush are usually dominant to these <br />soils. The remaining 5 percent of the unit consists of mixed alluvial <br />soils, some of which are poorly drained. <br />Soil Mapping Unit 6: Light-colored soils of the cold mountain sloQee <br />There are several small delineations of this unit whicfi is mostly within <br />national forests. They are in the southeast part of the basin except for <br />one that follows the divide from near Spruce Mountain to the upper reaches <br />of Horsefly Creek. This unit comprises only about 4.5 percent of the <br />basin but has a high water yield. <br />The landscape is a strongly sloping to steep mountainous terrain <br />dissected by numerous perennial mountain streams. A dense cover of <br />spruce-fir (conifer), mainly Engelmann spruce, is dominant. <br />Most of this unit has acid forest soils with a surface litter of needles <br />and twigs. About 58 percent of the soils have a dark-colored surface <br />layer less than 4 inches thick. Below this is a light-colored, gray, <br />subsurface layer ranging from 6 to 30 inches thick that is moderately <br />coarse to coarse textured. The underlying subsoil has blocky structure. <br />Textures range from moderately fine to coarse. Some are gravelly or <br />stony. Depth to underlying parent material is usually more than 30 <br />inches. Another 20 percent of the unit is similar to the previous <br />description except that the surface layers are dark-colored to depths of <br />8 to 20 inches. The gray subsurface layer is 4 to 20 inches thick. <br />About 20 percent of the unit has soils with bedrock at depths of 20 <br />inches or less. The surface layer is dark-colored and about 7 inches <br />thick. The gray subsurface layer is usually absent. The remaining 2 per- <br />cent is composed of poorly drained alluvial soils along the drainageways. <br />'~. <br />'~ <br />