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headwaters to its confluence with Gunnison River at Delta, Colorado, located approximately 12 miles downstream of the town. Elevation differences in the drainage basin range from 13,000 feet in the headwater areas to approximately 4,900 feet at the mouth. The average elevation of Olathe is approximately 5350 feet. The total watershed area drained at Olathe is approximately 760 square miles, The widely varied topography of the region (mountain ranges, high plateaus and mesas, and the comparatively high Uncompahgre River valley) creates distinct and varied climatic conditions. Low humidity and mild year-round climatic conditions generally prevail due to the protection afforded by surrounding high mountain peaks, which tend to attract moisture from passing storms, but also protect the valley from high-velocity winds. However, temperature often drops below freezing in winter and rises to over gOOF in summer. Average monthly mean temperature records at Olathe are unavailable, but temperatures range from 26,40F to 74.loF at nearby Delta, Colorado. Normal annual precipitation averages approximately 8 inches (Reference 3). Rain Occurs throughout the year, with the smallest amount in June and the largest amount in August. Average annual snowfall is nearly 30 inches. In the high headwater regions, normal annual precipitation averages nearly 45 inches occurring mostly as snow that usually accumulates into a deep snowpack. Four general soil association6 predominate in the Uncompahgre River watershed. In the lower basin, including the site of the Town of Olathe, the Billings-Christianburg Association is made up of deep, nearly level and gently sloping, fine-textured to moderately fine-textured soils on alluvial fans, flood plains, and terraces. The Chipeta persayo Association, also located in the lower basin, consists of shallow, nearly level to hilly, fine- textured to moderately fine-textured soils derived from shale or mudstone. The Bostwick-Cerro Association is found in the upper basin areas. It is composed of deep, gently sloping, moderately fine-textured soils on alluvial fans and valley side slopes. The Rock Outcrop- Travessilla Association is composed of bare rock outcrop and shallow, rolling to steep, moderately coarse-textured soils found on hills, ridges, and sides of mesas. Vegetation in the valley, where still undisturbed by agriculture, and on the lower mountain slopes consists of narrowleaf cottonwood and Russian oliver shrubs and brushes such as will~l, wildroser and buffaloberry: and native grasses. In the higher mountainous areas, vegetation includes an understory of native grassesj willow and a variety of berry shrubs; and stands of quaking aspen, dwarf juniper, Engelmann's spruce, and subalpine fir. Much of the area above timberline is barren and rocky. 4