Watershed Work Plan for Watershed Protection and Flood Prevention West Cherry Creek Watershed

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3- DESCRIPTION OF ME WATERSHED Physical Data Location.- The West Cherry Creek Watershed is located in east - central Colorado and includes parts of E1 Paso and Douglas Counties. The watershed is 15 miles in length and averages 3.2 miles in width. The total area is 31,360 acres (49.0 square miles), of which 12,160 acres is in E1 Paso County and 19,200 acres is in Douglas County. West Cherry Creek rises in the Black Forest on the north slope of the Arkansas -South Platte Divide, and flows north about 15 miles where it joins East Cherry Creek to form Cherry Creek proper. Cherry Creek is a tributary of the South Platte River. Topography West Cherry Creek lies in the Great Plains physiographic province. The drainage parallels the eastern Front Range of the Rocky Mountains. Elevations range from 7,700 feet above sea level at the head of the drainage to 6,700 feet at the lower end where East and West Cherry join to form Cherry Creek. The topography of the watershed is very rolling with ponderosa pine growing along the higher ridges. The channel gradient is between 40 and 60 feet per mile. The tributary streams are short with steep gradients and average about three miles in length. Geology.- The principal outcropping bedrock formation is the Dawson arkose of Late Paleocene geologic age. This formation consists mainly of light colored, loosely cemented arkosic sandstone. Unconsolidated sand and gravel deposits of Pleistocene age occur in terraces along the main stream valley. " Alluvial deposits of Recent age cover the valley bottoms and lower slopes. Soil and Cover - The soils are practically all formed from the Dawson formation. A small amount of silty loess is also present. The soils derived from the Dawson formation are characterized by high plasticity and low infiltration rates. The soils may be divided into five main groups: sandy soils, moderately sandy and moderately heavy soils, sandy and gravely forest soils, alluvial soils, and rough broken lands. The sandy soils make up about 25 per cent of the total. These soils have loamy sands or light sandy loam surface with a sandy loam subsoil and vary- ing quantities of gravel scattered throughout. They are generally over five feet in depth. The moderately sandy soils and the moderately heavy soils make up about 43 per cent of the total. Surface soils range from sandy loam to loams with subsoils of sandy clay loams to clays. Structure is good and depth is usually over five feet. The same type of vegetation is found on both soils with highest production occurring on the sandier surface soils. Sandy and gravely forest soils make up about 17 per cent of the total area. These soils are quite shallow, less than two feet deep. The underlying material is fractured and often unconsolidated. Pine trees are the dominant vegetation on this soil. Alluvial lands make up about six per cent of the area and are generally sandy on the surface. They are deep and usually support wet meadow vegetation.