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Creek, which in turn drains into Widefield Creek. Above t~e Wide- field Creek confluence with Fountain Creek, the drair.age area is approximately 15 square miles. The weste~n portion of El Paso County is in the Rampart Range of the Rocky Mountains, while the remainder is in a high plains region. Elevations r.ange from 14,110 feet to 5,150 feet at the sout~er~ county line. Physiographically, the study area east of Monument and Fountain Creeks is characterized by gently sloping plains: west of the creeks, by mountain ranges and basins. There are some horizontal sedimen- tary outc,ops in the Black Forest area which represent rock forma- tions from the Rocky ~IDuntain uplift some 60 million years ago. Ex?Osed sedimentary rocks along the edge of ~he mountai~ front are tilted. Above the sedimentary foothills the pre-Cambrian mountain core is largely of Pikes Peak granite. Soils of the regio~ exhibit characteristics that are directly related to their physiographic position. The highest of three physiographic positions. semiarid mountains and foothills, is comprised of rock outcrop and deep (greater than 40 inches to bedrock) to rr.oderately deep (20 to 40 inches to bedrock) soils formed by material derived from acid igneous rock or hard sedimentary rock. The lesser exten- sive soils formed through the erosion and weathering of acid igneous rock are 35 to 60 percent cobble with a loamy matrix, while more extensive soils formed with material derived from sedimentary rock generally are loamy with 0 to 25 percent gravel. The lowest of the physiog!:"aphic positions, semiarid to arid plains, has deep to shallow soils that form in eolian and alluvial deposits as well as material derived from clayey shales. Deep soils forming eolian and al:uvial deposits are well drained, sandy to clayey, and are usually lacki~g in rock (gravel or cobble) fragments, while shallow soils ~or~ed with ~aterials derived from shale are clayey, lacking :n signi~icant gravel, and are well drai~ed. T~e intermediate p~ysi09raphic position, semiarid foothills and plains, is dominated by soils derived fron hard sedi~entary rock, but also has a few soils forned i~ alluviam and fror.! interbedded sandstone and shale. Soils formec with material derived from hard sedime~tary roc~ are ~andy 0: loamy, well drained, and have less than 10 percent gravel (Reference 4). Generally, the nounta~~ and foothill areas have high coefficients of runo:f, steep stre2~ gradie~ts and narrow flood plains. Eigh plains areas ge~erally ~ave a lower coef:icient of r~noff, gradual elevatio~ changes, and relatively broad streambeds and =:ood ?~a~~s. Wi~hin ~~e region, preci?i~ation varies considerably because o~ elevatio;.s, major wind Currents, and :oca: geographic feat~res. Wi~t~r stor~s, typica:ly from the nort~west, tend to lose their h.0ist~~e on the western side of the Rocky Mountains. The ~ajor 8