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>4! ..... - ~. C HAFTER I GENERAL DESCRIPI'ION project to the storage project and over-all basin development is given in the Bureau of Reclamation report of December 1950, entitled Colorado Eiver Stora..e~ Project ~ Participating Projects. Physical Geography Location Potential project lands are from 5,450 to 7,200 feet above sea level. They are located in the southwest corner of Delta County, separated from the rest of the county by the Gunnison River on the west and the North Fork River on the north. The lands are bordered on the south by the Delta-~10ntro3e County line and on the east by the West Elk J.fountains, a spur of the main Elk Mountains, The project area is about 60 miles west of the Continental Divide and 20 miles south of Grand Mesa. Grand Mesa, a high mountain plateau; is one of the most prominent landmarks of the region and, with the Elk Mountains, forms the drainage divide between the Colorado and Gunnison Rivers. The town of Crawford is located near the center of the project area. It is 32 miles southeast of the city of Delta and 73 miles southeast of Grand Junction. Physical Feature~ Smith Fork heads in the high peaks of the West Elk Mountains and flows westward in a deep valley it has cut in the mountains through igneous and sedimentary formations. From the mountains, which termi" nate abruptly at the eastern edge of the project. area, Smith Fork con- tinues westward through foothill and mesa areas to its junction with the Gunnison River. The Gunnison River then continues to its junction with the Colorado River. Iron Creek joins Smith Fork a half mile west of Crawford in a narrow canyon. Cottonwood Creek, a small tributary of the North Fork River, flows through the project area. Its run-off, however, consists mostly of spring flow and would not be utilized as a part of the project water supply. The region in which the project area is located dips gently to the northeast. The continuity is broken by an anticlinal fold about 25 miles long and 15 miles wide. Carved in the crest of the fold is the Black Canyon of the Glli~son, a spectacular, vertical-walled gorge which ranges to more than one-half mile in depth. Old pre-Cambrian granites and schists which are unconformably overlain by the Morrison formation are exposed in the canyon. The Morrison formation and ather sedimentary formations of the Jurassic, Cretaceous, and Tertiary periods are found in the project area and are the parent materials of project soils. The West Elk Mountains are of volcanic origin and were formed during the Tertiary period. ~ 2