AZ vs. CA:24 California Exhibits, Vol. XXIV; Miscellaneous

page 146

146 PROBLEMS OF IMPERIAL VALLEY AXD VICIXITY. Existing power plants, Gunnison River-Grand River Basin. [E. C. La Rue, W. S. 395, p. 174.] Name. Location. Operating head. Installed capacity. Stream. County. State. Kilowatts.1 Horsepower.2 Ames.......... /Howards Fork......... \Lake Fork............. San Miguel__ Colorado...... Feet. 580 835 490 }¦ 3,600 1,200 6,200 Ilium.......... South Fork............ .....do........ ...do........ 1,600 1 Figures represent rated capacity of generators. * Figures represent rated capacity of water wheels. POWER SITES. Only one is known, which is at Montrose. No data available. DOLORES RIVER DRAINAGE. The Dolores River, together with its principal tributary, the Sari Miguel, drains a roughly rectangular area 60 miles wide and 100 miles.long between the Gunnison and San Juan watersheds, with its principal axis in a southeast-northwest direction. The area is in general a high plateau warped and eroded to a high degree. The Uncompahgre plateau, in reality a broad topped mountain range of 8,000 to 9,000 foot elevation, borders the northern side. The western tip of the San Juan Range forms the eastern tip of the area and the La Plata Range forms the southeastern boundary. The southerly boundary is a low divide on the eastern end, succeeded in the southwest corner by the La Sal mountains which cover much of the western corner of the area and reach altitudes exceeding 12,000 feet. The easterly end of the entire drainage area is roughly bisected by the low San Miguel range. With the exception of the higher mountains the entire area is composed of relatively soft sedimentary rocks through which all living streams have readily cut canyons whose depths rapidly increase as the headwaters are left and then decrease as the central position of the main valley is approached. The Dolores River drains the southern slope of the San Miguel range and part of the La Plata mountains along the southeastern border of the area, and after skirting the southwestern edge of the plateau for 50 miles, turns abruptly north, breaking through numerous ridges, joins the San Miguel River and resumes its northwesterly route to the Grand River. The San Miguel River drains the northern slopes of the San Miguel range, the western tip of the San Juan Range, and a part of the Uncompahgre plateau. Irrigation development is largely confined to the central region bounded by the Dolores River on the south and west, the San Miguel range on the east, and the San Miguel River on the north. This region is a secondary plateau sloping steeply to the west and consisting of parallel ridges and valleys running northwest-southeast. \^ater can be supplied to this region from creeks heading .in the San Miguel range or from San Miguel River but not from the Dolores River owing to the depth of its canyon. Outside this area either the