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Show 144 PROBLEMS OP IMPERIAL VALLEY AJS1> GUNNISON EIVER. *!The Gunnison River which is the main tributary of the .Grand enters it from the south at the city of Grand Junction. It drains a roughly triangular area bounded on the east by the Continental Divide, which, also with the Uncompahgre Mountains, forms the southern boundary. On the north its boundary is the range between the main stem of the Grand and the Gunnison. Like other streams in the Colorado Basin the valley is comparatively open in the eastern part before leaving the slopes of the Continental Divide, but with distance to the west the soft sedimentary rocks of the great plateau region are reached and here the river has <jut deep canyons below the surrounding country which preclude irrigation diversion but which may give opportunity for high dams whereby hydropower can-be created. Irrigation development up to the present has been largely by indi-VKtuafeffort, but one large project of 100,000 acres, called the Uncompahgre, has been constructed by the Reclamation Service and furnished a water supply by diverting the waters of the main Gunnison through a 6-mile tunnel to the broad valley below the surrounding mesas which has been formed by the Uncompahgre River, one of the main tributaries of the Gunnison. Precipitation ranges from 8 inches at Delta, in the Uncompahgre Valley, which is in the western part, to about 18 inches in the eastern and higher parts, but most of the irrigable lands have precipitation running from 8 ,to 10 inches, of which practically 50 per cent occurs in the growing season. The average summer period between frosts ranges from 140 days at Delta to 65 days at Gunnison and is less at higher altitudes. Elevation of irrigable lands ranges from 5,000 at Delta to 7,700 at Gunnison, and of course irrigation in mountain valleys is found at much, higher altitudes. Mean annual temperatures lie between the extremes of 50° on the west at Delta to 37° at Gunnison and are lower with higher altitudes. The irrigation season <on the Uncompahgre project is from the middle of April until the middle of October, but decreases from that with increase in elevation to 60 or 90 days for wild hay lands in the higher altitudes. Agricultural products are those of diversified farming in the western part to wild hay, which is the main crop in the higher portions. Transportation is furnished by a standard gage branch of the Denver* oc Rio Grande, which extends from Grand Junction to Mont-rose and from Delta up the North Fork. A narrow gage branch of the Denver & Rio Grande extends from Montrose south to Ouray and beyond, and also from Montrose east to Salida, where it connects with tne standard gage. As a whole, the valley is exceptionally well provided with transportation as compared with most of the valleys of the Upper Colorado Basin. Not enough data are at hand to estimate diversion for new lands, but for the entire average and considering the aridity of the basin the consumptive use of water is estimated at 1.5 feet in depth in spite of the short growing season. Three small power plants on the tributaries, aggregating 3,000 orsepower, have been built to date. It is probable that other esirable sites exist on the tributaries, but no data concerning them re at hand. A possible site exists just below Montrose. |
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Original book: [State of Arizona, complainant v. State of California, Palo Verde Irrigation District, Coachella Valley County Water District, Metropolitan Water District of Southern California, City of Los Angeles, California, City of San Diego, California, and County of San Diego, California, defendants, United States of America, State of Nevada, State of New Mexico, State of Utah, interveners] : |