which the water will flow in the 13-mile newly driven Alva B. Adams tunnel through the Continental Divide, thence through five power plants eventually to be constructed. Carter Lake, Horsetooth, and other reservoirs will regulate the water for irrigation.

Gunnison River.-The Gunnison River and its tributaries, including North Fork and Uncompahgre River, irrigate 238,000 acres of fertile lands in west central Colorado. About 17,000 additional acres will be served when present enterprises are fully developed.

Upstream from Sapinero, 61,600 acres are irrigated along the upper Gunnison River, where lands are high, the growing season is short, water is abundant, and crop values per acre are low.

Fertile soils, good air drainage, careful husbandry, and extensive irrigation developments combine to make the lands along the North Fork River among the most productive in the basin. To irrigate adequately the 56,200 acres now under cultivation an annual diversion of from 3.5 to 5 acre-feet of water for each acre would be required. Only about half of the land now irrigated has a full water supply. Reservoirs and canals have been provided at relatively high cost. Some alterations in the present systems and exchanges of water rights together with new construction will be required for maximum use of the available water resources.

In the valley of the Uncompahgre River 70,400 acres are irrigated by the Uncompahgre project of the Bureau of Reclamation, and an estimated 17,000 acres more will be added when lands that have been drained in recent years are placed in production. A 6-mile tunnel carries water diverted from the Gunnison River west to project lands. The natural flow of the river, supplemented when necessary by storage releases from the upstream Taylor Park Reservoir, provides a full water supply.

Lesser tributaries of the Gunnison, including Cimarron Creek, Crystal Creek, Smith Fork, and Forked Tongue Creek irrigate substantial areas. These areas do not receive an adequate supply, particularly in the late-growing season. Water is pumped from the lower Gunnison to about 3,100 acres of land in Grand Valley, southeast of Grand Junction.

Three small ditches export water from the Gunnison River Basin across the Continental Divide to the Arkansas River and Rio Grande Basins.

Colorado River between Gunnison and Green Rivers.— Little land is irrigated directly from the Colorado River between the Gunnison and Green Rivers, but tributary streams serve about 45,600 acres. More than 80 percent

of these lands are within the Dolores River Basin and receive water from that stream and its tributaries. About 100,000 acre-feet of water also are diverted westward from the Dolores River to irrigate 30,000 acres of land in Montezuma Valley of the San Juan Basin, and 7,400

POTENTIAL DEVELOPMENT OF WATER Resources

Thirty-five potential projects for development of water resources in the Grand division are outlined. The irrigation of 224,000 acres of dry arable land and 160,220 acres of cultivated land lacking a full irrigation supply would be possible.

Nine hydroelectric power plants with an aggregate installed capacity of 288,000 kilowatts would be capable of producing nearly 1.6 billion kilowatt-hours of firm energy annually. Several other favorable power sites probably will be located when detailed surveys are made.

Some of the projects would provide municipal and industrial water supplies and recreational opportunities and in addition would benefit fish and wildlife.

Three additional projects would increase by 160,400 acre-feet present diversions to the San Juan area in the Colorado River Basin.

Possibilities exist for exporting annually an average of 1,492,000 acre-feet across the Continental Divide to the Rio Grande, South Platte, and Arkansas Rivers.

Potential projects are discussed under the three subdivisions of the Grand division.

Colorado River Basin above Gunnison River

Of the 14 projects which would expand irrigation by diversion from the Colorado River above Grand Junction, 3 are upstream from Glenwood Springs, 4 are in the Roar

ing Fork River area, and 7 divert from the main Colorado River or its tributaries between Glenwood Springs and the mouth of the Gunnison River. Two of these projects would increase power production. The water available for export from this subdivision would probably amount to 639,000 acre-feet.

Troublesome project. This project would serve lands located in Troublesome Creek Valley upstream from Glenwood Springs and northeast of Kremmling, Colorado. Two dams, one to impound 7,500 acre-feet of water at the Rabbit Ear site on Troublesome Creek and another to store 9,000 acre-feet on East Troublesome Creek, together with enlargement and extension of two service canals, would be required to provide water for irrigating 3,600 acres now inadequately supplied and 6,800 acres of new land. With the farm lands all above an elevation of 7,000 feet, a short growing season would limit crops to native grasses.

Muddy Creek project.-Muddy Creek flows south to join the Colorado River at Kremmling. Along its course are 2,520 acres of irrigated native grass land requiring supplemental water and 3,620 acres of irrigable land. A water supply could be provided by constructing a dam to store 7,000 acre-feet at the Barbers Basin site on Muddy Creek and a 17-mile canal to carry water from the reservoir to project lands.

Gore Canyon project.-Below Kremmling, Colo., the Colorado River flows through Gore Canyon where it falls 360 feet in 5 miles. This drop could be used to generate power by the construction of a low diversion dam at the head of the canyon and a tunnel to convey the water to a power plant at the lower end. Upstream regulation at the existing Green Mountain Reservoir on the Blue River and at other reservoirs that might be provided to furnish replacement water for transmountain diversions would help smooth out natural flows for greater firmpower production. With an.installed capacity of 30,000 kilowatts, the plant would generate 177 million kilowatthours of firm energy annually.

Fourmile project.-Located 8 miles southwest of Glenwood Springs, this project would irrigate 500 acres of new land and 1,400 acres in need of supplemental water. Existing ditches along Fourmile Creek, a tributary of Roaring Fork, could distribute the water, but a dam to store 2,000 acre-feet of water at Fourmile No. 4 reservoir site on Fourmile Creek would be required.

Cattle Creek project.-Only storage would need to be provided to irrigate 900 acres of new land and to furnish 5,500 acres with supplemental water. The lands are located along Cattle Creek, which flows westward to join Roaring Fork, 9 miles above Glenwood Springs. The offstream Missouri Heights Reservoir of 2,800 acre-feet capacity could be enlarged to a capacity of 9,000 acre-feet and filled by an enlargment of its 2-mile feeder canal from Cattle Creek.

Capitol Creek project.-A new service canal 10 miles long would be required to bring water from Snowmass Creek to 2,000 acres of grass lands now insufficiently irrigated from Capitol Creek. Both Snowmass and Capitol Creeks flow northeast and converge before joining Roaring Fork at Snowmass, 12 miles downstream from Aspen.

Woody Creek project.-Two thousand acres of irrigated land located near the junction of Woody Creek with Roaring Fork, 6 miles south of Aspen, could be furnished ample supplemental water by a new canal 13 miles long diverting from Roaring Fork at Aspen. Native grass is also the principal crop on these lands.

Silt project. First of five potential developments downstream from Glenwood Spring, the Silt project would require construction of a dam at the Rifle Gap site on Rifle Creek to provide storage for 10,000 acre-feet of water. Reservoir water would be released to present users from Rifle Creek and in exchange an equivalent amount from East Rifle Creek, a tributary, would be diverted southeastward through an improved Grass Valley Canal to supply 1,100 acres of new land and 5,200 acres now partially irrigated near Silt, Colorado.

West Divide project. This project, located south across the Colorado River from the Silt project, would supply water to 400 acres of new land and 7,700 acres now inadequately irrigated. A 7,000 acre-foot reservoir at the Haystack site on Middle Willow Creek would be provided but no new ditches would be required.

Hunter Mesa project.-On Hunter Mesa, located southwest of Rifle, Colo., and immediately west of lands of the West Divide project are 4,700 acres of dry land and 2,300 acres in need of supplemental water. An adequate water supply could be obtained from Buzzard Creek, a tributary of Plateau Creek, by means of a 10,000 acre-foot storage reservoir at the Owens Creek site on Buzzard Creek and a 27-mile canal to carry water to the lands.

Roan Creek project.-Along Roan Creek, which enters the Colorado River at Debeque, Colo., are 3,100 acres of irrigated land which could be furnished supplemental water by construction of a dam to impound 3,000 acrefeet of water at the Carr Creek site on Carr Creek, a tributary.

Collbran project.-In Plateau Valley in the vicinity of the towns of Collbran, Plateau City, and Mesa are 7,100 acres of new land and 18,900 acres irrigated with only a partial water supply. A 24,000 acre-foot reservoir at the Vega site on Plateau Creek, supplied by a 3-mile canal from Leon and Park Creeks, and two new distribution canals totaling 42 miles in length would provide water for these lands. An alternative plan would utilize part of the water for municipal purposes in the vicinity of Palisade, Grand Junction, and Fruita in Grand Valley.

Grand Valley project extension.-Five thousand acres of arable land above the highline canal of the Grand Valley project near Grand Junction could be supplied irriga

tion water by pumping from the canal with lifts ranging from 32 to 125 feet.

Cisco-Thompson project.-Scattered tracts of undeveloped arable land extend from Thompson, Utah, eastward across Grand County into Colorado. About 87,000 acres, of which all but 3,500 acres are in Utah, are situated below elevation 4,975 feet. Wedged between the Green and Colorado Rivers but high above both streams, these lands present a difficult problem to irrigation planers. From a reconnaissance investigation a gravity diversion from the Colorado River appears most practicable. The canal would head about three miles upstream from the town of Grand Valley, Colo., and continue on the south side of the river for 34 miles; thence crossing the river by siphon it would continue through a 13-mile tunnel and 140 miles of canal to the land, making its total length nearly 190 miles. High lands in Grand Valley could also be irrigated from this canal making unnecessary the pumping outlined in the Grand Valley project extension. Summer flow of the river would be insufficient to supply both this project and irrigation demands in Grand Valley. To make up deficiencies in Grand Valley, replacement storage could be provided at the Whitewater site 6 miles above the mouth of the Gunnison River, where, without detailed surveys, it is estimated that a dam 200 feet high would impound 12 million acre-feet. The upper 50 feet of storage would provide full stream regulation. With reservoir outlets 150 feet above the stream, a canal could run to the northeast, delivering water by gravity flow to the existing Grand Valley canal near Paliside, but a 45-foot pump lift would be required to serve the Highline canal. Water released through an outlet in the west abutment of the Whitewater Dam would irrigate 4,700 acres of land in the Redlands area south of Grand Junction. Power could be generated under a minimum head of 150 feet by release of surplus storage water from the reservoir. The power plant would have an installed capacity of 18,000 kilowatts and the annual output would amount to 100 million kilowatt-hours.

Colorado River-Yampa River diversion project.-By diverting surplus waters of the Colorado River at Kremmling, Colo., through a tunnel to the headwaters of the Yampa River, this project would substantially increase the power potentialities of the Yampa and Green Rivers (Green division) and reduce in a lesser amount the potential power output of the Colorado River in the Grand division. It presents an alternative possibility and merits further study.

Potential export diversions. Surplus water of the Colorado River above the entry of the Gunnison River could be exported eastward across the Continental Divide for use in the South Platte and Arkansas River Basins. With adequate diversion works and replacement storage reservoirs for supplying irrigation requirements in the Colorado River Basin, and either replacement water for power