The Colorado River Storage Proiect and participating proiects Artist's conception of Glen Canyon Dom UNITED STATES DEPARTMENT OF THE INTERIOR Bureau of Reclamation, W. A. Dexheimer, Commissioner FOREWORD The Colorado River storage project was author­ drains a part of N" cw ;,.Icxico and Arizona through ized by the Congress in legislation which was the San Juan River. signed into law by President Eisenhower on The area contains a scarcely tapped potential of April 11, 1956. agricultural, industrial, and recreational assets. It This law (P. L. 485, 84th Cong.) provides for the contains tremendous quantities of uranium, coal, development of the water resources of the Upper and other minerals. Realization of the potential in Colorado River Basin, an area which has been economic growth and contribution to the national described as the "last water-hole" of the vYest. welfare is dependent on ma:s.imum utilization of The Upper Colorado River Basin, covering parts limited water supplies. The Colorado River stor­ of Utah, Wyoming, Colorado, New Mexico, and Arizona, is an area of approximately 110,000 square age project is planned to conserve the very limited miles between the high crests of the Rocky Moun­ precipitation which falls principally in the form of tains in Colorado and Wyoming, and the Wasatch snow in the high mountains and utilize it for ;,.fountain spur in Utah. The southern portion municipal, industl'ial and agricultural growth. 385481- 56 HISTORY The need for the Colorado River storage project In prolonged dry periods there is not enough was envisioned by the Colorado River Compact of water to permit the Upper Basin to consume its 1922. In dividing Colorado River water between allotment under the 1922 compact and at the the pper and Lower Colorado River Basins, the same time make the required deliveries to the compact permits the Upper Basin to consume 7}~ Lower Basin. In wetter periods, however, flows million acre-feet of water each year. However, arc more than sufficient for these purposes. this allocation is contingent upon the Upper Large storage reservoirs thus are needed to be Basin delivering to the Lower Basin not less than filled when flows arc high and to provide addi­ 75 million acre-feet of water in any period of 10 tional water when needed for compact fulfillment. consecutive years and to deliver additional water Favorable opportunities for such reservoirs are for use in ::\1exico under certain circumstances. provided by the deep canyons of the Colorado The dividing point between the two basins is at River and its principal tributaries in the Upper Lee Ferry near the northern border of Arizona. Basin. Water allocated to the Upper Basin was further A plan for the Colorado River storage project, apportioned to the individual States of Arizona, including a series of dams and reservoirs to provide Colorado, ew Mexico, Utah, and Wyoming by storage capacity in combination with power devel­ the Upper Colorado River Basin Compact of 1948. opments and other services, was presented in a This compact also created the Upper Colorado Bureau of Reclamation report in 1950, which was River Commission, consisting of representatives subsequently printed as H. Doc. No. 364, 83d of the Federal Government and each compacting Congress, 2d session. The plan had been formu­ State except .Arizona. lated in cooperation with other Federal agencie The flow of the Colorado River is extremely and with the pper Colorado River Commission. erratic, varying from 4 million to 22 million acre­ An initial group of "participating projects" feet annually al Lee Ferry. There is a tendenc:v that would develop water for irrigation and other for the high years and the lo"- years to be grouped, purposes in the Upper Basin and that would be thus accentuating problems of river regulation and linked financially with the storage project was use. also presented in the 1950 report. PROJECT AUTHORIZATION Construction of four storage units of the Colo­ N"avajo Unit on the San Juan River in X ew MeA.'ico rado River storage project and 11 participating and Colorado (dam and reservoir only). projects was authorized by the act of April 11, Curecanti nit 0 1.1 the Gunnison River in Colorado 1956 (P. L. 485, 84th Cong.). Authorized devel­ (subject to further engineering and economic opments are listed belo\\-. investigations and to a limitation on the height of the principal dam of the unit). TORAGE PROJEC'r UXITS Glen Canyon Unit on the Colorado River i'.1 PARTICIPATING PROJECTS Arizona and Utah. Central Utah (initial phase), tah. Flaming Gorge Unit on the Green River in Utah Emery County, Utah. and Wyoming. Florida, Colorado. 2 Hammond, Kew ~Iexico however, lo interfere with or preclude considera­ La Barge, Wyoming. tion and authorization of other additional projects Lyman, Wyoming. in the comprehensive plan of development. Paonia, Colorado (works additional to existing X one of the authorized dams or reservoirs will project). be constructed within any national park or monu­ Pinc River Extension, Colorado and X ew 1Iexico. ment. Appropriations, not lo exceed "760,000,000, Seedskadee, Wyoming. were authorized lo carry out the purposes of the Silt, Colorado. act. This is the largest expenditure ever author­ Smith Fork, Colorado. ized for a Reclamation development at one lime. In the investigations of additional develop­ The Eden project in Wyoming, which is n°'" ments in the Upper Basin, twenty-five additional largely constructed, would, by terms of its author­ potential participating projects are to receive izing act of June 28, 1949, become financially priority consideration in tne completion of plan­ related to the Colorado River storage project ning reports. It is not the intent of Congre s, as a participating project. CONSTRUCTION FEATURES Storage project un its During construction, the river will be dive1'Led through two concrete tunnels, each of which will The four authorized storage units will provide be about 45 feet in diameter. One will be localed about 32,000,000 acre-feet of reservoir capacity and on each side of the canyon. The lower portion about 1,100,000 kilowatt of installed generating of each tunnel will serve as a spillway tunnel capacity. About 80 percent of both capacities will " ·hen the dam is completed. be provided by the Glen Canyon Unit alone. The powerplant to be constructed at the toe of When completed, Glen Canyon Dam will be the the dam will house seven generating units having fourth highest clam in the world, and second in a total insLalled rapacity of 800,000 kilowatts. height onl:v to Hoover Dam in the United States. ~Ieasures will be taken to protect the Rainbow The units are described below. l\Iodifications in Bridge national monument at the upper reaches some of the designs may result from the definite of the re ervoir. plan studies that will precede construction. Glen Canyon Unit Flaming Gorge Unit Glen Canyon Dam will be on the Colorado The clam for the Flaming Gorge Unit will be River in northern Arizona, about 13 miles down­ at the Ashle.\' site on the Green River, a major stream from the Utah-Arizona State line and 16 Lributary of the Colorado, in northeastem tah miles upstream from Lee Ferry, the dividing point about 6 miles south and 20 miles we t of the corner between the Lower and pper Basins. It is the common to Utah, ·Wyoming, and Colorado. A only one of the authorized dams that will be on the concrete arch dam rising about 495 feet above the Colorado River proper. foundation and about 450 feet above the river Glen Canyon Dam is planned as a concrete arch will be constructed. The reservoir will have a structure that will extend about 700 feet above its c:1pacity of about 4,400,000 acre-feet and an area foundation. It will have a crest length of 1,400 of about 44,000 acres. It will extend upstream feeL. vVhen the 26,000,000 acre-foot reservoir is 94 miles, nearly lo tho town of Green River, full, the water surface area will cover about 153,000 Wyo. About 1,000.000 acre-feet of the reservoir acres and will extend 186 miles up the Colorado capacity will be below the outlet level. River, or nearly to the mouth of the Green River, A powerplan t at the Flaming Gorge Dam will and 71 miles upstream on the San Juan River. have an installed rapacity of 85,000 kilowatts. About 6,000,000 acre-feet of the reservoir capacity will be below the outlet level. This "inactive" ca­ Curecanti Cnit pacity will be useful for sediment accumulation, to The Curecanti l:'nit will develop storage and protect fish, and to increase the power head at power possibilities along part or all of a 35-milc the dam. stretch of a deep canyon section of the Gunnison 3 River above the Black Canyon and below the to"-n acre-feet over a 100-year period, most of the of Gunnison, Colo. sediment being deposited in the inactive section In order to prevent the inundation of propcrt_,­ of the reservoir. The reservoir, when full, will ncar the town, the authorizing legislation proviclrs inundate 13,500 acres and will extend approxi­ that "* * * the Curccanti Dam shall be con­ mately 35 miles up the San Juan River. No structed to a height which will impound not less powerplant is planned for the Navajo Unit. than 940,000 acre-feet of water or will create a reservoir of such greater capacity as can be ob­ Participating Projects tained by a high waterline locat.ecl at 7,520 feel above mean sea level * * *." The act also The eleven participating projects authorized requires that construction shall not be undertaken by Public Law 485 plus the Eden project will be until further engineering and economic investiga­ assisted financially by the storage project.