Wyoming: Glendo Dam

By Discover our Shared Heritage Travel Itinerary Series
Sky view of Glendo Dam surrounded by large craters and water
Glendo is an earthfill dam on the North Platte River, about 100 miles north of Cheyenne, Wyoming. It stands 190 feet high, with a crest length of 2,096 feet. Bureau of Reclamation

Few issues in the arid West are as contentious or complicated as water rights. Wyoming and Nebraska tangled over rights to the North Platte River as early as the 1880s, disputes that on occasion ended up in the U.S. Supreme Court. It took 11 years to resolve one lawsuit, the Supreme Court finally ruling in 1945 that Nebraska was entitled to 75 percent of the North Platte’s flow, and Wyoming 25 percent. When Wyoming’s Glendo Dam was authorized in 1944, it would operate under this Supreme Court decree, but there would be further complications. 

The trouble with the North Platte is its disregard for state boundaries. While the river rises in the snowmelt of the Colorado Rocky Mountains, it flows north into Wyoming, and then curves sharply east, crossing into Nebraska northwest of Scottsbluff. When Glendo Dam was proposed, it was the latest of many dams already ringing the North Platte in Wyoming--Seminoe, Pathfinder, Alcova, and Guernsey (Kortes would be added in 1951; Gray Reef in 1961). Proposed for a site 25 miles downstream from Guernsey Dam, Glendo originally was not intended to add to irrigation development. Its purpose was to help reduce loss of capacity in Guernsey Reservoir due to silting. In addition, it would increase the region’s hydroelectric power by storing water released from upstream powerplants, thereby letting those plants operate year round. 

Although preliminary investigations for Glendo Dam and Reservoir began in 1944, competing state interests held construction up until December 1954. Nebraska feared Glendo Reservoir would reduce flow into Lake McConaughy at Ogallala, while Colorado thought the additional storage at Glendo might be grounds for it to request the use of more water in the state’s North Park region, headwaters of the North Platte. It took an act of Congress, Public Law 841, to reveal just how heated a water question could become in the West. No money would be appropriated for any part of the Glendo project, Congress stated, until a definite plan for water use was agreed upon by the three states and approved by Congress. 

Black and white photo of four women and one man standing on an outdoor stage
On hand for dedication ceremonies on June 9, 1959, were four young women who had been crowned queens in Wyoming, as well as the mayor of the town of Glendo. From left: Jane Waters, dedication queen; Vedana Blomquist, Miss Cheyenne; Marilyn Schipporeit, Miss Casper; Linda Phillips, Miss Wyoming; and

In 1954, the Bureau of Reclamation designed a plan that satisfied all involved, and bids for Glendo Dam were opened on November 9, 1954. Glendo Reservoir, all agreed, would be designed to store 800,000 acre feet of water (one acre foot is enough water to cover an acre of land to a depth of one foot). The capacity then was divided--100,000 acre feet would be used for irrigation; 115,000 acre feet for sediment control; 275,000 acre feet for flood control; and 310,000 acre feet for power production. The agreement, further illustrating the complicated nature of water matters in the West, involved an amendment to the 1945 Supreme Court decree allocating the North Platte’s flow to Wyoming and Nebraska. The amendment provided that although 100,000 acre feet could be stored in Glendo Reservoir for irrigation, only 40,000 acre feet could be used in any one year--15,000 acre feet for Wyoming, and 25,000 acre feet for Nebraska. Additional hydroelectric power would serve both states, as well as Colorado. 

With legal matters settled, the C. F. Lytle and Greene Construction companies began excavation for Glendo Dam in mid-December 1954 and completed the dam in the early fall of 1957. Glendo is an earthfill dam, standing 190 feet high and with a crest length of 2,096 feet. On the south side of the reservoir, nearly a half-mile of dikes were necessary in a low area. Construction also required relocating three miles of Chicago, Burlington, and Quincy Railroad tracks, and four miles of U.S. 87 (now part of Interstate 25), which runs along the west side of the reservoir. Glendo Dam and its powerplant, situated on the North Platte River, are part of the Bureau of Reclamation’s Glendo Unit of the Pick-Sloan Missouri Basin Project.


Visit the National Park Service Travel Bureau of Reclamation's Historic Water Projects to learn more about dams and powerplants.

Last updated: January 13, 2017