Glen Canyon Dam 

and Powerplant 

Lake Powell 

Lake Powell 

Glen Canyon Dam impounds Colorado River water 

to form Lake Powell, one of the most popular and 

scenic lakes in the world. When full at 3,700 feet 

( 1,100 meters) above sea level, Lake Powell is 186 

miles (299 kilometers) long and has an incredible 

1,960 miles (3,150 kilometers) of winding shoreline. 

The lake and more than one million acres (400,000 

hectares) of desert and canyon country provide 

tourists with some of the most spectacular 

recreational hot spots found anywhere in the nation. 

Named after Major John Wesley Powell, who in 

1869 successfully led the first expedition 

down the Colorado River through the Grand 

Canyon, Lake Powell enables many people to view 

cultural resources and natural wonders that were 

previously inaccessible. 

Scenic Lake Powell 

Lake Powell started filling on March 13, 1963 . In 

1980, 17 years after the diversion tunnel gates were 

closed, Lake Powell filled completely for the first 

time. Today, millions of people depend on the waters 

of Lake Powell to sustain life. To meet the intended 

purposes, the elevation of Lake Powell must fluctuate . 

During spring runoff, May through July, the lake 

normally rises. During the remainder of the year, the 

lake elevation drops, leaving a visible ring along the 

shoreline. How much or how fast the lake lowers 

depends on water deliveries to the Lower Basin 

states of Arizona, Nevada, and California; how 

much water is carried over from the previous year; 

and how much runoff water flows into Lake Powell 

from the Colorado River system. During periods of 

extended drought, the elevation of Lake Powell could 

drop by more than 200 feet ( 60 meters) below its 

maximum elevation. 

Waterfall in No-Name Canyon 

Beach at Wahweap 

Recreation 


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The Glen Canyon National Recreation Area, 

established in 1972 and managed by the National 

Park Service (NPS), attracts about 2.4 million visitors 

annually. The hundreds of miles of Lake Powell 

shoreline provide opportunities for hiking, camping, 

swimming, boating and fishing . Lake Powell 

supports some of the nation's finest lake fishing, 

featuring bass, bluegill, green sunfish, walleye, black 

crappie, northern pike and catfish. A blue-ribbon 

trout fishery, located in the 15 miles of river from 

the dam to Lees Ferry, was developed after the dam 

was built. 

Some of the most spectacular scenery found 

anywhere in the world can be seen when rafting the 

Colorado River through Glen and Grand Canyons . 

Rafters can view the natural beauty of geologic 

formations, observe wildlife, such as mule deer, 

desert bighorn sheep, hundreds of species of birds, 

and see ancient Native American ruins, all while 

experiencing the thrill of a white-water raft trip . 

Antelope Marina 

The Carl Hayden Visitor Center, located 700 feet 

(213 meters) above the Colorado River, overlooking 

Glen Canyon Dam and Bridge, accommodates 

between one-half to one million visitors annually. 

Tours of the dam and powerplant, park ranger 

presentations, exhibits, audio-visual programs and 

an educational bookstore are available. 
Hydroelectric Power 

To generate electricity at a dam, water must be in 

motion. This is called kinetic (moving) energy. 

When flowing water turns the blades in a turbine, 

the energy form is changed to mechanical energy. 

The turbine turns a generator rotor which then 

converts the mechanical energy into another energy 

form - electricity. Since water is the initial source 

of energy, it is called hydroelectric power, or 

hydropower for short. 

Glen Canyon Powerplant has eight electric generators 

that can operate at a combined output of 1,320,000 

kilowatts. Each of the eight turbines requires about 

4,000 cubic feet per second (117 cubic meters 

per second) of water flow from Lake Powell to 

operate the generator at its full capacity. With all 

eight generators operating at full output, about 

15 million gallons (57 million liters) of water passes 

through the powerplant's penstocks each minute. 

Glen Canyon Powerplant produces five billion 

kilowatt-hours ofhydroelectric power a year. This 

electricity goes to help supply the electrical needs of 

about 5.8 million customers. The power is marketed 

Transmission towers and switchyard on canyon rim 

by the Western Area Power Administration and is 

sold to municipalities, rural electric cooperatives, 

Native American tribes and governmental agencies 

in Wyoming, Utah, Colorado, New Mexico, Arizona, 

Nevada and Nebraska. Interconnecting transmission 

lines, both private and public, carry the power to 

major metropolitan areas and to rural areas in the 

West. Revenues earned from the sale of the power 

from Glen Canyon Powerplant and other Colorado 

River Storage Project (CRSP) facilities are used to 

pay for the construction, operation, and maintenance 

of the CRSP water storage units. Power revenues are 

also used to help pay for irrigation construction costs 

of CRSP participating projects. 

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Generators, Glen Canyon Powerplant 

Management 


Glen Canyon Dam and Powerplant are operated 

and administered by the Bureau of Reclamation. 

Address inquires to: 

Manager, Glen Canyon Field Division 

Bureau of Reclamation 

P. 0. Box 1477 

Page, Arizona 86040, (928) 645-2481 

For more information on the Bureau of 

Reclamation visit: www.usbr.gov 

The Glen Canyon National Recreation Area 

is managed by the National Park Service. 

For information contact: 

Superintendent, Glen Canyon National 

Recreation Area 

P.O. Box 1507 

Page, Arizona 86040, (928) 608-6200 

www.nps.gov/glca 

To learn more about recreational opportunities 

on federal land, visit www.recreation.gov 

Tours 

Tours of Glen Canyon Dam and Powerplant 

are offered year-round at the Carl Hayden 

Visitor Center. Visitors to the dam must go 

through security before beginning the tour. 

The visitor center is open daily except 

Thanksgiving, Christmas, and New Year's days. 

Regulations and Safety: Always check with 

state, U.S. Coast Guard, and NPS rangers for 

current information of boating and safety 

regulations within the Glen Canyon 

Recreation Area which includes Lake Powell. 

The mission of the Bureau of Reclamation 

is to manage, develop, and protect water 

and related resources in an environmentally 

and economically sound manner in the 

interest of the American public . 

A

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Colorado River Storage Project 


Glen Canyon Dam is the key unit of the Colorado 

River Storage Project (CRSP). From Lake Powell, 

Colorado River water flows through the Grand 

Canyon in Arizona to Lake Mead behind Hoover 

Dam. The CRSP was authorized by Congress in 

1956. Other water storage units of the CRSP 

include the Wayne N. Aspinall Unit on the 

Gunnison River in Colorado (Blue Mesa, Crystal, 

and Morrow Point Dams); Navajo Dam on the San 

Juan River in New Mexico; and the Flaming 

Gorge Unit on the Green River in Utah and 

Wyoming. CRSP participating projects, also 

authorized by Congress, deliver irrigation water to 

farms and provide municipal and industrial water 

to communities. The purposes of the CRSP are to 

Colorado River Basin 

regulate the flow of the Colorado River; provide for 

storage and delivery of water for irrigation, municipal, 

industrial, and other beneficial purposes; provide for 

flood control; generate electrical power; and improve 

water quality. The CRSP also provides for recreation 

and improves conditions for fish and wildlife. 

Bird's eye view of Glen Canyon Dam 

Highscalers descending canyon wall downstream from 

Glen Canyon Dam 

Glen Canyon Dam 


Glen Canyon Dam, completed in 1964, was built 

and is operated and maintained by the Bureau of 

Reclamation. The construction of the dam, built in 

a virtually inaccessible area on the Colorado River 

eight miles below the Utah-Arizona border, is one 

of the major engineering and construction 

achievements in the United States. 

Investigations for a damsite on the Colorado River 

began as early as 1920 when the lower region of Glen 

Canyon was first considered. The final site for Glen 

Canyon Dam was carefully examined and selected by 

Colorado River Bridge construction, February, 1958 

First bucket of concrete 

a group of Reclamation engineers and geologists 

working from 1946 to 1948. Factors considered in 

selecting the dam site were: the proposed reservoir 

basin could hold a large volume of water, the 

canyon walls and bedrock foundation were stable 

and strong enough to safely support a tall dam, and 

a good source of rock and sand for making concrete 

to build the dam was located close by, on Wahweap 

Creek, just eight miles from the construction site. 

On October 15, 1956, President Dwight D. 

Eisenhower pushed a button from the White House 

triggering the initial blast that signaled the start of 

construction. The prime construction contract was 

awarded to Merritt-Chapman and Scott in April 

1957. Workers began excavating tunnels for 

re-routing the river, blasting to bedrock for the 

foundation and carving into the canyon walls for 

the abutments of the dam. The canyon was actually 

shaped to fit the dam. Concrete placement began 

in June 1960 and continued 24-hours a day until 

the final bucket of concrete was placed three years 

later, on September 13, 1963. In all, it took over 

400,000 buckets, each holding 24 tons of concrete, 

to build the dam. 

Glen Canyon Dam is the second tallest concrete-arch 

dam in the United States. The benefits provided by 

the dam are numerous and vital to life in the Western 

United States. The dam stores approximately 26.2 

million acre-feet (32.3 billion cubic meters) of 

Colorado River water that is critical to the survival 

of cities, industries, and agriculture throughout the 

West and Mexico. Hydroelectic power produced by 

the dam's generators helps meet the electrical needs 

of the West's population. Lake Powell, the reservoir 

behind the dam, is not only an important recreation 
area, but it serves as a "savings account" of 

water that can be drawn upon during dry years. 

Page, Arizona, a thriving desert town, began in 1957 

as a construction camp for the thousands of men and 

women and their families associated with the 

construction of Glen Canyon Dam. The town was 

named after John C. Page, the Commissioner of 

Reclamation from 1937 to 1943 . At the peak 

of Glen Canyon Dam construction, Page had 

approximately 7,500 residents . 

Damsite , May 1963 

Damsite , July 2004 

First Lady, Mrs . Lyndon B. Johnson dedicates Glen Canyon 

Dam , September 22, 1966 

Page, Arizona in 1983 with Lake Powell at full elevation of 

3,700 ft (1,128 m) 

Colorado River Storage Project 

Hydroelectric Power Customers 

D Customer Area 

II City Customers 

Estimated customers served - 5.8 million 

Glen Canyon Unit Data 


Glen Canyon Dam 

Type ----------------------------------Concrete arch 

Construction period---------------- 1957-1964 

Height above bedrock-------------- 710 ft (216 m) 

Height above original 

river channel ---------------------- 583 ft (178m) at 

lowest point Crest length 

(arc at axis of dam)---------------1 ,560 ft (475 m) 

Volume of concrete----------------- 4,901,000 cu yds (3 ,750 ,000 m3) Initial cost of dam, powerplant 

and appurtenant structures _______ $245 million 

Glen Canyon Powerplant 

Generating Units-------------------- 8 

Installed capacity ___________________ 1,320,000 kW 

Lake Powell 

Water storage begins--------------- March 13, 1963 

Completion of initial filling _______ June 22 , 1980 

Total capacity when full at 

elevation 3,700 ft _________________ 26.2 maf 

(32.3 billion m3) 

Length of lake --------------------- 186 miles (299 km) 

Depth of water at dam _____________ 560 ft (171m) 

Milestones 

Construction authorized----------- April 11, 1956 

First construction contract 

awarded (right diversion tunnel 

excavation)------------------------- October 1, 1956 

Diversion of Colorado River 

around dam site ___________________ February 11 , 1959 

First bucket of concrete____________ June 17, 1960 

Last bucket of concrete____________ September 13, 1963 

First power generation _____________ September 4, 1964 

Dedicated by Mrs . Lyndon B. 

Johnson-----------------------------September 22, 1966 
Environmental Issues 


As a result of the construction and operation of 

Glen Canyon Dam, the Colorado River ecosystem 

below the dam changed significantly from its 

pre-dam natural character. Before the dam was 

built, the Colorado River was a sediment-laden 

river that fluctuated in flow according to the 

seasons, rainfall, and inflows from side canyons. 

Now, the water released from the dam runs clear 

and cold without the spring time floods that once 

transported sediment, built beaches, and provided 

habitat for native species. Downstream from the 

dam, a new ecosystem emerged consisting of 

a mixture of native and non-native plant and 

animal communities. 

Following its construction, Glen Canyon Dam 

was operated to meet the fluctuating demand for 

electrical power. Since the need for power varies 

greatly depending on the time of day and season, 

releases of water from Glen Canyon Dam were 

adjusted hourly to respond to changes in 

electrical demand. 

Recognizing that this type of operation was 

impacting the downstream Colorado River 

environment, Reclamation launched the Glen 

Canyon Environmental Studies Program in 1982. 

By the late 1980s, sufficient scientific evidence 

was gathered to demonstrate that significant 

impacts on the downstream environmental and 

cultural resources were occurring as a result of 

daily fluctuating water releases from the dam. 

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fPetroglyphs in Glen Canyon 

These findings led to a July 1989 decision by the 

Secretary of the Interior directing the Bureau of 

Reclamation to prepare an environmental impact 

statement (EIS) on the operation of Glen Canyon 

Dam. In addition, Congress enacted the Grand 

Canyon Protection Act of 1992 . This act requires the 

Secretary to operate Glen Canyon Dam consistent 

with existing law and in such a manner as to "protect, 

mitigate adverse impacts to, and improve the values 

for which Grand Canyon National Park and Glen 

Canyon National Recreation Area were established, 

including but not limited to natural and cultural 

resources and visitor use." The EIS would provide the 

necessary information and analysis for a Secretarial 

decision on how to best operate the dam to balance 

the competing interests of hydropower generation and 

downstream resource protection. 

The resulting EIS was prepared with an unprecedented 

amount of scientific research, public involvement, 

and stakeholder cooperation. Revenues from power 

generation funded the environmental studies and 

preparation of the EIS at a cost of about $104 million 

over an approximate 13-year period. Seven public 

hearings were held and more than 33,000 public 

comments were received, reflecting the national 

attention and intense interest in the EIS process . 

The 1996 EIS Record of Decision (ROD) established 

new dam operating criteria that constrained daily 

minimum and maximum releases from Glen Canyon 

Dam and limited the hourly rate at which the flows 

could fluctuate . The ROD also established the 

Adaptive Management Program to advise the 

Secretary of the Interior as new scientific information 

from monitoring and research efforts becomes 

available . Both the EIS and adaptive management 

processes demonstrate the value of a cooperative, 

integrative approach in dealing with complex 

environmental issues, and resulted in an inclusive 

stakeholder process that provides input on 

the operations of Glen Canyon Dam today. 

Biologists checking fish populations 

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Juvenile endangered humpback chub 

Horseshoe Bend, Colorado River, downstream from 

Glen Canyon Dam 
Frequently Asked Questions 

Which is talle~; Glen Canyon Dam or Hoover Dam? Which 

is large~; Lake Powell or Lake Mead? 

Hoover Dam, which stands 726 feet (221 meters) tall , is 16 feet 

(4.9 meters) taller than Glen Canyon Dam which stands 710 feet 

(216 meters) tall. When full , Lake Mead, which holds 28.5 

million acre-feet (35.2 billion cubic meters) of water, is larger 

than Lake Powell which holds 26.2 million acre-feet (32.3 

billion cubic meters) of water when full. 

Was anyone buried in the concrete during construction of 

Glen Canyon Dam? 

During construction of Glen Canyon Dam, 18 workers died in 

various kinds of accidents. All of the bodies were recovered and 

accounted for and no one was buried inside the dam. Because of 

the construction techniques used to build the dam, it was 

impossible for a worker to be buried in the concrete. The 

enormous quantity of concrete used could not be placed all at one 

time. Instead, the dam was constructed as a series of concrete 

blocks, some as large as 60 by 210 feet (18 by 64 meters) . 

Many buckets of concrete were dumped one at a time 

to fill each block. As each bucket load was released, workers 

smoothed out the concrete with special equipment. Once the 

concrete was placed within each block, the maximum depth 

of fresh concrete that a worker could have fallen into was only 

12 inches (30 centimeters). It was not possible for someone to 

become buried in such a shallow depth of concrete. 

Why is it so cold inside the dam? 

The water that flows into Lake Powell originates as snowpack 

high in the mountains of Colorado. This icy water flows into the 

lake where it is so deep it cannot be warmed by the sun. As a 

result, the temperature of the water deep below the lake's surface 

is about 44 degrees F (7 degrees C) year-round, keeping the dam 

cold inside. The temperature inside the dam remains fairly 

constant at 50 degrees F (10 degrees C) year-round. 

What is the purpose of the rock bolts in the canyon walls? 

Hundreds of rock bolts were installed by high scalers to 

reinforce the canyon walls and prevent rock slabs from falling. 

The high scalers, suspended from long cables attached to 

windlasses on the rims of the canyon walls , drilled holes from 

15 to 75 feet (4.6 to 23 meters) into the Navajo sandstone, 

inserted the bolts with expansion anchors, then forced concrete 

grout around them to secure them within the walls . 

How much waterfrom Lake Powell is lost into the atmosphere 

because of evaporation? 

About two to three percent of the lake's water evaporates into the 

atmosphere each year. However, this water returns to the earth in 

the form of precipitation, so it is not lost, it is recycled . 

How much water seeps through the dam? 

The sandstone walls of Glen Canyon contain natural fractures that 

allow water from Lake Powell to seep through them and into 

various tunnels in the dam. About 2,600 gallons per minute 

(9,841 liters per minute) seep into the dam (not a large amount of 

water for a structure this size). All water that seeps into the dam is 

routed through measurement weirs, then diverted to troughs at the 

base of the dam and discharged to the river below. No dam or 

foundation for a dam is absolutely impervious to seeping water. 

If the seepage is controlled to prevent erosion, it is not only 

tolerable, but normal. 

Is water in Lake Powell absorbed into the rock of the 

canyon walls? 

As Lake Powell filled , water absorbed into the rock of the 

canyon walls. As the reservoir level drops during periods of 

drought, most of the absorbed water returns to the reservoir. 

Known as "bank storage," the availability of this water for use 

during drought periods is difficult to quantify. 

What are the benefits of using hydroelectric power? 

Hydroelectric power is a clean renewable form of energy that 

does not pollute the air, land, or water. Hydroelectric powerplants 

have low failure rates, low operating costs, and are very reliable. 

In addition, the use of hydropower reduces our dependence on 

other more environmentally polluting energy sources. 

Can the electricity produced at Glen Canyon Powerplant be stored 

for use at a later time? 

One drawback to electricity is that it cannot be stored for future 

use. Consequently, a utility company must have the capacity to 

provide power instantly to meet public needs . But since power 

demand varies greatly during the day and night, this job becomes 

quite complex. Hydroelectric generators can be started and 

stopped quickly, so hydropower is more responsive than other 

energy sources in meeting changing power demands. 

How many kilowatt-hours of power does Glen Canyon Dam's 

powerplant produce annually? 

Approximately five billion kilowatt-hours. 

How much coal would it take to produce annually the same amount 

of power? 

It would take 2.7 million tons of coal or 8.6 million barrels of oil 

to generate the same amount of power that Glen Canyon Dam's 

generators produce in one year. By using water instead of fossil 

fuel, Glen Canyon Dam Powerplant eliminates seven million 

pounds of carbon dioxide emissions each year. 

Why does the lake look so blue and the river below the dam 

look so green? 

Lake Powell's deep blue color results from the fact that it is a 

relatively clear body of water that reflects the color of the sky. The 

river below the dam looks green due to the feathery algae called 

cladophora that thrives in the river. This algae forms the basis of a 

highly productive food chain and is an important source of nutrients 

for many species living below the dam. 

Are there tunnels inside Glen Canyon Dam? 

Yes. Many long and narrow corridors called galleries were built 

inside the dam to allow for inspection of various inner sectors. 

These galleries are not open to the public. 

How is the Colorado River controlled? 

The Colorado River is administratively controlled by numerous 

statutes, compacts, decrees, and a treaty with Mexico, 

collectively referred to as the "Law of the River." In 1970, the 

Criteria for Coordinated Long-Range Operation of Colorado River 

Reservoirs was prepared in accordance with these formal 

regulations to form the rules by which the Colorado River 

reservoir system is operated. A plan is prepared each year by the 

Bureau of Reclamation to guide the operations of the Colorado 

River Basin reservoirs. 

Does the elevation of Lake Powell drop during experimental 

high flows? 

The level does decrease by a few feet in the short term, but by the 

end of the water year the level is unchanged. 

Are there any federally-listed endangered species living in the Grand 

Canyon below Glen Canyon Dam? 

Yes. Federal endangered species living in the Grand Canyon 

below the dam include the humpback chub, razorback sucker, 

southwestern willow flycatcher, peregrine falcon, and the 

Kanab ambersnail. 

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Night view of jet tubes during the March 2008 high-flow test 

Sandy beach in the Grand Canyon Researchers gather data during the 2008 test flow 
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Rafters at Lees Ferry Riding the waves at Padre Bay, Lake Powell