Restoration of Glen Canyon

Why was Glen Canyon Dam built?

Originally built for political purposes, Glen Canyon Dam was meant to be a water storage and delivery center for the Lower Colorado River Basin. The Colorado River Compact of 1922 established the legal requirement for the upper basin to deliver 75 million acre feet (MAF) to the lower basin over a ten-year rolling average. A treaty with Mexico in 1944 increased the requirement to 82.3 MAF every ten years. The upper basin Congressional Delegation also pushed for the construction of Glen Canyon Dam as a “cash register” dam, with hydropower revenue being used to help fund dozens of smaller water development projects around the upper basin.

What about Glen Canyon Dam? Does restoring Glen Canyon mean completely removing Glen Canyon Dam?

No. The process of decommissioning Glen Canyon Dam would not involve removing the dam. Glen Canyon Dam is quickly becoming a relic of the past. While there may be too much concrete to fully remove the dam, it will eventually need to be re-engineered in order to preserve the remaining biological integrity of Grand Canyon and the Colorado River. The likely process of bypassing Glen Canyon Dam would involve lowering reservoir levels to what is known as the ‘dead pool’ level (237 feet) and drilling bypass tunnels around the base of the dam, allowing the mobilization of any remaining water and sediment. The dam site will eventually become a major tourist attraction in the region.

What is “Dead Pool”?

Dead Pool is the term used to describe inactive water storage behind Glen Canyon Dam. About 2 MAF of Powell’s 26 MAF storage capacity is considered “dead storage” because the dam currently has no means to release it. During construction of the dam, the river bypass tunnels were filled with reinforced concrete, thus prohibiting any releases from the dam once reservoir elevations dipped below the 237 foot River Outlet Works.

Wouldn’t Glen Canyon be destroyed after years of water inundation?

The current drought and low water levels at Lake Powell reservoir have provided a definitive answer to one of the most common questions: “Isn’t Glen Canyon destroyed?” NO! It is truly remarkable how quickly the reemerging side canyons Glen Canyon are restoring. While decades of submersion have changed the canyons in a variety of ways, much of the original beauty still remains or is rapidly returning. In the upper reaches of the main channel and in many of the revealed side canyons, sediment deposits are being steadily mobilized downstream with seasonal and flash floods, and vegetation and wildlife are returning at astonishing rates. In addition, the bathtub ring is disappearing all around the canyon, and scientists estimate that reservoir evidence on canyon walls could be completely obsolete in as little as three decades. (See evidence of the restoration of Glen Canyon)

Could draining the reservoir harm endangered species, such as bald eagles, which exist in the area now?

Bald eagles do live in the area, but a huge reservoir is not necessary for their survival; many live and thrive along existing southwestern rivers. Eagles and Peregrine Falcons are opportunistic feeders, and can adapt as habitats change. Bald eagle populations in the United States and Canada have grown steadily and their removal from the threatened list is imminent in the next few years. On the other hand, many other endangered species, which are found only in the Colorado River, would be favorably impacted by the restoration of prime habitat in the emerging canyons of the Glen. Currently, many of these native species are in steady decline due to the changed environment brought about by the dam, and policy makers are searching for solutions to prevent extinction.

Won’t Lake Powell fill again?

If above average flows return to the Colorado River Basin, water levels at Lake Powell will begin rising again. However, over the majority of the past decade, basin-wide water demand has drastically exceeded the amount of water delivered by the Colorado River. The effects of a multi-year drought, combined with climate change and overuse have created a 1 million acre foot (MAF) deficit in the Colorado River system annually. Lake Powell and Lake Mead, the two largest reservoirs in the United States, currently hover at 50 percent of capacity and scientists predict that they will likely never fill again. While it is likely that a spike in the hydrograph will raise reservoir levels sometime in the next decade, GCI continues to advocate the Fill Lake Mead First proposal which would shift the majority of water storage downstream to Lake Mead, preserving 500,000 AF of water per year and restoring Glen Canyon in the process.

What is the timeframe for restoring Glen Canyon and a healthy Colorado River?

The short answer: The sooner Lake Powell goes away, the faster Glen Canyon will be restored.

The long answer: In January 2005, Mother Nature had lowered Lake Powell reservoir levels to 37% of capacity and restored hundreds of miles of side canyons in Glen Canyon. Conversely, in the fall of 2010, Lake Mead water levels had fallen below 40 percent, only 10 feet above levels requiring a shortage declaration. Essentially, the time table for Glen Canyon’s restoration is contingent upon Mother Nature and decisions made by water managers and the Colorado River Basin states. A vast amount of research, education and discussion would need to happen before a final decision could be made. However, we emphasize the importance of considering our proposals now before the situation becomes too dire to manage. We urge water managers, policy makers and government officials to study our proposal, engage the public, and provide scientifically credible information to decision makers about a sustainable water supply for future generations.


Who gets their water supply from Powell reservoir?

No straws currently dip into Lake Powell except for Page, Arizona (pop. 8,000) and the Navajo Generating Station. Both of these water users could easily extend their intake pipes into a free-flowing river, should the mission of GCI succeed in the future. The reservoir is essentially a measuring point used to regulate how much water is released into the lower basin annually. If reservoir levels at Lake Powell were lowered, allowing a more natural river to bypass the dam, upper basin water delivery could easily be measured downstream at the Lee’s Ferry gauge and subsequently stored in lower basin reservoirs.

Would the water supply for Colorado River water users be threatened if Powell reservoir were to be drained?

No, it would not. Based upon the Bureau of Reclamation’s own flow data, more than 40 MAF of water has been lost to evaporation since the completion of Glen Canyon Dam. That’s almost twice its storage capacity! According to a report by the Environmental Defense Fund, Upper Basin water use would not be curtailed by draining Lake Powell, and Lower Basin use would be diminished only slightly — an average of 1.2% annually. This analysis used the Bureau of Reclamation’s river modeling program and assumptions.

In other words, the loss of Powell would simply allow for more water in the system. At full pool, Lake Powell loses about 1 MAF of water annually due to evaporation and bank seepage through the porous sandstone. If water were stored in Lake Mead, a much thinner and deeper reservoir, a huge amount of water would be saved each year. The safety of the water supply for Colorado River users is completely dependent upon the way it is stored, managed, and delivered.

Where would we store water without Lake Powell?

There are much better solutions for water storage than Lake Powell, with its huge evaporative loss and environmental degradation. For instance, the Lower Basin is already storing massive amounts of water in underground salt aquifers in Arizona. They are also storing water in off-stream storage facilities such as Diamond Valley, which are much less environmentally destructive and much closer to users in the lower basin. Another option is to shift the majority of water stored at Lake Powell downstream to Lake Mead, which is the main water source for over 22 million people living in the Lower Basin. Water passing the Lee’s Ferry gauge would flow into the more important Lake Mead and be stored as Upper Basin water. Overall efficiency of Colorado River water storage would also be greatly increased by altering the management of reservoirs at the headwaters and decreasing the amount of water stored in wasteful facilities such as Lake Powell reservoir.

How much water does Powell reservoir lose to evaporation and bank seepage?

At full pool, Lake Powell loses an average of 860,000 acre feet of water to evaporation and bank seepage (1 acre-foot is enough to supply two homes for one year). This is equivalent to the annual water usage of Los Angeles!

How long would it take to refill the reservoir if the drought ended now?

Based on projected basin-wide demand spanning average Colorado River inflows in the next few decades, Lake Powell will never refill.

Grand Canyon

Doesn't the existing dam and reservoir protect the Grand Canyon from large, damaging spring floods?

No! Large floods were essential for the evolution of Grand Canyon and they occurred frequently. In fact, elimination of the annual spring floods and sediment flows has caused significant change to the canyon environment, including the loss of a number of native species. Several rare and endangered species have been extirpated from the canyon since the completion of the dam in 1963 and many more are now on the endangered species list. Since the passage of the Grand Canyon Protection Act of 1992, the government has spent millions of dollars annually studying how mimicking natural spring floods might protect existing species.

Allowing the river to flow freely around the dam might allow endangered species to recover, as their natural habitats would quickly be restored A free-flowing Colorado River would replenish necessary sandbars and beaches that have been steadily eroding over the past 50 years, would provide fluctuating water temperatures and levels throughout the year, and would redefine the critical habitats necessary for species survival.

What does the Grand Canyon Protection Act do?

Signed into law in 1992, the Grand Canyon Protection Act (GCPA) directs the Secretary of the Interior to take decisive action in order to protect and preserve the Grand Canyon ecosystem. It specifically reads, “The Secretary shall operate Glen Canyon Dam in accordance with the additional criteria and operating plans specified in section 1804 and exercise other authorities under existing law 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.” In essence, Glen Canyon Dam is to be operated in such a way that the health of the Grand Canyon ecosystem would take priority over other initiatives, such as maximizing hydropower generation. The Adaptive Management Program (AMP) was instituted to provide policy makers with scientific information necessary to fulfill the mandate of the GCPA. However, water and power interests control the decision-making process within AMP. This often leads to only temporary solutions to the ever-growing problem of ecosystem decline in the Grand Canyon.

How much money is spent studying protection options for the Grand Canyon?

About $10 million in tax-payer money is spent annually merely studying the impacts of Glen Canyon Dam on the Grand Canyon ecosystem. Additionally, $10 million is also spent in the Upper Basin annually for Endangered Species Fish Recovery programs. Glen Canyon Dam is responsible for drowning the historical spawning grounds for the native fish in the Colorado River, causing many species to be named on the threatened and endangered list. The release of cold, clear water into the Grand Canyon has caused significant harm to the ecosystem and the wildlife that depends on it, as most of the organisms have evolved over millennia to a warm, sediment-laden river. Because of regulated flows, the Grand Canyon has not experienced a flood in over 50 years, which has also been a detractor from the overall health of the ecosystem.


How much sediment is deposited in the reservoir by the Colorado River?

On average, the equivalent of 30,000 dumptruck loads of sediment is deposited into Lake Powell daily. This is approximately 100 Million tons annually. More than 1 MAF of storage capacity has been lost to date due to sediment deposits.

How long will it take for the sediment that buries much of Glen Canyon and the side canyons to move out?

Scientists predict that without the reservoir, sediment deposits in the main stem of the Colorado would be flushed out within 2-6 years. As we examine behavior over the past decade, it is evident that sediment deposits move out at astonishing rates due to reduced water levels and flash floods.

What happens to all the sediment mobilized around Glen Canyon Dam?

The sediment mobilized around Glen Canyon Dam would move down the river through the Grand Canyon creating new sandbars and beaches, a natural and necessary occurrence prior to the dam being built. The 270 mile-long Grand Canyon has a huge capacity for sediment storage, and is currently sediment bankrupt because of the dam. Sediment not deposited in the Grand Canyon would eventually move into Lake Mead where sediment management is much more feasible and less expensive than at Lake Powell. Upstream conservation and sediment management can assist in minimizing the concern over sediment buildup in Lake Mead. Dams on high volume, high sediment rivers such as the Colorado trap huge amounts of sediment annually. Building more dams upstream to extend the life of downstream dams is not a long-term solution.

What about the toxic sediments?

Naturally occurring heavy metals such as selenium, mercury, boron, lead, and arsenic from upstream sources are all found in the sediment trapped behind Glen Canyon Dam. Additionally, the flooding of Glen Canyon also covered toxic uranium mill tailings near Hite, Utah. The water percolating through this toxic sediment may pose health risks to fish, wildlife, and humans who visit Lake Powell. Management and release of these toxic sediments through the Grand Canyon will require careful consideration to ensure impacts to ecosystems are minimized and that high water quality for downstream users is maintained.

How long will it take for the reservoir to completely fill with sediment?

Scientific studies predict that the reservoir will completely fill with sediment within 300-700 years. However, within 100 years, sediment will reach the River Outlet Works 237 feet above river level, rendering it unsafe in the occurrence of an earthquake or flood. We will eventually be forced to manage the sediment problem and the longer we wait, the more expensive it will be.

Wouldn't Lake Mead silt in faster without Glen Canyon Dam?

Yes. Glen Canyon Dam currently traps over 95% of sediment found in the Colorado River. If the dam were bypassed, and sediment was allowed to flow more freely through the Grand Canyon, Lake Mead would begin to fill faster. However, this fact does not constitute the continued operation of Glen Canyon Dam, but rather speaks to the negative impacts of dams in general. Prior to dam construction, much of the sediment flowing down the Colorado River was captured in the 270 mile corridor of the Grand Canyon, creating beaches and sandbars, which are natural habitats for fish and wildlife in the area. Any remaining sediment would flow to the Colorado River Delta, creating more habitats for wildlife there. Now, only minute amounts of sediment flow through the Grand Canyon, and none reaches the Colorado River Delta hundreds of miles downstream.

Power Generation

Wouldn't power rates go up?

Most power users in the Southwest would not be affected by draining Lake Powell, according to the new report from the Environmental Defense Fund. Glen Canyon Dam produces approximately 3% of the power used in the Four Corners area. There is currently a surplus of power. Most of the power from the dam is purchased for commercial use at heavily subsidized rates. The customers who have received subsidized power from Glen Canyon Dam would pay the market rate, like the rest of us. Most Glen Canyon power users get their power from several sources, which would also serve to lessen the impact.

Would power shortages occur?

Glen Canyon Dam generates less than 1% of the power on the Western Power Grid and the Grid always keeps an excess power capacity of 20% on hand. According to energy experts, losing Glen Canyon Dam as a source of electricity should not create a power shortage because of the excess generating capacity across the Southwest.

How much power does Glen Canyon Dam generate?

Glen Canyon Dam generates 451 avg. megawatts, which is negligible compared to most of the other power generating stations in the region (Navajo, AZ- 2,410 avg. megawatts, Hoover, NV-1,840 avg. megawatts, Four Corners, NM-2,270 avg. megawatts, Jim Bridger,WY-1,749 avg. megawatts, Hunter, UT-1,048 avg. megawatts).

Without Glen Canyon Dam’s “clean” power, wouldn’t the mostly coal-burning power plants have to make up for the lost power, leading to increased pollution?

Glen Canyon Dam does not currently generate “clean” power. While we are correct to say there is no air pollution from the dam, the 186-mile long reservoir (which serves as “fuel” for power generation) has destroyed one of the most incredible regions in the world. Add to that the batteries, feces, and gasoline dumped into the reservoir each year by the myriad of speedboats and houseboats and one may begin to wonder which is the “dirtier” power source. Use of coal and oil fired generators can cause pollution. However, existing environmental restrictions would minimize this impact and many recent improvements in the scrubbing technology for coal power plants have drastically reduced pollution from these sources. Most, if not all, of the power generated by Glen Canyon Dam could be recovered with simple conservation measures and expanded cooperation from power distributors.

Would draining the reservoir make the Navajo Generating Station close?

No. This is a common myth perpetuated by friends of the reservoir. The generating station would only need to extend its intakes down to the river level a few hundred feet below where they are now.

What about Glen Canyon Dam’s “cash-register” function to repay water projects across the upper basin?

To date, about 18% of the reimbursable repayment has occurred through the sale of power, and beneficiaries of the water projects across the upper basin are not being held accountable for the huge costs of these projects. This amounts to an enormous American taxpayer subsidy for a small percentage of upper basin farmers as well as the small percentage of beneficiaries of Glen Canyon Dam’s sub-market rate power.

Additionally, power generation from Glen Canyon Dam has been cut by about 1/3. Because of pre-arranged power delivery contracts, the Western Area Power Administration (WAPA) is currently forced to purchase that 1/3 to meet contracts. The market rate for power in the West is over $.05/ kilowatt hour. WAPA sells its power for just over $.02/kilowatt hour. Power production is negligible under the current flow regime and the economics of continuing to produce power do not make sense.


What about the huge recreation industry at Lake Powell?

Millions of people visit the Lake Powell area every year. A similar number visit the Grand Canyon, which indicates that tourism is not dependent upon a reservoir. There is a thriving recreation industry based on the natural canyons and rivers of the Colorado Plateau, both upstream (Canyonlands National Park, Arches, Bryce, etc), and downstream (Grand Canyon National Park). Located within the “Golden Triangle” of Bryce, Zion, and the Grand Canyon, a restored Glen Canyon would likely receive visitation comparable to these heavily-visited National Parks. A restored Glen Canyon would offer great possibilities for backpacking, leisure non-motorized boating, and wilderness experience. An integrated, sustainable environment could provide for a world resource that would offer high value for future generations. Because the dam and reservoir are temporary, the current Lake Powell motorized recreation-based economy is also. Based upon the economic benefits accrued for the region surrounding the Grand Canyon, similar economic benefits would be derived for the communities surrounding a restored Glen Canyon.

What about the economic impacts to the region, including Page, AZ?

Under our proposal, the economic benefits to the Glen Canyon region would actually increase to a level comparable to that of Grand Canyon National Park. Additionally, economic benefits would be distributed more evenly among the communities surrounding Glen Canyon, including Escalante, Bluff, Blanding, Boulder, Kanab, Mexican Hat, Hanskville, Kayenta, and the Navajo Nation. Page, which is subject to the fluctuation economic benefits of a fluctuating reservoir, would evolve into a major access point to Glen Canyon for land-based uses.

Page was first built as a service camp for the workers who built the dam. When the dam was completed, most of Page’s residents left, while the remaining residents adapted to the new motorized-recreation economy. Upon the restoration of Glen Canyon, Page will adapt once again to a sustainable non-motorized recreation based economy and function as the access point to a major attraction in the West, the Glen Canyon Dam site. Also, because of the scientific importance and magnitude of restoring the vast Glen Canyon ecosystem, Page would become the headquarters for dozens of long-term scientific programs from around the world, and an example of positive change.

Current economic benefits of the reservoir are short-term and unsustainable. Restoring and protecting Glen Canyon would ensure a sustainable, long-term economic foundation for Page, as well as the other access communities throughout the region.

What would the impacts on river running be without Glen Canyon Dam?

There is immense pressure for river running opportunities on the Colorado River through Grand Canyon. There is currently a 20 year waiting list for private boat trips in the Grand Canyon. A free-flowing river through Glen Canyon would alleviate some of this pressure by re-introducing 186 miles of the Colorado River.

Would the river running season in Grand Canyon be shortened without regulation by Glen Canyon Dam?

It needn’t be. Before Glen Canyon Dam was built, river runners successfully ran trips throughout the year. In fact, some of the lowest flows on record, which presented significant problems for river runners, occurred after the dam was built as the reservoir was filling. In the early 1970s the dam shut the river down to around 1,000 cubic feet per second (cfs), and during the late 1980s the dam quite often reduced flows to 3,000 cfs. During 1983, releases approached 100,000 cfs. Yet throughout both of these extremes, commercial rafting continued. We don’t need a dam to run a river; people run free flowing rivers all over the world. Cataract Canyon is largely unregulated, and yes, it gets exciting when spring run-off is high. But it is still run commercially. How would a free flowing Colorado River affect river running in Grand Canyon? For one thing, it would be more real.

Wouldn't the world class trout fishery below Glen Canyon Dam be lost?

This trout fishery exists because of the dam, and would likely disappear if a natural, warm river returned. However, natural habitats for endangered native fish – which used to inhabit this stretch of river – would be restored. The trout fishery has been an important part of the Northern Arizona economy. However restoration of the river would provide for a self sustaining environment in Glen and Grand Canyon that is far more valuable. Currently, trout prey upon the endangered fish species in the Colorado River, which has caused the government to spend millions annually on schizophrenic efforts to move, remove, and replace native fish populations in the area. This program is simply not working.

GCI’s Position - Continued

Where are your facts?

Glen Canyon Institute has stated its goal, but we recognize that all the information to answer questions about restoring Glen Canyon is not yet in hand. We rely heavily upon data produced by the Bureau of Reclamation, United States Geological Survey, and the Department of Energy. Additionally, significant scientific evidence obtained by the Glen Canyon Environmental Studies Program and the Grand Canyon Adaptive Management Program reinforce our claims and demonstrate the huge destructive costs of Glen Canyon Dam on the downstream environment.

Glen Canyon Institute has conducted an initial Citizen’s Environmental Assessment (CEA) to examine the opportunities, costs and environmental impacts of restoring Glen Canyon. We have also funded a number of studies aimed at better understanding water loss, bank seepage, and hydropower effects of Glen Canyon Dam as it relates to the Fill Mead First project.

Why is the Environmental Assessment so important?

If Glen Canyon Dam and Lake Powell were proposed today, an Environmental Assessment followed by an Environmental Impact Statement (EIS) would be required by the National Environmental Policy Act (1970). We believe the majority of Americans would support restoring Glen Canyon if all the facts were known; as such, we believe such a study would be in the public interest.

Wouldn't a Citizen’s EA be biased since you've already taken a position against the reservoir?

We urged the government to do a complete environmental analysis of the impacts of Lake Powell and to provide objective information. Since this project was refused for a number of years, Glen Canyon Institute secured private funding in order to hire various unbiased scientists to conduct such a review. The science and documentation are available to the public on this website. We believe the facts speak for themselves.