A grand experiment brings spring floods back to the Canyon
Upstream water users are wary of the impact on vital water and power supplies as concern for the environment downstream from big federal dams begins to play a greater role in their operation.
The roar of floods returned this spring to the Grand Canyon as a surge of water rushed down the Colorado River from Glen Canyon Dam, where the flow has been harnessed for more than three decades.
The week-long flood was no threat to Biblical high-water marks, but it was a history-making event nonetheless.
The significance lies in the purpose of the flood, created by a planned, experimental release of water from the dam. For the first time, the environment was the intended benefactor of such a release, meant in this case to test the ability of an artificial flood to restore ecosystems in the Colorado River.
Since its completion in 1963, Glen Canyon Dam, like most large western dams, has been operated primarily for water storage. Generation of electricity has been the secondary purpose, while protection of natural and cultural resources downstream has trailed the list of priorities.
Today the priorities seem to be shifting, driven by such forces as scientific research and federal policy. For example, the Grand Canyon Protection Act of 1992 mandated that the operation of Glen Canyon Dam be re-evaluated to minimize any harmful effects on downstream resources.
U.S. Interior Secretary Bruce Babbitt said the test flow marked the beginning of “a new era for ecosystems, a new era for dam management, not only for the Colorado but for every river system and every water-shed in the United States.” It is the Interior Department’s Bureau of Reclamation (USBR) that operates federal dams like Glen Canyon.
But what is the potential local impact of such a change? Regardless of whether Babbitt’s statement is more political exaggeration than accurate prediction, a major first step has been taken, so the question remains. In the case of the Colorado River, the answer depends on whom one asks.
Those in favor of regular flood flows say helping the river will be the only real impact, while water users in upper basin states have serious concerns about water storage and hydropower.
THE RIVER’S LIFE IS A BEACH
Research on the downstream impact of Glen Canyon Dam, coordinated largely by the USBR’s Glen Canyon Environmental Studies (GCES) office, was a driving force behind the recent experimental flood. The National Park Service and the U.S. Geological Survey have also been prominent participants in studies of the river and its ecosystems.
“The fact is, we’ve spent 13 years convincing folks of the need for [an experimental flood],” says David Wegner, GCES program manager. “The science is there to support it.”
The GCES research has focused on the section of the Colorado River that runs from Glen Canyon Dam near the Utah-Arizona border, through the Grand Canyon National Park and into Lake Mead at the Nevada border. The status of the river’s sandbars or beaches, vital as habitat for plants and wildlife and as stopping points for the estimated 22,000 river users each year, has been the key issue.
Researchers say that before construction of Glen Canyon Dam, the river constantly renewed and reshaped the beaches through the deposit of sediment and spring flood flows generated by snow melts in the basin. The river carried an average of 66 million tons of sediment to the head of the Grand Canyon each year before the dam was built.
That average dropped to around 91,000 tons per year after construction of the dam. So, to a great extent, the river has been denied both the building materials and the forces necessary for creating beaches.
In the meantime, existing beaches have been steadily eroded, and much of the sand has settled into the middle of the river channel.
Aside from the loss of habitat and campsites, the erosion has also threaten archaeological sites within the Grand Canyon. Researchers believe that the canyon walls containing these sites could eventually wear down and collapse without beaches to buffer them from the water’s action.
The intent of the experimental flood, therefore, was to simulate the heavy spring flows of pre-dam days and to move sand from the river channel back to the shoreline.
The experiment began on March 22, four days before the actual water release. Operators held flow through the dam at a steady 8,000 cubic feet per second (cfs) – about 4,000 cfs below normal – as researchers took “before” photos of river conditions.
On March 26, the water flow was stepped up to a peak of 45,000 cfs – a rate that would fill Chicago’s 110-story Sears Tower in just 17 minutes.
Since turbines in the dam’s power plant can handle a maximum flow of 30,000 cfs, operators opened four 8-foot-wide overflow tubes near the base of the dame to raise the flood to its peak level.
This release of water bypassing the power plant was a key to the concerns of upstream water users.
Early results are positive
After 7 days, flow through the dam was slowly downramped to 8,000 cfs, where it was held for several days to allow researchers to look at post-flood conditions. By mid-April, the normal flow of around 12,000 cfs was passing through the dam’s turbines.
Initial word from the USBR and the Interior Department has been that the test was successful. “The beaches and species habitat through the Grand Canyon appear to have been significantly restored,” Babbitt said in an April press conference.
“We have been particularly pleased by the sheer volume of beach creation, which appears to have added as much as one-third more sand beaches throughout the river and canyon.”
Researchers also found that the flood created numerous backwater channels along the river, channels they hope will serve as havens for endangered fish like the humpback chub and razorback sucker. These species require the warm water habitat that such channels provide.
Warm water has been drastically limited since the dam’s completion. The river that once ran warm and muddy through the Canyon is now cold and clear once it is released from the depths of Lake Powell free of sediment. Rainbow trout, a non-native species, thrive in the cold water but several native species have vanished.
Though early results from the test flood show significantly restored beaches and backwater channels, USBR officials and others studying the test say it is too soon to judge its overall impact. A final report is not expected until September.
“It will be a long-term process to really tell the effects of the experiment,” says David Simon, southwest regional director for the National Parks and Conservation Association. “You’re not going to see black and white changes overnight.”
WATER STORAGE AND
HYDROPOWER ARE KEY ISSUES
The first blast of water from Glen Canyon Dam’s overflow tubes was the culmination of much negotiation and planning by federal officials and various interests. Water users above the dam, trout fishermen, environmental groups, Native American tribes and river expedition companies were some of the “stakeholders” who spent at least two years hammering out a basic approach to the test flow.
“The decision to do the flow was actually built on a broad consensus basis,” says Mark Schaefer, the Interior Department’s deputy assistant secretary for water and science. “Before it ever happened, there was a strong consensus that this was a very worthwhile experiment.”
Not everyone has been easily convinced, however. Perhaps the loudest protests came from Colorado, Wyoming, Utah and New Mexico, the four upper basin states that have a complicated and dependent relationship with the Colorado and its system of dams and reservoirs.
In simple terms, these states no desire to see major tampering with. the river’s carefully regulated flow.
“Because of the critical nature of our systems out here, they’re highly protected, emotionally protected,” says Wayne Cook, executive director of the Upper Colorado River Commission in Salt Lake City. The federally mandated commission includes one representative from each upper basin state, as well as one representative from the federal government.
“[In the West], if we don’t store water in a reservoir, it will flood us when it rains or not show up when we need it,” Cook says. “Out here, we’re totally dependent on the controlled storage of water supply.”
This storage is provided largely by reservoirs at the river’s 14 federal dams authorized by the Colorado River Storage Act of 1956. The act also authorized several “participating projects,” including smaller dams, canals and transmountain pipelines, along the river and its tributaries. These projects are the means by which the river’s water is actually used.
Many of the projects enable the irrigation of vast agricultural lands or the transport of water to growing cities like Salt Lake City and Albuquerque, N.M., which use the water to supplement local supplies, according to Cook. In Denver, the water supply is supplemented through independent systems that function much like the participating projects.
Each year, the upper basin states are allocated 7.5 million acre feet of water for their needs, according to a compact signed with the lower basin states of Arizona, Nevada and California. The upper states must in turn release a minimum of 7.5 million acre feet through Glen Canyon Dam for the lower basin states to use.
“Seventy-five years of history have taught us that we can probably only depend on 6 million acre feet or less in the upper basin [each year],” Cook says. “The primary purpose of [Lake Powell] is to conserve water because that’s the only way we can guarantee our release to the lower basin.”
It is a rather tricky situation, many maintain, because the Colorado’s water is actually overallocated.
“They divided up a pie that is, in effect, smaller than the states thought,” says Simon. “There are more claims on water in the Colorado River than there is water. All of the major western cities have designs on more water, and there aren’t many places to get it … There’s a fixed amount that comes down that river every year.”
So any significant spill of water in the system of dams and lakes is an issue. But, more importantly, the upper basin states have been concerned with the timing and precedent of the test flood and its potential effect on power revenues.
“To allow anything that will let [the USBRI release water any time it wants, under any [water level] conditions, is a really serious matter,” Cook says.
Revenues from power sales pay the dams’ operating costs, as well as around 95 percent of the participating projects’ costs. Any remaining revenue goes toward the original expense of building the dams and projects.
Around 80 percent of the power is sold, at cost, to 110 different entities represented by the Colorado River Energy Distributors Association (CREDA). CREDA’s members many of whom are individual or associated municipal utilities, then sell the power at cost to retail customers located in several western states.
The concern with a flow that bypasses Glen Canyon’s power plant is that the released water is not available to generate power later in the year, when most of the water guaranteed to the lower states has been released. Revenues would theoretically decline, so federal operators would have to raise wholesale rates to continue paying the cost of operating the dams and participating projects.
“The reality of it is that whatever the costs are, the government is going to collect it from somewhere,” says Joe Hunter, CREDA’s executive director.
“Glen Canyon Dam drives these rates, because it has 75 percent to 85 percent of the power production. If you make a change at Glen Canyon, that affects the entire system.”
CREDA members would in turn have to set higher rates for their several million customers, whose rates in the past have been relatively low. That is a step they would rather not take in today’s increasingly competitive power market, Hunter says.
“The value of federal hydropower on the Colorado River is becoming a little tentative,” he says. “The days when this was just incredibly inexpensive power are long-gone.”
The USBR has estimated a $2.7 million loss in revenue from Glen Canyon Dam this year because of the test flow, according to Hunter. It has not yet been determined whether the dam’s wholesale rates will be increased to make up for that loss.
“They went to extraordinary lengths to put this thing together,” he says. “The one thing they didn’t do was determine who will pay for it. We’re still a bit irritated by that.”
NO SPECIFIC PLANS SET FOR
This spring’s experimental flood was more a temporary truce than a final settlement of the debate on such releases. It was driven by a convergence of factors like scientific data, federal will, a wet water year and the unique nature of the Grand Canyon, factors that may not be present at other dam sites or in other years.
“The secretary says it’s a new era,” Cook says. “That’s hogwash.”
The upper basin states agreed to the test flow only after specific criteria for future releases were negotiated, and they insist that water storage and power needs still have the highest priority via the Colorado River Storage Act, according to Cook.
“We were more concerned about how this happens over the next 50 years than what happens this year,” he says of the experimental release.
Therefore, the states and the Interior Department agreed to consider future beach-building releases from Glen Canyon Dam only when:
* a sufficient amount of sand has been eroded from beaches and deposited in the river channel; and
* Lake Powell is full or near-full and the upstream runoff sufficient, so that a spill of water past the dam’s power plant would occur anyway.
“It becomes, if you will, an attempt to do a managed spill, rather than let water spill unmanaged,” Cook says.
These conditions did not actually exist this spring during the test flood, according to Cook. Lake Powell’s level was high due to a couple of above average water years, but the dam’s power plant was capable of handling the volume of water.
The upper basin states have acknowledged the national importance of the Grand Canyon and the possibility that periodic floods could benefit the Canyon’s resources.
“We think the opportunity for doing these things with good management is fully there, and I think that’s the spirit in which we and the USBR got together to resolve what had been a two-year legal dispute,” Cook says.
“[But] it’s not going to be done at the expense of the water supplies and the economics, and that’s what the secretary agreed to before he got to run this experiment,” he says.
“We are not going to run the Colorado River system like a great environmental experiment, not if we can help it. There’s too much at stake.”
Despite Babbitt’s pronouncement of a new era, USBR and Interior Department officials are downplaying the test flow’s significance in the overall operation of federal dams. They say that beach-building releases will only be necessary every 5 to 10 years, and that they have not chosen any specific sites or dates f9& another release.
Also, since most sand relocation occurred during the first couple of days of the test flow from Glen Canyon Dam, researchers say future flows may be shorter than seven days.
“I don’t know if I’d go so far as to say we’re re-thinking the operation of dams,” Schaefer says. “Certainly, we’re looking at taking advantage of times whenwe have some water available to us. It’s more a matter of looking for opportunities to modify our policy on theedges to see what the benefits are.
“I think if you look at a flow of two to three days, once every 10 years, the water loss and power loss concerns are fairly minimal, and we can do things upfront to further minimize the economic impact,” he says.
Still, questions and concerns persist. And although currently, all may seem quiet on the western front since the Glen Canyon test flow, the battle is likely to continue as thirst for the Colorado’s water keeps growing.