Colorado River's health is vital to West
by Shaun McKinnon
Jan. 21, 2003 12:00 AM

The West's hardest-working river beat the drought - this time.

Robbed of its usual snowpack and reduced to barely one-quarter of its usual self, the Colorado River still filled all its deliveries for the 2002 water year, drawing heavily from a chain of enormous reservoirs built for just that purpose.

But the drought has refocused the debate about how hard one river can work and whether this one can meet a growing list of new demands that range from protecting endangered fish to restoring the Mexican Delta. Most experts agree that the Colorado is overcommitted, and at least one study now suggests that within 30 years, some of the river's users, starting with Arizona, may start to come up short.

"The future of the Colorado River will be shaped by drought and population growth," said Interior Secretary Gale Norton, who this month forced California to stop taking water beyond its legal allocation. "No longer will we have excess water or full reservoirs. The era of limits is upon us."

Drought is nothing new on the Colorado River. Studies at the University of Arizona Tree Ring Lab show evidence of dry periods much longer and deeper than this one. One megadrought during the early 1500s reduced the river to little more than a trickle.

Still, in the river's brief recorded history, which dates back a little more than 100 years, the 2002 water year now ranks as the driest. The total flow from Oct. 1, 2001, through Sept. 30, 2002, was slightly more than 3 million acre-feet, one-fifth its long-term average.

"We always think we can get by longer in years of above-average rainfall, but we don't count on the drought years," said Philip Fradkin, author of A River No More, a study of how the Colorado River was developed. "The West is a land of incredible growth, and growth is on an upward curve right now. When the growth curve intersects the drought curve, someone's going to be hurting. That was not a question that was conceived of when the original (Colorado River) compact was drawn up in 1922."

The West has survived, Fradkin and others say, because it has plumbed the Colorado to within its last drop of water, regulating its flows to meet the needs of 25 million people.
"If we didn't have those reservoirs, we'd be in big trouble," said Robert Johnson, director of the Bureau of Reclamation Lower Basin Region. "In a drought condition like this, not having that storage could be a disaster in terms of being able to meet water deliveries and the economic needs of the Southwest. The history of the Colorado River basin is dry cycles and wet cycles. This system allows us to manage it very well."

Simulated drought
So well, in fact, that scientists were unable to simulate a drought on the Colorado severe enough to drain every reservoir.

The U.S. Geological Survey devised a computer model in 1995 using some of the driest years from the late 1500s and from a severe drought in the 1950s. Researchers developed a worst-case drought and applied it to the river as it is managed today, figuring in available storage and existing annual demands.

Then, to make things interesting, the research team gave the drought a nastier edge than nature ever has, adding one dry year after another without the occasional spike in rainfall that usually shows up over such a 20-year period.
In the end, according to hydrologist Benjamin Harding, one of the study's authors, even "the fiendish, progressively deepening 19-year drought" used in the simulation failed to drain all the Colorado's reservoirs, though severe water shortages would likely occur during three to eight of the years.

But actual water supplies were only part of the story, according to Harding. A prolonged regional drought would result in billions of dollars in economic loss to the seven states that rely on the river. The dams on the lower Colorado would be unable to generate electricity for several years at a time, leaving Phoenix and Los Angeles to scramble for alternate sources of power.

The study estimated actual losses at about $2 billion a year, but that doesn't include the domino effects that would rip through the economies of Arizona and California.
Such a drought also would inflict disastrous damage to the environment, the study found. Endangered species could become extinct and riparian areas could vanish.

Dangers clear
Environmental activists say studies like that one illustrate the dangers of overcommitting the Colorado. The river barely sustains itself during normal precipitation years and could collapse in a long-term drought.
"When water becomes scarce, the environment loses out," said Pamela Hyde, executive director of the conservation group Southwest Rivers. "What I'm seeing this year is people telling us they'd like to help but the water for environmental needs is voluntary and the water rights are not. It's more subtle than that, but it makes it difficult for places like the Grand Canyon or the (Colorado River) delta."

Most river watchers, even those on opposite ideological sides from the environmental groups, now agree the river probably can't deliver enough water every year to fully meet every demand. When the seven Western states sat down and divvied up the Colorado in 1922, it was running at what turned out to be historically high levels, about 18 million acre-feet a year.
As a result, the seven states allocated 15 million acre-feet just for their own use, then over time carved out shares for Indian tribes and for Mexico, which by itself has rights to 1.5 million acre-feet a year.

The average annual flow over the past 30 years has been about 12.2 million acre-feet.
One of the reasons the states are able to make do with lower flows is that the upper-basin states of Utah, Wyoming, Colorado and New Mexico have never used their full allocations. That water runs down river to meet the greater demands of the lower-basin states, Arizona, Nevada and California, as well as Mexico.
But the upper-basin states are now looking at ways to capture some of their unused shares. Colorado officials are studying new storage options, perhaps patterned after Arizona's water bank, which was established in 1996 to allow this state to use its full allotment.

2030 seen as critical year
Some projections now suggest that by 2030, the river will start running short, said Larry Dozier, deputy general manager of the Central Arizona Project. A combination of increased demands and potentially drier climatic conditions will leave the seven states with less water.

That's a critical point for Phoenix and Tucson because their share of the Colorado, the 1.5 million acre-feet that flows through the CAP canal, carries the lowest priority. That means in a shortage, California, Nevada and western Arizona would take all their water before the CAP got a drop.

How seriously such a scenario would affect the Valley is unclear. Dozier said that by that time, the state will have stored enough water through its banking program to carry municipal customers through some shortages. The bank already holds about 1.5 million acre-feet, enough to cover at least three years of potential shortfalls.

The CAP system also has a built-in buffer: the water now used by agricultural customers. That water is not guaranteed in any given year, and in a shortage situation, it would be transferred to cities and towns.

Line of defense
Rita Pearson Maguire, former director of the state Department of Water Resources, said she thinks it's unlikely Arizona would face severe shortages even if the river runs low. The state's water bank would provide a first line of defense, and stepped-up conservation programs could buy additional time.

"That doesn't mean we should be complacent," said Maguire, now president of the Arizona Center for Public Policy. "The consequences of that situation would be dire. No one wants to see it happen."

Other factors also will affect how the Colorado survives a sustained drought:

• Climate changes, even if they're short-lived, can affect the river's flow. Just in the past century, the Colorado's average volume has fluctuated by more than 6 million acre-feet, twice what Arizona uses in a year. If the region is shifting into a drier pattern, as many climatologists believe, the river won't get the runoff it needs to satisfy all the demands.
A 1993 study by the Pacific Institute for Studies in Development, Environment and Security examined climate changes along the Colorado, using actual records, as well as evidence from tree rings and other sources.

"The slightest change in climate one way or another produced huge differences," said Peter Gleick, the institute's president and co-founder. "When it was dry, there was much less water, and when it turned wet, there were big floods."

• California for years has taken far more than its share of river water, soaking up anything the other states failed to use. Even after the other states complained, California negotiated an agreement that gave its major water providers 15 years to reduce their consumption, forcing the government to declare artificial surpluses and further drain the reservoirs.

Plan unravels
That interim plan unraveled at the end of 2002 when one of the key players, an agricultural district east of San Diego, refused to accept the agreement. As a result, the Interior Department cut off California's access to extra water.

But the 15-year plan could be revived, and some Arizona officials worry about the effects of what amounts to a "legal fiction" that the river is running a surplus.

"That may not last forever," said Terry Goddard, a member of the CAP's board and the state's attorney general. "If we don't get some rain soon, we're going to be in a critical situation. Arizona has the last straw in the river, so we are the most vulnerable."

• Environmental groups want more and more of the river set aside to protect endangered species and wildlife habitats. They are fighting to divert water to California's Salton Sea, a critical migratory bird habitats, and won a fight to change the way Glen Canyon Dam operates as part of a plan to protect the Grand Canyon.
Potentially more troublesome for the seven river states are efforts to restore water to the Colorado River Delta in Mexico. Once a lush, riparian jungle teeming with diverse plants and wildlife, the delta is now a desolate, salty desert, the river itself choked dry before it reaches the Sea of Cortez.

Delta restoration supporters have appealed to U.S. and Mexican officials. Mexico has raised claims about the quality and quantity of water it receives under its treaty with the United States and could try to make the delta an issue as well.

River advocates insist they're not asking the seven states to give up much: "As little as 1 percent of the river's flow might be enough to preserve key habitats," said Ed Glenn, a University of Arizona environmental science professor.

But 1 percent of a river with nothing to spare won't come easily, especially if the region is shifting into a drier climatic cycle.
"The wild cards here are the environmental claims on the system," Maguire said. "It throws a real monkey wrench into what's available. Hopefully, the courts will continue to understand that we need to meet municipal and agricultural demands first."

Chance to reallocate
Conservation groups say protecting the river's health is as critical for traditional water use as it is for natural resource management. If the river can't sustain itself, everyone loses. Some groups believe the drought offers a good opportunity to reallocate the river, taking into account its lower flows.

"People say they know the environment is a user," said Hyde of Southwest Rivers. "Wouldn't it make more sense that we actually put aside some water for the river itself? No one likes this drought, but this is one door that might open in a crisis situation."

Fradkin, the author, said he's doubtful the seven river states would ever agree to reopen the agreement that divides the Colorado, even though he believes the compact is now flawed.
"I'm not sure what would make them move, other than a drought of longer duration and greater intensity," he said.

"It really takes suffering and extreme circumstances, extreme drought conditions over a prolonged period of time. It has certainly occurred in the past and will certainly occur in the future."