A crisis brews on the Colorado

For the first time since the federal Bureau of Reclamation began its massive dam-building program on the Colorado River in 1933, the seven states that depend on the river for drinking and irrigation water are bracing for a shortage. As the Colorado River Basin enters the sixth year of the worst drought in a century, Lake Mead is now at 56 percent of capacity; Lake Powell is at 36 percent. Together, the two reservoirs represent the Colorado River Basin’s water bank account, and the balance is dropping.

The secretary of the Interior could declare an official "shortage" as early as 2007, cutting off states’ water in ascending order of priority, irrigation-ditch style. But amazingly, the Interior Department still has no formal criteria for declaring a shortage, or for dealing with one. The Bureau of Reclamation’s river-management models are based on recorded streamflows going back to 1906, rather than on paleoclimate data from the past several hundred years that show more severe droughts, and those models didn’t predict that the reservoirs would go this low this soon.

"People thought they had a whole lot more time to deal with the issue," says Patricia Mulroy, the general manager of the Southern Nevada Water Authority, which supplies water to Las Vegas.

In an effort to avoid the cuts that would come with an official shortage, on Dec. 17, Deputy Interior Secretary Steven Griles gave the seven Colorado River Basin states until April to develop their own alternative to manage the dwindling water supply.

It’s a hugely contentious mandate, but the states are motivated by a shared desire to avoid a fight in court, which would be expensive, time-consuming, and a crapshoot. And many water managers say that tightening down water diversions now could help stretch supplies in the Colorado River and turn the "sudden death" of an official shortage into a series of more manageable crises, at least for a couple more years.

To address the drought long-term, states may finally have to start thinking as a basin, rather than just looking out for themselves. The states’ effort will center on finding flexible ways to manage Lake Mead, which serves as a drought-year bank account for the Lower Basin states — California, Arizona and Nevada — and Lake Powell, which is essentially an account for the Upper Basin states — Colorado, Utah, Wyoming and New Mexico (HCN, 11/10/97: Drain Lake Powell? Democracy and science finally come West). If both accounts can be kept from bottoming out for as long as possible, all seven states may be able to avoid an official shortage.

But getting some states to look out for anyone but themselves will be tough. The Central Arizona Project (CAP), which supplies water to Phoenix and Tucson as well as to farmers, has the worst water rights on the river, so if a shortage is declared, it will take the first cut. To guard against such a calamity, Arizona has been drawing its full allocation from the Colorado and "banking" unused water underground as its own, in-state, drought-protection policy. "The only way we’re going to get through those shortages is to use what we’ve banked," says CAP deputy general manager Larry Dozier.

But that strategy has raised the hackles of the other basin states, which are asking why, six years into the drought, Arizona is still siphoning water from the Colorado into its drought bank, rather than pulling water out of that bank.

"That has the effect of driving down the (entire Colorado River) system," says Jim Lochhead, a Glenwood Springs, Colo.-based attorney who represents a coalition of Colorado cities and irrigation districts. Because Arizona’s strategy lowers Lake Mead, says Lochhead, it creates more pressure on the Upper Basin to release water from Lake Powell.

The secretary of the Interior currently requires Upper Basin states to release 8.23 million acre-feet annually downstream to Lake Mead. An agreement between the states to share shortages proportionally, at least temporarily, would help spread the pain. If Arizona reduced its diversions, that would take some of the pressure off Lake Mead, and the Upper Basin states could ask the Interior secretary to reduce the amount of water they’re required to send downstream.

The Upper Basin states are likely to propose reducing their "delivery obligation" to 7.5 million acre-feet. But that, too, raises huge questions, because the U.S. is required to deliver 1.5 million acre-feet a year to Mexico, half of which now comes out of the Upper Basin. Although any "extraordinary" drought shortages are supposed to be shared by the two countries, just what extraordinary drought is, or how to deal with it, is something else that has never been defined.

An April review of water conditions in the Colorado River Basin will provide a clearer picture of options for this year. In the meantime, negotiations are sure to be delicate.

"The alternative" to a state-driven compromise, says Mulroy, "is going to be 15 to 20 protracted years in court, and abrogating our responsibilities as water managers to a judge."

The author is HCN associate editor.

• Water
• Bureau of Reclamation