April Reese, Land Letter Southwest correspondent
A new report by the U.S. Geological Survey suggests the drought parching the Colorado River Basin could be the worst in 500 years, prompting water watchdogs to warn of an impending water crisis in the region. But federal water managers say there is still plenty of the West's most precious natural resource to go around.
The USGS report -- "Climatic Fluctuations, Drought, and Flow in the Colorado River" -- summarizes the most recent data on drought and water supplies in the basin. It says the current dry spell reduced flows in the Colorado River to the lowest levels on record -- about 5.4 million acre-feet (maf) during 2001-2003.
Looking at five-year averages, 7.11 maf flowed down the Colorado between 1999 and 2003. The next-lowest five-year period occurred more than 400 years ago, from 1590-1594, according to tree ring data.
"These comparisons suggest that the current drought may be comparable to or more severe than the largest-known drought in 500 years," the report states.
USGS researchers also noted that the period used by federal water managers to divvy up the river's water under the Colorado River Compact -- 1905-1922 -- had some of the highest flows of the 20th century. The average flow for that period was 16.1 maf, more than the twice the level of recent flows.
Gregory McCabe, a Denver-based USGS scientist who co-authored the report, said a confluence of climatic forces from both coasts is responsible for the current drought.
While alternately cool and warm currents in the Pacific Ocean have long been known to influence conditions in the Interior West, researchers have found that East Coast weather dynamics also play a role. "When you have a warm North Atlantic, you have a good chance of drought," McCabe said.
Does the current system work?
If drought is the normal condition in the Colorado River Basin, water managers need to change their way of thinking, said Owen Lammers, executive director of Living Rivers, an advocacy group based in Moab, Utah.
"Whether it's five, 10 or 15 years [long], we're going to face this at some point, so we might as well put in place a system to deal with it," he said. "In order to do that, we have to address the demand question. So let's start doing it, instead of waiting until we're in a crisis."
Storing water underground, where less is lost to evaporation and sediment build-up, could be part of the solution, Lammers suggested. But since nature is cutting the supply, water managers and consumers have to cut demand, he added. Switching from water-intensive crops such as alfalfa, which is grown to feed cattle, to less thirsty food crops and adopting municipal conservation and efficiency measures could cut the region's consumption of Colorado River water in half -- enough to bring demand in balance with supply, Lammers said.
Under the Colorado River Compact, signed in Santa Fe, N.M., in November 1922, the river's water was divided equally between upper and lower basin states, with the line drawn at Lee's Ferry, located above the Grand Canyon in northern Arizona. Colorado, New Mexico, Utah and Wyoming fell above the line, while Arizona, California and Nevada fell below.
Each basin was to receive 7.5 maf per year. Allocations for individual states vary widely, from California's 4.4 maf to Nevada's 300,000 acre-feet (Land Letter, Feb. 5).
If the drought continues, which many scientists say is likely, Lake Powell and Lake Mead could run dry, Lammers warned.
"Right now we're seeing twice as much water being used in Lake Mead than is coming [into the reservoir] from Lake Powell," he said. "At that rate, we're going to see Lake Powell empty in two to three years, then Lake Mead not long after that. In 2006, there's going to be real, real problems. That's when we may not have enough water to meet all the allocations downstream."
But Bureau of Reclamation spokesman Barry Wirth pointed out that Lake Powell and other reservoirs in the Colorado River Basin are fulfilling their purpose as a water insurance policy and so far have passed the most severe drought test since the system was built.
Bennett Raley, assistant Interior secretary for water, said that even if the drought worsens, there will be enough water.
"We think the drought is serious but not a crisis, because under any foreseeable scenario, there's going to be water for the economic engines of the West to continue to grow and prosper," he said in a phone interview from Denver, where BuRec was meeting with USGS researchers to discuss the drought. "Even under severe drought, the West doesn't dry up and blow away."
Raley noted that about 5 maf of the 7.5 maf allocated to the lower basin states is used for agriculture. If the drought worsens, some of the water consumed by farms could be transferred to cities, he said. Some urban areas have already cut deals with farmers to secure more water (Land Letter, March 18).
The federal government has a limited role to play in preparing the region for an extended drought, he added. "I just am at a loss where in the Colorado River Compact it requires Soviet-style planning," Raley said.
The federal government will step in to help resolve disputes between states, as it did when tensions over water use flared between Arizona and California, Raley said. "The federal government has said pretty strongly that if the states don't come up with a solution, it will fill the vacuum."
But so far, the states have been proactive in working together to find solutions to water challenges, he added. The upper basin states met in Salt Lake City recently, and drought was a priority topic of discussion at a meeting of the Western Governors' Association in Santa Fe this week.
