BOULDER CITY, Nev.—Lake Mead, the largest reservoir in the nation, is shrinking drastically—with consequences that could ripple across the West.
More than a decade into a drought that has plagued the Southwest, federal officials for the first time plan a sharp cut in the amount of Colorado River water that flows 360 miles from Lake Powell into Lake Mead. In the year starting Oct. 1, officials at the U.S. Bureau of Reclamation said Friday, that supply will drop by nearly 10%—roughly equivalent to the annual water usage of about 700,000 families.
The cut will translate into a reduction in hydroelectric power generation in some areas served by the reservoir—Nevada, Arizona and California—and brings the reservoir level close to a federal declaration of a water shortage. Such a declaration would mean that Nevada and Arizona would face having their water allocations cut.
“This drought continues and we can’t really tell when it’s going to end,” said Terry Fulp, director of the bureau’s lower Colorado region. “It points out we have to be cautious with all of our water use.”
The cutback is being ordered as part of a 2007 state-federal agreement designed, in part, to keep the levels of the two reservoirs balanced so they can be operated in tandem, maintaining more storage overall. It will be the first reduction since completion in 1963 of the Glen Canyon Dam that formed Lake Powell, which straddles Utah and Arizona.
The effect on Lake Mead will be a drop in water level of eight feet, which will come on top of receding water levels that already have totaled about 100 feet since the drought took hold in 2000.
Water levels at Lake Mead now stand at an elevation of 1105 feet.
The new cutback will bring the level perilously close to a federal trigger point of 1075 feet—the measure at which the Interior Department would declare a water shortage.
Mr. Fulp said in an interview that there is a 50% chance such a shortage would be declared in 2016; a probability he added has been increased this year as the drought has intensified.
The reduction will result in an 8% decrease in electricity production at Glen Canyon Dam, requiring a federal power agency to spend about $10 million to buy electricity on the open market to meet customer demands, said Lisa Iams, a Bureau of Reclamation spokeswoman in Salt Lake City.
While other impacts in the short term are expected to be limited largely to tourism and recreation on Lake Mead, water managers across the Southwest said more serious disruptions could result by 2016—potentially putting a crimp in region’s economy.
Lake Powell is used by the upper basin states as a place to store water that they contractually have to send downstream to the lower basin states. States like Colorado and Wyoming get to take water out of the Colorado as it flows past, so long as they save some for the lower basin.
Longer term, the Southwest faces the challenge of managing a river system that is already heavily taxed. A Bureau of Reclamation study last year found the river system wouldn’t be able to meet demand in 50 years, due to climate change and the region’s forecast growth. Water managers say they will have to come up with new ways to stretch supplies of the river and other sources, such as through use of new technology to increase efficiency.
“This is a long term issue for us,” said Jeffrey Kightlinger, general manager of the Metropolitan Water District of Southern California, which provides water from the Colorado to 19 million people.
One of the more pressing issues faces the Southern Nevada Water Authority, which depends on two intake points in Lake Mead to pump all its water from the lake to customers. The highest intake could be unusable if the water falls below 1065 feet, leaving only one that sits at 1000 feet, said Patricia Mulroy, general manager of the authority. The agency is racing to complete a tunnel to create a third intake at a much lower depth,but Ms. Mulroy said the late-2014 expected completion of that $815 million project is too close for comfort, considering when the other intake may go out of commission.
“We thought we had five years [until the intake is exposed], but now we may have 24 months,” Ms. Mulroy said.
On top of that, Nevada, along with Arizona face having their water allocations cut if a shortage is declared. California wouldn’t see a reduction because it has higher water rights than the others in the lower basin of the Colorado. Upper basin states include Colorado, Utah, Wyoming and New Mexico, and some of their water is sent to Lake Powell.
In Nevada, Ms. Mulroy said her agency already has curbed water use enough through conservation measures, such as paying homeowners to replace turf lawns with desert landscaping, that further cutbacks probably wouldn’t be needed. Still, some businesses worry the ongoing water problems could eventually dry up the local economy.
“Water is life and this is the desert,” said Ron Nelsen, general manager of Pioneer Overhead Door, a Las Vegas maker of garage doors.
In Arizona, a reduction of 320,000 acre-feet, or one fifth its supply, would prompt the Central Arizona Project to cut supplies for farming and other lower-priority uses such as banking water underground to guard against a future emergency, said Chuck Cullom, Colorado River programs manager for the big water agency.
“When we do this, we reduce our future flexibility for droughts way down the road,” Mr. Cullom said. Mexican water officials weren’t immediately available for comment.
Tourism and recreation businesses at the Lake Mead National Recreation Area, meanwhile, stand to take a hit. Already, water levels have fallen so far a boat launch at Las Vegas Bay empties into open desert. While the National Park Service has extended boat launches elsewhere on the lake, visitors still complain of issues including having to navigate in dangerously shallow waters. John Harrington Jr. said he and his father went from 60 feet to two feet in just moments as they cruised in an 18-foot motorboat this past week. “It’s scary out there,” said Mr. Harrington, 47 years old, a real-estate broker from Henderson, Nev.
Forever Resorts, a concessionaire, operates only 35 of the 65 houseboat rentals it did at one bay in 2000, and has had to relocate two marinas because of the dropping levels, said Rod Taylor, regional vice president of the Scottsdale, Ariz.-based firm. The company has had to reduce its number of yearly employees, full and part-time, from 275 when the drought started to 150, in part because of the declining levels and also the recession, Mr. Taylor said. He expects business to suffer again after this cutback. ”We’re all waiting with baited breath,” he said, “doing our rain dances.”