Deal outlines how states will share drought burden

Secretary of Interior Dirk Kempthorne will be in Las Vegas next week to sign a sweeping, interstate agreement that could blunt the impact of drought on the Colorado River and secure more water for Southern Nevada.

The agreement lays out new rules for sharing shortages on the river and jointly operating the twin reservoirs of Lake Mead and Lake Powell during extended dry spells such as the one that has gripped the region since 2001.

It also allows the Southern Nevada Water Authority to tap its groundwater holdings in Coyote Spring basin and its rights to water from the Virgin and Muddy rivers. More importantly, the authority would be allowed to take that water, which eventually could total almost 40,000 acre-feet, out of Lake Mead using its existing intakes at Saddle Island.

"It's hugely important for Nevada," said water authority General Manager Pat Mulroy. "It gives us enough of a bridge to build our instate project."

By 2015, the authority hopes to build a pipeline network to tap groundwater in rural basins across eastern Nevada. At a cost of as much as $3.5 billion, the project is expected to yield a maximum of 200,000 acre-feet of water a year for a growing Las Vegas that depends on the Colorado River for nearly 90 percent of its water supply.

There are about 326,000 gallons in an acre-foot, which is roughly the amount used by two Las Vegas homes in one year.

Kempthorne is scheduled to sign a record of decision formalizing the shortage agreement Dec. 13, when he will address the annual conference of the Colorado River Water Users Association at Caesars Palace.

The pact has been in the works since 2005 and follows several other major accords that have helped to ease a once-hostile relationship among the seven western states that share the river.

The Quantification Settlement Agreement in 2003 got California to stop taking more than its share from the Colorado. The Interim Surplus Guidelines in 2001 spelled out how extra water would be divvied up during wet years on the river.

"There have been a number of important agreements for managing the river in the last eight or nine years," said Bob Walsh, spokesman for the U.S. Bureau of Reclamation's office in Boulder City. "This is another big one."

It could be especially big for Nevada once the drought ends and the Colorado River returns to normal, Mulroy said.

That's when the water authority would be allowed to start using a one-time reserve of at least 400,000 acre-feet of water it would get in exchange for building a new reservoir in California that could cost as much as $206 million.

The 8,000 acre-foot reservoir would capture water that now flows across the border into Mexico but does not count against that country's annual share of the Colorado River.

Walsh said a few thousand acre-feet of water flowed across the border into Mexico just last weekend, when showers swept California's Imperial and Coachella valleys. The rain prompted farmers to cancel their orders for Colorado River water that was already on its way downstream from Lake Mead.

"It might happen three or four times a year. It might happen once a year," he said. "It's not something you can schedule because you can't schedule these storms."

Mulroy said the broad pact Kempthorne is slated to sign next week is made up of about two dozen smaller agreements among the seven Colorado River states.

The water authority board and Nevada's Colorado River Commission will hold a special joint meeting this morning to approve several elements of that total package.

At the heart of the overall agreement are rules designed to protect minimum water levels in lakes Mead and Powell through the year 2026.

Since 2001, the water level at Lake Mead has dropped more than 100 feet. A decline of another 35 feet to a lake elevation of 1,075 feet above sea level would trigger a federal shortage declaration and force Nevada, Arizona and Mexico to reduce their combined water use by 400,000 acre-feet a year.

The combined shortage would grow to 500,000 acre-feet at a lake elevation of 1,050, and to 600,000 acre-feet at a lake elevation of 1,025.

Nevada's share of those shortages would start at 13,000 acre-feet and increase to 17,000 acre-feet and then 20,000 acre-feet as Lake Mead continues to drop.

Mulroy said arriving at those figures was no simple task.

"It's never easy when seven states talk about how to share shortages and spread the pain," she said. "It's been a wild ride.

"Now we all know what to expect."

Contact reporter Henry Brean at hbrean@reviewjournal.com or (702) 383-0350.