Drying Lake Mead worries water users in Colorado
Western Coloradans visiting Lake Powell aren’t likely to see Molina resident Carlyle Currier atop a water ski or at the helm of a houseboat.
“I’m not real big into water recreation, to be honest. I like to have my feet on solid ground,” he said.
Though not an avid Powell-goer, the 56-year-old spends a fair amount of thinking about the massive reservoir of the Southwest, and increasingly about its downstream relative, Lake Mead in Nevada.
Currier is a farmer and rancher whose livelihood, and that of his industry, is directly tied to water. He is involved with water issues within the state as a member of the Colorado Basin Roundtable and as its representative on the statewide Interbasin Compact Committee. When he hears that Lake Mead’s water level is at a historic low, he worries about the degree to which Powell may be relied on to stabilize Mead’s water supply.
That Lake Powell supply is water that Colorado and other states in the upper basin of that Colorado River scarcely can afford to let go, Currier said.
Currier and others involved in water policy in western Colorado see Lake Powell as a bank account for upper basin states, ensuring their ability to fulfill their water delivery obligation to lower basin states under the terms of the 1922 Colorado River Compact.
Lower basin states are using more Colorado River water than they are entitled to under the compact — a rate that has proven to be an unsustainable during a decade of drought and has drawn down Lake Mead.
“If we are required to allow too much water to meet the needs of the lower basin … and those that benefit from Lake Mead, well, that puts us in jeopardy of lowering Lake Powell too much and getting us in real trouble if we do have another severe drought like 2002,” Currier said.
1,082 and falling?
Just a few weeks ago, Mead’s water elevation dropped to 1,082 feet above sea level, its lowest point since it was filled in the 1930s.
“Quite frankly, in terms of operating the reservoir, it was just a historical fact, not much more than that. But it was still of great interest, I think, to folks,” said Terry Fulp, deputy regional director of the Bureau of Reclamation Lower Colorado Region.
Much of the interest stems from the fact that Lake Mead is only 39 percent full and just 7 feet above the level that would trigger the first action under shortage criteria established in 2007 by former Interior Secretary Dirk Kempthorne. That action would force water shortages in lower basin states. Nevada would take a hit, but Arizona would suffer the brunt of the shortage because its Central Arizona Project has junior Colorado River water rights to California’s, a price it paid for getting support from California for the project.
The 2007 criteria also provided for coordinated operation of Powell and Mead, which Fulp characterized as helping the two reservoirs share the pain of bad water years between basins and the gain of good years. Under that coordination, the Bureau of Reclamation is expected to release extra water from Lake Powell in order to prevent Lake Mead from dropping to its trigger elevation, at least next year. Fulp said there’s a chance of that elevation being reached in 2012.
Eric Kuhn, general manager of the Colorado River Water Conservation District, which is based in Glenwood Springs, expects Lake Mead to continue falling. The lower basin has been relying on extra water releases from Powell in years when Powell has gotten big upstream inflows. But most of those inflows have been below average the past 10 years.
Powell has stabilized at around 60 percent of full after falling to about 35 percent in middle of the past decade, but it’s not taking in the kind of extra water that the bureau could pass on to Lake Mead and keep Mead from dropping, Kuhn said.
He said Arizona has been banking water underground in preparation for the shortage that’s likely to come.
“I think people are going to be politically very concerned, but don’t look for anybody to not water their lawn in Phoenix because of the shortage,” he said.
The politics of the situation concerns upper basin states such as Colorado. Kuhn believes the shortage criteria won’t be enough to stop Mead’s drawdown, which could lead to an Interior Department decision that more water should be released from Powell.
Fulp agrees the criteria now in place don’t assure stabilization of Mead’s water levels. But he said the guidelines also provide for states to be able to consider additional measures.
“We believe absolutely that everyone will come back to the table and we’ll solve it. It won’t be an easy thing,” he said.
Currier is concerned about Powell being seen as one solution to Mead’s problems because of how it relates to the upper basin obligation to deliver a 10-year rolling average of 7.5 million acre-feet a year to the lower basin, and additional water to Mexico.
“If we fall behind in those delivery requirements, we will be in serious trouble in Colorado,” Currier said.
Even though Colorado doesn’t use all of the water it’s entitled to under the 1922 compact, it could one day face a call under the compact to help ensure the delivery obligation is met.
“That would have huge ramifications for any junior water rights in Colorado,” he said.
Colorado River water rights within the state that are junior to 1922 could be shut off. Currier has some such water rights associated with Vega Reservoir, although most of his rights are older.
But he’s concerned about them as well. A lot of municipal Colorado water rights are junior ones, whereas most earlier rights belong to agriculture, Currier said.
“If all the municipalities are shut off, those cities are going to want my water one way or the other,” he said.
He fears an attempt to go after pre-1922 water rights through a constitutional amendment or a court fight, or by simply offering such large amounts to buy them that ranchers will sell out.
“It would be very detrimental to agriculture as a whole in western Colorado,” Currier said.
There has never been a call under the 1922 compact, and Kuhn said Colorado is “a long ways” from facing such a threat. Still, he said the concern is valid. If the hydrology trends of recent decades continue, he believes the threat exists of Powell and Mead being drained.
The water allocations contained in the 1922 compact were based on river flows in the years just before then, which turned out to be above average. Tree ring analysis also is painting a drier picture of the basin’s runoff history in earlier centuries, and Kuhn believes climate change also could affect runoff. Higher temperatures increase water evaporation and consumption by plants. The latter affects how much water reaches rivers and how much is required to irrigate crops and lawns.
Kuhn said lower basin states have been taking steps to conserve water, but they need to do more rather than relying on Lake Powell water and for the Upper Basin to meet its compact obligation.
“We’re hoping that the action occurs sooner than later, that we start to get serious about cutting back water use in the lower basin long before there’s a crisis,” he said.
Brad Mattas, owner of Mattas Marine & RV in Grand Junction, said the possibility of Lake Powell’s water level falling again is a concern. But even during its low point several years ago, “it was still a big lake,” he said.
He said reservoirs are intended to be filled up and drawn from as necessary.
“We don’t want to give up any more water than we have to, but if they need to draw some water, there’s plenty of water,” he said.
Ensuring Lake Powell’s water supply holds up is important not just for water interests and recreationists, but for continued hydroelectric power for upper basin users. That power also funds endangered-fish-recovery efforts.
At Lake Mead, another trigger elevation set in 2007 is 1,050 feet, which corresponds to when experts think the current turbines at Hoover Dam won’t be able to operate efficiently. Fulp said there also is concern that trapped air could damage turbines and other machinery. Power contractors plan to test new turbines that they hope can address some of the concerns.
The 1,050-feet mark also is the height of the upper intake for the Southern Nevada Water Authority, which serves Las Vegas. Fulp said it also has a lower intake, but that might not be adequate to meet peak summer demand. The authority is building another intake that “literally is going to tap into the bottom of the reservoir,” but it probably won’t be done until between 2015 and 2017, Kuhn said.
Fulp notes that Lake Mead has gone through “the worst 11 years on record” drought-wise, and he voiced confidence that such a trend won’t continue. He’s hopeful Mead’s water supply will hold up at least until the 2007 shortage guidelines expire in 2026.
“The real question is what do you do after that, and with increasing demands throughout the system … and with the prospect of declining supplies as projected by climate models, the question is really about sustainability of the system,” he said.
He said addressing that question is the goal of a Bureau of Reclamation Colorado River supply and demand study that attempts to look 50 years into the future.