Pat Mulroy: The only reason why the two reservoirs, Lake Mead and Lake Powell, aren’t empty is because the Upper Basin is not fully using its allocation

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I ran across this interesting Q&A with Patricia Mulroy — General Manager of the Southern Nevada Water Authority — from Stephanie Tavares in today’s Las Vegas Sun. Mulroy describes the outlook for this summer and Nevada’s challenges:

There has been a lot of talk about how small Nevada’s allotment from the Colorado River is. Can we go to the federal government and ask for more water?

Um, no. In 1922 the seven states of the Colorado (River Basin) entered into a compact that divided the water in the Colorado River between two basins. The Upper Basin is comprised of Colorado, Utah, New Mexico and Wyoming. The Lower Basin is California, Nevada and Arizona. Each of the basins received 7.5 million acre-feet. In the Lower Basin that water was then further divided among the three states, among Arizona, California and Nevada. California, because it had the largest agricultural production, got 4.4 million, Arizona got 2.8 million and we received the remainder, 300,000, because there was no agriculture in Southern Nevada and that was the driver on where the water was going to go. The United States then entered into a treaty in 1944 with Mexico in which it guaranteed 1.5 million acre-feet to Mexico — that’s an obligation on the river. What happened was that in 1922 when (the states) went through those negotiations, they used the 50 highest flow years ever recorded on the Colorado River to determine what the average flow was. That was a mistake. We have learned since that really is not the average flow and that what they thought was around 17 million or 18 million acre-feet is probably closer to 13 million or 14 million acre-feet. So in truth, the Colorado River is already overappropriated. There has been more water given away than the river itself has. The only reason why the two reservoirs, Lake Mead and Lake Powell, aren’t empty is because the Upper Basin is not fully using its allocation. So a compact is not something the federal government can unilaterally overturn. It would require the agreement and concurrence of the Legislatures in every one of the basin states. And the United States has entered into compacts with its states all over the country. So it would set a hideous precedence if it tried to unilaterally override it. The result of that is that there is not a Legislature in the West that would ever give up its allocation. It would feel that it was being severed from what it perceived to be its birthright.

I think, however, over the course of the past 20 years, we have been able to put agreements into place that have afforded Southern Nevada the opportunity to take advantage of a lot more Colorado River water than it had 20 years ago. We have entered into a banking arrangement with Arizona. We’re paying it $350 million and it is banking 1.2 million acre-feet of its unused entitlement in its ground water basins for our future use. We have a banking arrangement in California whereby water we don’t use in Nevada we can store in California and take when we need it. We’ve entered into an agreement with California and Arizona to pay for a reservoir structure on the All-American Canal and for payment of that we will receive a one-time block of water that we can take down as long as there are no shortages. So we have the opportunity. I mean, quite frankly, if we didn’t have the drought and climate change staring us in the face, we would not be pursuing the in-state water project.

We’ve also gotten the ability to take water from the Muddy and the Virgin (rivers) … at Saddle Island (in Lake Mead) and we’ve got significant waters on the Virgin and Muddy rivers.

So if we had a Colorado River that was as healthy today as it was in the ’90s, none of the controversy that we’re having to go through right now with the in-state project would even be an issue. We wouldn’t be pursuing it at all. But the reality is that if what the scientists now believe to be the case that this is not just an isolated drought, that this is symptomatic of continuing lesser flows in the Colorado River, then there is a point of crisis that we’re going to hit.

We have two intakes in Lake Mead right now. Lake Mead is full at sea-level elevation 1,204. Our upper intake that was built in 1971 sits at 1,050. The second that we put in the mid-1990s is at 1,000 and we’re currently in the process of putting in the third intake, which will go underneath Lake Mead and come back up at elevation 890. It’s a very difficult project and a very dangerous project to build.

We are currently sitting at sea-level elevation of about 1,107 at Lake Mead. The latest report from the Bureau (of Reclamation) says Lake Mead is going to go down again this year. The snow has been evaporating in the Upper Basin, it’s called sublimation. And so what we thought might possibly be at least a close to normal year has turned pretty dastardly. So we could be as close as elevation 1,090 before the year is out. That puts us 15 feet away from the first shortage declaration.

The agreement we signed with the (Interior) secretary in 2007 along with the other Lower Basin states, at elevation 1,075 the secretary declares the first shortage and Nevada gets cut back. At elevation 1,050 he declares the second shortage, and we get cut back more. At elevation 1,025 he declares the third shortage, and we get cut back even further. Well, at 1,025 in Lake Mead you have less water than what the annual demand is. If we get to an elevation less than 1,000 we have less than 500,000 acre-feet left in Lake Mead.

The possibility of that happening puts this community in a horrible position of risk. You cannot conserve 90 percent of your water supply, it is physically impossible. You won’t have enough fire pressure in the hydrants to put out a fire. For that reason, to protect the community, we started developing the in-state project, because you have to bring water in from a place that is geologically separate from the Colorado River. You can’t depend on the river anymore.

All the exchanges, whether it’s ocean desalting that we’re working on with Arizona and California, whether it’s the banks — if you physically can’t take it, if the lake is in that dire stress, none of those work anymore. So we have to be able to bring water in from outside the basin and the only place that Nevada has is to look at its unused, unappropriated ground water, which is what we’ve filed on.

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