Folks on the Colorado River upstream of Lake Mead are sounding a little nervous.
Dennis Webb had a very nice piece in the Grand Junction Sentinel over the weekend taking stock. Meet Colorado rancher Carlyle Currier:
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.
It’s not a far-fetched fear. Recall the folks I talked to at Lake Mead last month, who argued that the solution to their lake’s problems was to release more water from Lake Powell upstream. While the current legal structure makes that difficult beyond efforts to equalize the contents of the two reservoirs so that they can, in theory, share both surplus and shortage, it’s a common line of argument.
- Lake Powell: 15.2 million acre feet
- Lake Mead: 10.0 maf
“Lower basin states are using more Colorado River water than they are entitled to under the compact” Is that still true? Was that ever true? I know California was way over its 4.4 MAFY allocation, but I thought the state’s argument was that it was taking Arizona’s unused share.
John, Please consider posting a guest piece on Joe Romm’s Climate Progress about the critical nature of the draw down of the Colorado River (Lake Powell) and what that means for the entire Southwest.
John, Please consider posting a guest piece on Joe Romm’s Climate Progress about the critical nature of the draw down of the Colorado River (and Lake Mead) and what that means for the entire Southwest.
Thanks for a great question, which (as usual) cuts to the heart of things.
Reasonable people can disagree, but there’s an arguable case that the Lower Basin’s total use is in excess of its Compact entitlement. It’s true that the delivery to Compact users falls within the Lower Basin’s 7.5 maf, but that does not count evaporation and system losses. When you add that in, they’re consistently over.
I laid out the math here, based on data from Paul Miller at USBR (see his slide part way down in the post):
I’m not sure I would have worded it the same way Webb did, because his shorthand misses the nuance of what counts as “use”, but the bottom line is that throughout the drought, Mead has continued to receive its full allotment from the Upper Basin, yet has continued to drop, because the Lower Basin’s consumption (both “use” and system losses) is in excess of inflow. This is the heart of the long term problem, and Webb’s wording captures the way it is viewed from the Upper Basin.
Interesting to hear from the Upper Basin, especially since last I read about the issue, the Lower Basin was starting to think about making a call on the Upper Basin.
Down here, I guess the predominant paradigm is that Powell is just extra on-stream storage for Mead, to be delivered on demand, because overall under the Law of the River the Lower Basin has priority over the Upper.
Also interesting that evap losses weren’t specifically included or excluded in the calculation of when an Upper Basin call can be made. I know that the original agreement is almost 100 years old, but you’d think that the original drafters might have thought of the problem of allocating evap losses. (To be fair, they actually may be. I’d need to check. But LoR analysis is time consuming and hard.)
I’ve been doing a lot of reporting on this lately, and I’ve not heard anyone seriously suggest a lower basin call. Legally at this point the lower basin can’t, because throughout the drought, the Upper Basin has consistently been able to meet its obligation of delivering 8.23 maf (or more). The shortage sharing agreement, agreed to by all the states (upper and lower) establishes some formal mechanisms that look robust enough to prevent a call. That was one of its key reasons for being.
Under the Law of the River, the lower basin’s priority doesn’t seem to extend beyond the upper basin’s requirement to deliver 8.23 maf (7.5 maf plus our share of Mexico’s water):
“The States of the Upper Division will not cause the flow of the river at Lee Ferry to be depleted below an aggregate of 75,000,000 acre-feet for any period of ten consecutive years reckoned in continuing progressive series beginning with the first day of October next succeeding the ratification of this compact.”
If there’s a drought, it seems as though we need to keep delivering that much water no matter what (though I’ve heard Upper Basin lawyers argue some nuance suggesting some uncertainty even there). As long as we’re sending the legally required amount past Lee’s Ferry, y’all down there seem to be on your own in terms of making the best use of the water we send you.
But you’re right about LofR complications, and I’m not an expert here by any means. Just sharing what I’m hearing as I talk to people who are.
I assure you if a call is made there will be a trial balloon first, and you’ll want to cover your ears from the water lawyers in Colo and UT shrieking to their staff to clear their desks and call their families and tell them they won’t be home for 18 months, and buy sheets for their cots in their office, fer chrissake!!!!
Nonetheless, about the overage use, IIRC CA was told to shore up their water down south as their overage was going to be cut off, and that prompted the IID and San Diego to scramble for some of the SWP water, esp from Westlands and fix some canal leaks to find water. But I was moving out of state at the time and lost track of the details so I may not RC.
Not sure what I was thinking of when I wrote that comment. Isn’t there something about equalizing lake levels?
Indeed, the new operating rules agreed to as part of the shortage sharing agreement have equalization criteria that in general allow extra releases from Powell when it gets above specified levels to try to equalize storage contents in the two reservoirs.
Aha. Have the equalization criteria been met / getting close? And you wrote “allow”. I thought the releases were mandated once the Lower Basin made the demand.
(You’d think that Nevada would be begging to get more water into Mead. And if the water drops below the penstocks [is that the right word for the inlet to the turbines?], LA DWP might be less concerned about making enemies in Colorado.]
Good catch – “require” is the right word, not “allow”.
We could see equalization release above 8.23 maf this year. The most recent “24-month study”, the place where all this is hashed out month by month as the water year progresses, says odds favor a release of 9 maf because of the equalization rules.