For the latest “Ask me a Colorado River question,” a friend of Inkstain wonders:

Q: Can you move water from one Colorado River Basin state to another?

A: No.

OK, this is the Law of the River, so of course it’s more complicated than that, with numerous edge case exceptions, but basically, no, you can’t move water from one Colorado River Basin state to another.

The 1922 Colorado River Compact divided what the framers thought was a reasonable estimate of the Colorado River’s flow in half. States of the “Upper Basin” – Wyoming, Colorado, Utah and New Mexico – get 7.5 million acre feet per year, and state of the Lower Basin get 7.5 million acre feet per year.

The Upper Basin states subsequently got together to split up their share on a percentage basis:

• Colorado 51.75%
• Utah 23%
• Wyoming 14%
• New Mexico 11.25%

The Lower Basin states fussed and feuded and finally the Supreme Court stepped in and said:

• California 4.4 million acre feet
• Arizona 2.8 million acre feet
• Nevada 300 thousand acre feet

Each state then is left to its own devices to divide up its own share internally, based on its own internal water laws and politics. But one of those devices cannot be to buy some extra water from one of the other states.

The result is that, to the extent that we’re seeing innovative water sharing and transfer agreements, they all tend to happen within a single state.

In Arizona, for example, the Wellton-Mowhawk and Yuma Mesa irrigation districts are involved in deals that involve water conservation and transfer to urban water users. In California, the Palo Verde Irrigation District has a program in which land can be fallowed and saved water shipped off to Los Angeles. The Imperial Irrigation District has an agreement in which agricultural water conservation measures generate water that is then used by urban users in San Diego.

I say they all tend to happen within a single state, though, because there are interesting edge cases where boundaries are being tested. Nevada and Arizona, for example, have a program in which surplus Nevada water is banked in Arizona aquifers for later use. Complicated accounting swaps ensue through which, on paper, no water crosses state lines. Wink wink.

New Mexico is currently considering developing a New Mexico unit of the Central Arizona Project which would involved diverting Gila River water within New Mexico, before it gets to Arizona, and then (again on paper) swapping that water with downstream CAP water.

But the most interesting test of these boundaries is an effort currently under development that Henry Brean wrote about in May under which urban agencies across the basin would pool their resources to fund conservation programs (most likely ag conservation) somewhere in the basin. The saved water would simply stay in the river for everyone’s shared use – “system water”. The result is that water conserved in State A might then be used in State B, but no one’s accounting for it specifically. It’s a clever workaround.

So the answer to the original question is really, “Not exactly, but people are trying.”

Background:

• Overall Law of the River from the U.S. Bureau of Reclamation
• The Arizona-Nevada water banking program
• System conservation program