The Arizona Department of Water Resources has published a thoughtful and also delightfully testy response to Enduring Solutions on the Colorado River, the white paper Kathryn Sorensen et al. (I’m one of the et alias) published in August.

First a reminder of our core premise:

As we work to reduce water use on the post-2026 Colorado River, two paths lie open before us.

One is to incentivize conservation by giving water users the chance to bank saved water for later use. Known most commonly as Intentionally Created Surplus (ICS), and more broadly in a series of increasingly creative implementations as “Assigned Water,” this creates short term savings. But in the long run, the approach entitles the users to take the water back out of the bank.

The other involves permanent reductions – “System Water.” Water use is reduced for the benefit of the Colorado River as a whole.

Investment in Assigned Water, attractive to water managers because of the allure that they can get their water back, has crowded out investment in the more durable System Water reductions that will be needed to bring the Colorado River into balance.

ADWR agrees with a lot of what we said (yay!):

ADWR agrees wholeheartedly with the general premise that System Water is preferable to any category of Assigned Water. Increased volumes of System Water will improve outcomes for water users across the entire Basin, as well as the environment. ADWR also agrees with the need to divorce decisions regarding system operations from any Assigned Water stored in the system.

ADWR takes issue with a lot of what we said (also yay!), and also was kinda mean – “Baseless Accusations and Little Substance” (also yay! because we need to be having these frank discussions – I worry being too polite isn’t helping right now).

I’m delighted this discussion is underway in a public forum. Go read the whole thing.