For more than a century of development, Colorado River governance has lived under a
tension between individual communities’ desires to use more water and the collective
need to balance basin-scale supply and use for the benefit of the region as a whole.
Incentives favoring individual communities at the expense of the collective good have
brought us to the edge of the current crisis.

– Considerations for Assigned Water after Expiration of the 2007 Guidelines, Kathryn Sorensen, Sarah Porter, Anne Castle, John Fleck, Eric Kuhn, Jack Schmidt, Katherine Tara

The latest project from our little Colorado River working group takes a deep dive into the arcane rules governing what Arizona State University’s Kathryn Sorensen has dubbed “assigned water” – water that results of conservation efforts, set aside in the Colorado River Basin’s reservoir storage accounts for the future use of whoever did the conserving. Sort of.

While most of of the attention right now is focused on the top line conflict among the basin states, there remains a need to get the down-in-the-weeds details right.

Originally developed as a tool called “Intentionally Created Surplus” in the 2007 Colorado River operating guidelines (who names these things?), Assigned Water has become a critical tool for managing water use reductions in a way that helps ensure reliability for the water users to whom the tool is available. It’s extremely valuable, but is not without its drawbacks – crowding out conservation efforts that might benefit the basin as a whole, inadvertently shifting system water that again might benefit the basin as a whole into an individual water agency’s savings account, and delaying shortage declarations that might have enforced deeper cuts, sooner.