What happens if we have another dry year on the Colorado River?

One of the big problems caused by the current breakdown in Colorado River diplomacy is the danger it poses if we have another bad year on the Colorado River.

A new Bureau of Reclamation analysis puts some numbers to the fear – a credible risk that Lake Mead could drop to elevation 1,062 by the end of 2019, just 20 short months away.

This nice chart put together by the Metropolitan Water District of Southern California, part of Met’s Water Supply Conditions Report (pdf), nicely illustrates what’s been going on in recent years:

Powell inflow, courtesy MWD

There’s a point my friend and book-writing partner Eric Kuhn has been making that shows up nicely in this graph. We’ve had four consecutive decent years. From 2014 to 2017, we have’t been in “drought” (whatever that word even means any more). That string of relatively good years (or at least “not bad years”?)  has enabled the 9 million acre foot per year releases that has so exercised the interbasin conflict between the Central Arizona Project and other basin water users. 9 million acre feet per year – well above the Law of the River-mandated 8.23 million acre foot release from Lake Powell – has bought time for negotiations over new management rules to reduce everyone’s demand on the system. But even with those big releases – the Upper Basin from 2014 to this year has delivered 2.3 million acre feet more than the Law of the River requires – Lake Mead has dropped 10 feet.

The bureau’s April “minimum probable water supply forecast” suggests a risk of a 1.2 million acre foot/13 foot drop in Lake Mead in 2019 if the winter of 2018-19 is another bad one. That “what do we do if it’s another bad year” question was lingering in the background of Monday’s meetings in Salt Lake City among and between Upper Basin water managers, the Bureau of Reclamation, and representatives of Arizona.

No one wants to be in the midst of trying to negotiate new rules while Lake Mead water is circling the drain. There are some incentives to laying down a workable framework, a “Drought Contingency Plan” or whatever, this year, before the frenzy.