The booming Rocky Mountain snowpack has eliminated the risk of a formal Lake Mead “shortage” declaration in 2020, and has substantially reduced the risk in 2021, according to the latest Bureau of Reclamation 24-month study. More importantly, in my view, is the reduction of a longer term risk of a legal battle over the Upper Basin’s Mexican Treaty delivery obligation.
The current forecast calls for Mead ending 2019 at elevation 1,080, five feet above the threshold at which a set of rules previously developed by state and federal governments would have reduced allocations to Arizona, Nevada, and Mexico. That is more than eight feet higher than the projected elevation just a month ago.
More importantly, the new projections suggest now that there will be another 9 million acre foot release from Lake Powell in 2020, rather than the 7.48maf 2020 release projected just a month ago. The result is a preliminary end-of-2021 Mead forecast 20 feet higher than was expected just a month ago:
It’s that shift from a 7.48maf release next year to a projected 9maf release, the result of operating rules in the 2007 Interim Guidelines governing balancing the contents of Mead and Powell, that’s the huge deal here. It means the water users in the Lower Colorado River Basin will continue to get extra water, above and beyond their legally expected 8.23maf releases each year. If this forecast holds, it would mean that since 2011, the Upper Basin would have delivered an excess of at least 9.4 million acre feet, above and beyond the legal requirements of the Colorado River Compact.
A series of 7.48maf releases from Powell – possible under the current operating rules if we were to have really bad Upper Basin hydrology – would have put us into dangerous legal territory, in terms of how the rules governing water delivery obligations under the Mexican treaty are interpreted. One of the basin’s unresolved legal questions is the extent of the Upper Basin’s obligations to deliver half of the water needed to meet the U.S. obligation to deliver 1.5maf per year to Mexico. A series of 7.48maf release years could have forced a legal test of that question, which is one of my “how the legal system could crash” fears.
This year’s snowpack seems to have significantly reduced that risk for the foreseeable future.