The Colorado River Basin is immersed in what’s been called the “millennial drought,” a drought that began in the year 2000 and persists today. Scientists have recently declared this to be the driest period ever recorded in the last 1,200 years. Average flows at Lee Ferry for this era have been approximately 12.6 MAF (million-acre feet) – roughly 4 MAF less annually than would be needed to meet the full Colorado River Compact allotments of the seven basin states and to the Mexican Treaty obligation to Mexico.
Ongoing and recent droughts have significantly reduced storage levels in Lake Powell. If these droughts continue, the ability of Lake Powell to satisfy its compact-obligation and power-generation purposes would be threatened. Drought Contingency Plans (DCP) are being developed for both the Upper and Lower Basins. While those plans, if implemented, would reduce the risk of a compact deficit or critically low storage levels at Lake Powell, they do not completely eliminate the risk for the Upper Basin states. The Risk Study is meant to address the likelihood of Upper Basin states being unable to meet their non-depletion obligations under the 1922 Colorado River Compact.
A Three Phase Approach
Phases I and II relied heavily on data and modeling from Hydros Consulting, as well as significant stakeholder input from the four basin roundtables within the district.
Phase I – Full Report
Phase II Task 1 – Full Report
Phase II Task 2 – Full Report
The third phase of the Risk Study was completed in 2019, and the final report is available here.
The purpose of Phase III of the Risk Study is to build on Phases I and II and continue to answer Colorado River system risk questions asked by the West Slope roundtables in the context of Colorado’s Water Plan and the development of the IBCC Conceptual Framework. Most notably the Risk Study Phase III will continue to address the IBCC Conceptual Framework Summary Point No. 4 which states: An insurance policy that protects against involuntary curtailment is needed for existing uses and some reasonable increment of future development in the Colorado River system, but will not cover a new TMD.