The Colorado Division of Water Resources and the New Mexico Office of the State Engineer have identified and set as a priority the need to update their extreme precipitation estimates for use in the evaluation of spillway adequacy for dams in these states, based on the most modern methods and scientific understanding available. Due to similarities in geography and meteorology between Colorado and New Mexico, a cooperative, regional study (Colorado-New Mexico Regional Extreme Precipitation Study; CO-NM REPS) has been undertaken, the first instance of states combining resources and working collaboratively toward a solution to the problem. The project began in June 2016 and is scheduled to be completed in June 2018. Of particular concern in both states are questions about the physical limits on high-elevation rainfall amounts and the annual exceedance probability (AEP) of the extreme rainfall amounts used for spillway design. This has led to an innovative ensemble approach deploying three different methods to update extreme precipitation estimates. The CO-NM REPS does not seek to explicitly incorporate climate change influences in Probable Maximum Precipitation (PMP) estimates through any three approaches. Recognizing that the approaches may have limitations in characterizing future risk in a changing climate, the study’s sponsors have asked WWA to take stock of the state of the science and practice in PMP estimation and climate change in a white paper that will become an appendix of the study final report. An initial literature search and review was completed in spring 2017, and is currently being supplemented by a survey of the experts comprising the CO-NM REPS Technical Advisory Board.

This project earned a CO-Labs Governor's Award for High-Impact Research in 2019! Learn more here: https://www.2019govawards.com/the-winners