From email from the Community Agriculture Alliance (Sally Cariiveau):
November 5, 2024
The Colorado River Basin is in the midst of a 23-year drought. Reduced precipitation, mostly in the form of snow in the western mountains, has caused water administrators at the federal, state and local level to seek ways to cut back usage. But many of us in the high country do not need water managers to tell us to reduce usage. Mother nature kindly, or unkindly, does that for us.
With limited storage at higher elevations, snowpack is the source for virtually all water on the West Slope. As the Basin experiences a steady decline in precipitation, West Slope water users, especially irrigators, find that in many years, they are subject to “natural curtailment.” Less snowpack means less water.
Snowpack is a shared resource in the Mountain West. The water from snowmelt that feeds the West Slope also feeds the Colorado River. The Colorado serves Lake Powell and then Lake Mead, and ultimately consumers in the Lower Basin (Arizona, California and Nevada).
With minor exceptions, all Colorado River water used in those Lower Basin states is stored in the Powell/Mead reservoir system, which insulates them from the near-term impact of reduced hydrology upriver from Powell. This system has led to a common belief that the Upper Basin states (Colorado, New Mexico, Utah and Wyoming) can mitigate drought-induced problems in the Lower Basin simply by sending more water downstream.
Unfortunately, data indicates that during times of hydrological shortfall, the Upper Basin is already naturally experiencing reductions. Recent history provides a high-level example. In the five years from 2016 to 2020, usage averaged 4.6 million acre-feet in the Upper Basin. In 2021, a low-precipitation year, that figure fell to 3.5 MAF, clearly demonstrating the natural curtailment effect.
During the 2016 to 2020 period, Lower Basin usage averaged 10.7 MAF, an amount which actually climbed to over 11.0 MAF in 2021. As a benchmark, the 1922 Colorado River Compact optimistically allocates 7.5 MAF to each basin.
In dry years, natural curtailment impacts nearly everyone on the West Slope. Ranchers on tributary creeks often have to choose which headgates and ditches to operate. Even irrigators on the mainstem of the Elk and Yampa have years when, in late summer, they are required to use far less than their adjudicated rights.
Fishing, rafting/tubing and other recreational uses on the Yampa are often restricted, while water districts experience cutbacks during late-season low flows.
Meanwhile, solutions to Colorado River shortages have been elusive, and discussions difficult to facilitate. Politics and public messaging have played a major role; Lower Basin organizations have used every major media outlet to build public sympathy for their argument that they should not be the only ones to “sacrifice.”
Natural curtailment in the Upper Basin has been, until very recently, far outside of public perception. But it exists, and water users and organizations of the Lower Basin must acknowledge and understand it as a key component of future operating agreements.
We in the Upper Basin need to make natural curtailment a part of our story. Raising public awareness of this elemental fact can help us to defend our rights in the Colorado River.
