Document Type

Report

Publisher

Utah State University

Publication Date

6-8-2026

First Page

1

Last Page

6

Abstract

There is consensus across Reclamation’s hydrologic ensembles that volatile Colorado River flow will continue, including annual drops of 6 million acre-feet of natural flow above Lake Powell. This volatility poses risk that water managers cannot respond fast enough with the consequence that Lake Powell and Lake Mead drawdown so they no longer fulfill their Congressionally legislated purposes: deliver water, generate hydropower, protect native fish, or sustain infrastructure. In this post we suggest four reservoir operational strategies to reduce all those risks: (1) Identify Catastrophic Elevations where we lose the ability to operate reservoirs for one or more legislated purposes, (2) Communicate Minimum Drawdown Elevations as storage buffers to mitigate catastrophic risks, (3) Release less than reservoir inflow and evaporation, such as 95% of inflow, and continue those releases to intentionally build storage above minimum drawdown elevations, (4) Increase the frequency of release decisions, such as to monthly, weekly or daily, to respond sooner to volatile flow. Water held in Lake Powell and Lake Mead between their minimum drawdown and catastrophic elevations generates continuing benefits for hydropower, native fish, infrastructure, and capacity to deliver water, whereas if released, buffer water can only be consumed once by downstream users. Larger buffer volumes further reduce risks. More frequent release decisions also give earlier, smaller, and smoother adjustments. Communicating operations that avoid catastrophe also allow users to better plan how to mitigate their own risks. We do not suggest minimum drawdown elevations or decision frequencies. Rather, we see need to communicate reservoir operations that maintain public trust that the Colorado River system will not collapse.

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