Bureau of Reclamation and the Colorado River: Evaporation History, SEIS, and the Short-Term Conservation Plan

The Bureau of Reclamation (Reclamation) recently released a comprehensive report titled "Mainstream Evaporation and Riparian Evapotranspiration," shedding light on historical natural losses along the lower Colorado River. This study delves into water surface evaporation, soil moisture evaporation, and plant transpiration, providing crucial data for managing regional water operations and enhancing modeling efforts.

The report highlights that approximately 1.3 million acre-feet of losses occur annually along the lower Colorado River mainstream, with significant portions attributed to evaporation from Lake Mead to the Mexican border and transpiration from natural vegetation.

In tackling the challenges posed by climate change and drought, Reclamation employs innovative strategies and collaborates with basin states, tribes, stakeholders, and the public.

President Biden's Investing in America agenda is providing historic funding and resources to enhance water conservation, improve system efficiency, and safeguard reservoir levels.

Recent projections indicate a reduced risk of critical reservoir elevations, providing optimism for water deliveries and power production in the region.

You can access the Mainstream Evaporation and Riparian Evapotranspiration report on the Reclamation website here.

This report along with the Colorado River SEIS are providing support for the short term conservation plan that was recently announced.

All of these efforts are contributing to the post-2026 operational agreement that must be solidified in the next year.

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Shaina Shay is an accomplished water professional with over a decade of experience in water policy, management, conservation, and community outreach. Her passion for pragmatic information sharing drives her work across the U.S. and Australia, where she has held roles with investor-owned utilities and as a senior water market specialist. Shaina's commitment to the field is reflected in her leadership positions within the American Water Works Association (AWWA), American Society of Civil Engineers (ASCE), and the Southern Arizona Water Users Association (SAWUA).