On April 20, Bureau of Reclamation released its April 24-Month Study, which includes an increase to downstream flows from Lake Powell to Lake Mead of up to 9.5 maf this water year (October 1, 2022, through September 30, 2023).
Glen Canyon Dam’s annual release volume for water year 2023 was initially set at 7.0 maf, based on the August 2022 24-Month Study, and is now projected to increase to up to 9.5 maf because of high snowpack this winter and projected runoff in the Colorado River Basin this spring. The actual annual release volume from Glen Canyon Dam is adjusted each month throughout the water year and is determined based on the observed inflow to Lake Powell and the storage contents of Lake Powell and Lake Mead.
While this water year’s projections are above average, the Colorado River Basin is experiencing severe drought conditions and system reservoirs remain at historically low levels. In response to this historic drought, Reclamation recently released a draft Supplemental Environmental Impact Statement to potentially revise the current interim operating guidelines for the near-term operation of Glen Canyon and Hoover Dams.
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Colorado River System Projections Overview
24-Month Study Projections
2-Year Probabilistic Projections
5-Year Probabilistic Projections
General Modeling Information