More Water Coming In To And Out Of Lake Powell
More water is apparently on the way to Lake Powell, which means more water will be able to be released from that body of water. The Bureau of Reclamation has released the April 24 Month Study, and it includes an increase in the downstream flows from Lake Powell to Lake Mead of up to 9.5 million acre feet (MAF) for this water year.
Glen Canyon Dam's annual release for the 2023 was initially set at 7 MAF based on the August 2022 24-Month Study. The 2023 Water Year started October 1, 2022 and runs through September 30th, 2023. The increase to 9.5 MAF is 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 a press release Commissioner Camille Calimlim Touton said,
Despite this year’s welcomed snow, the Colorado River system remains at risk from the ongoing impacts of the climate crisis. We will continue to pursue a collaborative, consensus-based approach to conserve water, increase the efficiency of water use, and protect the system’s reservoirs from falling to critically low elevations that would threaten water deliveries and power production.
Reclamation utilized the Colorado Basin River Forecast Center’s April forecasts and other relevant factors such as Colorado River system storage and reservoir elevations to make balancing adjustments to Lake Powell operations. According to that forecast, inflow to Lake Powell is forecast at 11.3 MAF which is 177% of average and an increase of 3.3 MAF from March which was 125% of average. Reclamation’s April 24- Month Study projects Lake Powell’s elevation at 3,576.50 feet at the end of the water year. This is approximately 40 feet higher and 2.74 MAF of additional storage than projected in the August 2022 Most Probable 24-Month Study, which was used to set the annual operations for Lake Powell and Lake Mead.
The Bureau of Reclamation has already increased the monthly release volume for April from Glen Canyon Dam from 552,000 acre-feet to 910,000 acre-feet to be better positioned to release up to 9.5 MAF by the end of the water year.
Taking advantage of April's higher water release, the Bureau of Reclamation is concluding a 72 hour high flow experiment from Glen Canyon Dam. This experiment involves a release of water from Glen Canyon Dam that is much larger than normal for approximately 4 days (including ramp up and ramp down).
The experiment is designed to move accumulated sediment from the Paria River up onto beaches and sandbars in Marble Canyon and eastern Grand Canyon to restore the Colorado River corridor in eastern Grand Canyon National Park. Sandbars serve as camping beaches for recreationists, while also supplying sand needed to protect archaeological sites.
Currently, high sediment loads and favorable hydrology conditions are present to support this experiment. HFEs are implemented under the provisions of the Glen Canyon Dam Long-Term Experimental and Management Plan which was formalized with a Record of Decision signed by the Secretary of the Interior in December 2016. The LTEMP operations and experiments assist the DOI in complying with the stewardship responsibilities of the 1992 Grand Canyon Protection Act.
This HFE will not affect the total annual amount of water released from Lake Powell to Lake Mead. The high flow experiment is under way now, and will begin ramping down on Thursday, April 27th at 9:00am and will be concluded by 10:00pm that evening.