According to a new study by the U.S. Bureau of reclamation, the Upper Colorado River Basin received a 7% denser snowpack this year, but officials are still predicting lower water levels at Lake Mead.
Lake Mead’s depth remains of vital importance to the Lower Colorado River Basin, as its measurements are used by the Bureau of Reclamation to determine how much Colorado River water will be allocated between the states of Arizona, Utah, Nevada and California each year.
Denser snowpacks in the Rocky Mountains can contribute heavily to the flow of the Colorado River, but the Bureau of Reclamation said in its report that inflow throughout April and July into Lake Powell is expected to be only about 78% of its annual average. The agency said Friday the predicted shortage is due to extremely dry conditions in the Lower Colorado River Basin in October and November.
The biannual study indicates that Lake Mead’s elevation is expected to maintain “Tier Zero” conditions by January, with an expected elevation of 1,084.69 feet. Under “Tier Zero” conditions, Arizona will be forced to reduce its allocation of Colorado River water by about 192,000 acre-feet – a decrease of about 7% from its standard allocation of 2.8 million acre-feet per year.
The bureau also predicts that Lake Mead’s elevation will fall further, reaching 1,084.39 feet by 2022.
According to the bureau’s report, “Tier Zero” restrictions are part of broader efforts being implemented to reduce the near-term risks of further reductions to Arizona’s Colorado River supplies. Although municipalities such as Phoenix and Tucson will not be affected by the restrictions, the Central Arizona Project will see reductions to its own supply of Colorado River water throughout Arizona.
The Bureau of Reclamation has already begun efforts to work with multiple state, county and tribal water agencies – including the Mohave Valley Irrigation and Drainage District – to further conserve water throughout Arizona.
“The programs being implemented in Arizona and across the Colorado River system have helped avoid a near-term crisis in the system,” the bureau’s report said. “However, we continue to face significant near and long term risks to Arizona’s Colorado River supplies. We have much more work to do to address our shared risks.”