FILE - In this April 14, 2013 file photo, hikers make their way along the banks of the Colorado River near Willow Beach, Ariz. Storms brought deep snow during the 2016 season to the mountains that feed the Colorado River, but the dried-out landscape will soak up some before it can reach the river and flow into Lake Powell, the nation’s second-largest reservoir. The snowpack in the vast Upper Colorado River Basin peaked at about 94% of average this month. (AP Photo/Julie Jacobson, file)
The drought-ravaged western U.S. landscape will absorb a greater than normal amount of runoff that feeds the Colorado River, according to the U.S. Bureau of Reclamation. This means the huge levels of snowmelt that ultimately results in hydropower generation will likely be lower than average.
The snowpack in the vast Upper Colorado River Basin -- encompassing almost 110,000 square miles of mountains, valleys and tributaries from Wyoming to New Mexico -- hit its seasonal peak this month, federal data show. It reached about 94% of the long-term average.
The melted snow makes it into the river and eventually to Lake Powell in Utah, the second-largest reservoir in the nation. The reservoir provides flow for power generation at the 1,320-MW Glen Canyon hydroelectric facility.
The amount of water that will reach Lake Powell is expected to reach only 74% of average, according to Reclamation. The agency manages Lake Powell and hundreds of additional reservoirs.
Water users and managers closely monitor the Upper Basin, especially in April, when the snow usually reaches its deepest levels and begins to melt into the Colorado River or its tributaries.
A dry fall and early winter reduced soil moisture in the basin, said Reclamation personnel Malcolm Wilson.
"When you have dry soil, the first place the water goes is to recharge that soil," he said.
Lake Powell is about 45% full amid a long-term drought, and Wilson said the lake was expected to rise 16 ft from this spring's snowmelt.
Releases from Glen Canyon Dam can fluctuate beyond those scheduled when it is called upon to respond to power outages or power system emergencies. Depending on the severity of the system emergency, according to Reclamation information, the response from Glen Canyon Dam can be significant, within the full range of the operating capacity of the power plant for as long as necessary to maintain balance in the transmission system.
Glen Canyon Dam typically maintains 27 MW of generation capacity in reserve in order to respond to a system emergency even when generation rates are already high.
System emergencies occur fairly infrequently and typically require small responses from Glen Canyon Dam. However, these responses can have a noticeable impact on the river downstream.
Based on the current forecast, the April 24-Month Study projects Lake Powell elevation will end water year 2016 near 3,600 ft, which is about 48% capacity.