Originally published on April 4, 2018 4:30 pm
The Colorado River Basin is likely to see one of its driest spring runoff seasons on record this year, according to federal forecasters.
Scientists at the Salt Lake City-based Colorado Basin River Forecast Center say current snowpack conditions are set to yield the sixth-lowest recorded runoff into Lake Powell since the lake was filled more than 50 years ago.
The April forecast projects inflow to Lake Powell, the first major reservoir that impounds the river’s water as it flows from the Rocky Mountains to Mexico, to be 43 percent of average.
As the winter progressed, water managers, farmers and cities hoped for a “miracle” month to boost dwindling snowpack. Those storms never quite materialized. Now, a few days into the historic runoff period, forecasts are less of an educated guess about the far off future and more a reflection of the almost present.
“At this point getting close to average is a pretty unlikely scenario,” says Greg Smith, a CBRFC hydrologist.
Climate and weather records give little hope of spring weather robust enough to make a difference, according to Smith. At this point, the Colorado River Basin has less than a 3 percent chance of catching up to an average year.
This pattern will feel familiar to those who watch the Colorado River closely. Of the 15 driest years on record in the river’s Upper Basin, which includes the mountains of Colorado, Wyoming, Utah and a small portion of New Mexico, nine of those years have occurred since 2000. Of the top five driest, three have been since 2002.
The dry winter has been felt acutely in southwestern Colorado, northern New Mexico, Arizona and central and southern Utah. Measurement sites near the headwaters for the San Juan, Dolores and Gunnison Rivers have reported the lowest precipitation on record since October.
Low soil moisture throughout the watershed has the possibility of lessening spring runoff even further. Dry soil sucks up melted snowpack before it can reach a major stream, meaning the parched landscape saps even more of the river’s normal flow.
The low runoff means the possibility of a shortage on the Colorado River could be declared sooner than later. That declaration would be triggered if Lake Mead, another major reservoir outside Las Vegas, dips below 1,075 feet in elevation. The latest operational plan from the Bureau of Reclamation projects the lake to be below that threshold in 2019.
There’s still a small chance of a modest snowpack recovery in the Rockies.
“A series of storm systems are on the horizon as we enter April,” reads the CBRFC’s April forecast. “The question is just how far south the precipitation impacts will occur.”
This story is part of a project covering the Colorado River, produced by KUNC and supported through a Walton Family Foundation grant. KUNC is solely responsible for its editorial content.
Copyright 2019 KUNC. To see more, visit KUNC.
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