Low spring runoff, low flood threat in forecast
The Colorado River isn’t expected to swell in water volume as much as normal during the upcoming spring runoff, according to a National Weather Service forecast.
Also, flood potential because of melting snow is not high for now for most of western Colorado and eastern Utah, according to the agency’s spring flood and water resources outlook.
With snowpack levels below average in the Upper Colorado River Basin, the forecast is for runoff from melting snow to range from 70 to 90 percent of average within much of the river and its tributaries.
The volume at Cameo is projected to be 75 percent of average, and the volume forecast for the Gunnison River in Grand Junction is 83 percent of average.
Flows into Lake Powell are expected to be 70 to 75 percent of normal.
All of the forecasts are based on natural flows and don’t reflect possible influence of reservoir operations. The forecasts use data from the Natural Resources Conservation Service, the Colorado Basin River Forecast Center and the Climate Prediction Center.
Bryon Lawrence, a hydrologist with the National Weather Service in Grand Junction, said good snow seasons the past two winters helped boost water levels in reservoirs.
“We’re not in bad shape right now in terms of water supply,” he said. “Where we have problems here is where we have consecutive years of drought, because then the reservoirs do get low, and then we have problems with water supply and irrigation.”
Snow levels on Grand Mesa, which supplies municipal water to Grand Junction and Palisade, also are in decent shape, he said. The snowpack level at Mesa Lakes on Thursday was 88 percent of normal, the Conservation Service reports.
Lawrence noted estimates are still early. Runoff can be affected by snow that normally can fall well into April.
Rainstorms or unseasonably warm temperatures also can affect volume and increase flood threat.
The forecast includes a projection of equal chances of above- or below-normal precipitation through April.
A factor is what effect the ongoing El Niño will continue to have. That pattern generally results in questionable precipitation benefits to central and northern Colorado, but has contributed to recent big storms in the southwest part of the state, Lawrence said.