Runoff news: Rio Grande basin will peak early

A picture named riograndebasin.jpg

From the Pueblo Chieftain (Matt Hildner):

Division Engineer Craig Cotten said the early runoff may be the result of dust storms from the Colorado Plateau and Great Basin that have dirtied the snowpack in the San Juan Mountains, reducing the snow’s ability to reflect sunlight. While Cotton was sure to tell the Rio Grande basin roundtable this week that the scenario was a theory, he didn’t dispute that the San Juan’s snow has been dustier this season. “If you look up toward the mountains, you can really tell,” he said. “It’s not white.”

Gauges on the Rio Grande near Del Norte show the river had peaked at nearly 6,200 cubic feet per second on May 8. The historic average for the gauge, based on 111 years of records for that day, is nearly a third of that amount. Cotton said in normal years, the Rio Grande experiences two periods of peak flows, one in mid-May for the foothills and another in early June for higher elevations. The early runoff could pose a problem, Cotten said, noting that some potato farmers had yet to even get their crop in the ground. “That’s kind of the fear is that we’re seeing a lot of water right now,” he said. “But in a couple of weeks when we’re supposed to see our high runoff and when everyone counts on that high runoff our rivers might be dropping significantly at that time,” he said…

Larry Walrod, a senior meteorologist and hydrology program manager at the Pueblo office for the National Weather Service, agrees with the theory. “That’s got to be a part of the early melt out,” he said. But he also sites the sublimation of the snowpack, or its exposure to hot dry winds that lead it to vaporize into the air. Moreover, temperatures in the eastern San Juans were warmer than normal in March and April. Mean temperature for March in the San Juans was three to four degrees above the month’s normal mean, he said, while the mean temperatures in the area for April were two to three degrees above the normal mean.

Meanwhile, here’s the news from the Roaring Fork Watershed via the Aspen Times:

Releases from Ruedi, east of Basalt, will be increased in increments of 50 cubic feet per second over the next few days until the flow reaches 650 cfs on Monday, according to the U.S. Bureau of Reclamation, which manages the reservoir. The release rate is likely to remain at or near that level through Memorial Day, the agency said. The high flows severely limit the ability to fish in the Fryingpan River. The river is expected to be at about 350 cfs by Friday afternoon, then continue to rise through the weekend. The Bureau of Reclamation anticipates that Ruedi Reservoir will fill to capacity this summer despite the special releases for the imperiled fish.

Leave a Reply