Drought is apparent in reduced river flows

Yampa River flowing at half the historical mean but double last year's flow at this time


The water flowing under the Fifth Street Bridge in downtown Steamboat Springs is less than half of normal, but that's significantly more than this time last year.

During the corresponding week in July 2002, the Yampa River was reduced to a trickle, flowing between 10 and 15 cubic feet per second in town. Early yesterday, the river was flowing at a relatively robust 106 cfs. Yet that number pales in comparison with the 236 cfs that is the historical mean for this date.

"This is just an indication of a drought situation showing up in reduced flows in the river," state water engineer Bob Plaska said. "We're better off than last year, that's for sure."

The Yampa peaked June 1 this year, when a half-inch of rain pushed spring runoff in the river to 5,000 cfs. That's a big number in any year. Since that time, daily flows consistently have fallen below the 93-year median.

As the river dropped day by day from late June into early July, the curve of the graph has mimicked the historic mean, but flows have ranged between 200 and 100 cfs below the norm.

Plaska said that pattern was indicative of a multiyear drought.

"Our recharge to streams from springs and everything else is just below normal," Plaska said.

The pattern began to change July 9 when the Yampa dropped below 200 cfs for the first time this summer. The gap between the historic mean and daily flows was still no more than 150 cfs, but when viewed on a percentage basis, the gap was widening.

Hay-meadow irrigation likely is the chief reason the decline in streamflow began to grow steeper.

Plaska said there was adequate water for irrigation on the main stem of the Yampa this summer. However, some farmers and ranchers on tributaries, many of them in South Routt, didn't get all the water they wanted. Trout Creek has remained free of the need to administer water rights, Plaska said. However, Oak Creek, Bear River and the three forks of Hunt Creek all were affected.

A spokesperson for the Upper Yampa Conservancy District said Yamcolo Reservoir, on the headwaters of the Yampa in the Flat Tops Wilderness, did not fill this year. The reservoir has drawn down significantly this month.

"People were able to irrigate longer than last year in some instances," Plaska said.

The drop in streamflow began to level off July 17 as hay growers shut off their ditches to begin harvesting a crop. The river spiked noticeably after an overnight rain July 20, and more moisture from the sky would not be a bad thing, Plaska said.

"Normally, you would see precipitation kicking in just about now," Plaska said. "Sunday, after that rainstorm, the river had a pretty good jump. We haven't had that," this summer.

-- To reach Tom Ross call 871-4205

or e-mail tross@steamboatpilot.com


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