High-tech mini river raft measures Yampa River streamflow | SteamboatToday.com

High-tech mini river raft measures Yampa River streamflow

Yampa River rises, data uploads





Jeff Foster of the the USGS launched a high-tech streamflow measuring device called an Acoustic Doppler Current Profiler into the Yampa River at Fifth Street to make precise measurements of the river's flows.
Tom Ross

— The nearly one inch of rain that fell May 9 and intensified after midnight May 10 caused the Yampa River to rise significantly. However, the Colorado Basin River Forecast Center in Salt Lake City was projecting Tuesday morning that, in spite of a forecast for warming temperatures, the river's flows will calm as the weekend approaches.

The Forecast Center reported the river had risen to 4.98 feet at the Fifth Street Bridge in Steamboat as of 9 a.m. May 10 — still well below the flood stage of 7 feet at that point on the river.

At that level, the river was flowing at 2,300 cubic feet per second, well above the median flow for the date of 1,320 cfs. However, the Yampa is expected to settle back to the range of 1,500 cfs by 9 a.m. Wednesday and remain there until the weekend, when river flows are expected to bump up moderately.

Jeff Foster, a hydrologic technician with the U.S. Geological Survey in Grand Junction, launched a high-tech streamflow measuring device called an Acoustic Doppler Current Profiler, or ADCP — a device which resembles a smaller version of a yellow river raft — into the Yampa at Fifth Street Tuesday morning to make precise measurements of the river's flows.

The ADCP works in the same way as sonar, using the Doppler effect of sound waves generated by particles in the water column to measure velocity with precision.

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There were reports of tributary creeks in West and South Routt flowing over their banks, but Routt County Director of Emergency Management Bob Struble said he did not view them as serious flooding threats.

"Oak Creek and Trout Creek have come up," he said. "I think there's a lot of standing water in the fields resulting from all the rain and the saturated ground."

Weather watchers in the Steamboat vicinity recorded 24-hour precipitation as of 7 a.m. Tuesday ranging from .72 inch nine-tenths of a mile north of the city, to .91 inch at a rain gauge 1.9 miles to the east. South Routt did not see as much rain, with one rain gauge reporting four-tenths of an inch.

The National Weather Service is expecting warmer and drier weather through Sunday, with a return to a wet forecast and cooling trend early in the work week.

"An approaching low pressure system brings a chance of showers and thunderstorms, mainly across (Northern Colorado) on Sunday," NWS meteorologist Norvan Larson predicted. "Chances increase early next week as the low settles over the area, bring temperatures back down to season norms."

The significant rainfalls of May 6 through 11 falling on a substantial snowpack still hanging on in the Park Range east of Steamboat raises questions about when the Yampa will peak and begin the slide into summer.

There have been years when the Yampa had already peaked by this date, including 2015, when the Yampa topped out at 3,550 cfs on May 7, and all-time record May 2015 precipitation helped keep the Yampa at healthy flows in spite of snowpack that began the month at 55 percent of median.

But a review of historic data on peak seasonal flows confirms that, even in spring runoff periods, when the river has peaked above 5,000 cfs, the dates of those events have been spread out from late April to June 7.

The Yampa didn't peak until May 29 in 2014, and that year, it topped out at 4,850 cfs. One need only go back to the poor snow year of 2012 to see just how early the river can peak. The Yampa went no higher that season than the 1,570 cfs recorded by the USGS on April 27.

The most recent spring flood occurred in 2011, when the Yampa jumped its banks and flowed around the parsonage at the Steamboat Christian Center, and Soda Creek also left its banks, flowing through Little Toots Park. That year, the river peaked June 7 at 5,200 cfs.

To reach Tom Ross, call 970-871-4205, email tross@SteamboatToday.com or follow him on Twitter @ThomasSRoss1