Shallow-water flow measurements around hot springs in Yellowstone National Park with FlowTracker

August, 2001 - Within Yellowstone National Park, there are several hot springs and small streams where water depths are on the order of a couple of inches or less. Traditional methods of measuring water velocity are neither practical nor effective under these conditions. With this in mind, the Yellowstone Center for Natural Resources (YCNR) required a current measurement instrument that is portable enough to fit in a backpack (many of the sites are only accessible by foot), readable in bright daylight, has sufficient internal recording capability, and is able to withstand the high water temperatures sometimes present in the hot springs.

In August, 2001, a demonstration of the SonTek FlowTracker was set up to evaluate the feasibility of the Handheld-ADV for this application. Observing the demonstration were representatives from the U.S. Geological Survey, the University of Montana, and the National Park Service. SonTek's Chris Ward made the trip to Yellowstone for the field demonstration.

One of the sites chosen for the evaluation was Beryl Spring, which is 15 miles south of Mammoth Hot Springs in Yellowstone. Normally accessible by the public, Beryl Springs was off-limits because park officials considered it to be an explosion hazard. As such, personnel form the YCNR make frequent observations of environmental parameters around the hot spring to better understand this phenomena. One of the important parameters is discharge from the hot spring itself.

A wading rod was not necessary to make the measurements because the water is so shallow. Great care had to be taken in where one stood and where the ADV probe was placed so that hot steam from the ground did not burn the observers' skin (Figure 1).

The ADV probe was positioned in several different sections. Usually, only one velocity measurement was possible in a cross-section as the water was so shallow. The observers were intrigued by the FlowTracker's ability to output two-dimensional velocity, water temperature, and reflected echo intensity to the LCD screen (Figure 2).

By all accounts, the demonstration was a success, and the YCNR was satisfied with the FlowTracker performance. An order was soon placed by the YCNR.

	Figure 1. FlowTracker being used in hot spring.
	Figure 2. The integrated display and processor lets you easily compute streamflow on the fly.

• FlowTracker Overview