Arkansas Stream Gauging Program
using SonTek FlowTracker

June, 2005 - The diverse range of environments found in Arkansas -- from mountainous streams (Figure 1) to delta rivers and both flood and drought conditions -- provides significant measurement and procedural challenges for field hydrologists. In an effort to improve their level of service to the public, the U.S. Geological Survey's (USGS) Arkansas Water Science Center began using the SonTek FlowTracker as part of their stream-gauging program in 2001. The Science Center has nine Hydrographers who routinely make field trips as part of the data collection operation.

In the past, all measurements had been made using mechanical propeller meters, such as the Price AA and Pygmy meters. By 2005, all mechanical meters were replaced with SonTek FlowTrackers. All the Hydrographers now use the FlowTracker exclusively for measuring discharge in wadeable streams (Figure 2). Use of the FlowTracker has not only increased the operational efficiency of the Water Science Center, it has also enhanced their ability to make measurements in environments previously thought immeasurable.

The key reasons behind the switch to the FlowTracker were:

• Improved operational efficiency - Due to the elimination of note-taking, calibration, and manual calculations, field personnel can now make more stream measurements in the same amount of time.
• Elimination of maintenance - As the FlowTracker has no moving parts, there is no need for any ongoing maintenance by the user.
• Reduce training times - New field personnel can be trained in how to use the FlowTracker in less than half the time it used to take for mechanical equipment.
• Higher measurement accuracy - The high precision of the FlowTracker results in better rating definition.
• Increased range of measurement conditions (extreme events) - The FlowTracker is able to accurately measure stream flows in the shallow and slow-moving drought environment.

	Figure 1. Common stream-gauging conditions in Arkansas.
	Figure 2. The integrated display and processor lets you easily compute streamflow on the fly.

Note: Use of this instrument by USGS personnel does not imply endorsement by the USGS.

• FlowTracker Handheld ADV

For information about the USGS policy on FlowTracker discharge measurements:

• The following link is to a Technical Memorandum issued by the U.S. Geological Survey's Office of Surface Water. This memorandum [pdf format] describes the USGS policy on the use of the FlowTracker for discharge measurements. The information presented in this memorandum is a courtesy from the USGS, and should not be construed as an endorsement. Additionally, this memorandum is provided "as-is"; that is, the USGS does not provide support for this memorandum outside its own agency.
  http://hydroacoustics.usgs.gov/memos/OSW2004-04.pdf