SonTek Demonstrates RiverSurveyor to USGS and CDWR

SonTek conducted a demonstration of the RiverSurveyor discharge measurement system to hydrologists from the Sacramento U.S. Geological Survey (USGS) and the California State Department of Water Resources (CDWR). The RiverSurveyor demonstration was done at the request of the USGS and included simultaneous discharge data collected with SonTek's RiverSurveyor system and another respected Doppler profiler⁽¹⁾. The systems were mounted adjacent to each other on a boat used by the USGS for real-time river discharge measurements (Figure 1).

Figure 1. Survey boat with adjacently-mounted profilers

Discharge measurements were collected using standard USGS measurement techniques. Each profiler was set up using identical criteria. The RiverSurveyor's Windows-based interface and its single-mode of operation made it easy to enter the only parameters required: depth cell size and number, instrument depth, salinity values, blanking distance, and profile estimation methods (for top and bottom unmeasured sections).

The demonstration consisted of seven consecutive discharge measurements collected within a 30-minute period. During the measurements, stream velocity averaged about 15 cm/s, and stream depths averaged about 3 m.

The data shown in Figure 2 have not been edited or modified and represent actual discharge values measured by each instrument while in the field⁽²⁾. The data show that both profilers generally compare very well. Minor deviations can be attributed to slight differences in starting and ending points. The robustness of the RiverSurveyor is demonstrated by the fact that it measured discharge consistently and independently of the boat speed.

Figure 2. Comparison of discharge measurements

• RiverSurveyor

¹ The second profiler was used as a "check" measurement because the demonstration was not conducted near a USGS discharge gauging station.
² Discharge data for the second profiler was provided to SonTek/YSI as provisional data from the USGS.