Red River at Oslo, MN (Streamgage 05083500)

USGS Hydrologic Technician Dan Thomas preparing to measure discharge using an acoustic doppler current profiler (ADCP) with a manned boat on the Red River at Oslo, MN (streamgage 05083500) on April 25, 2018. The ADCP measures water currents with sound, using a principle of sound waves called the Doppler effect. The ADCP works by transmitting "pings" of sound at a constant frequency into the water. As the sound waves travel, they ricochet off particles suspended in the moving water, and reflect back to the instrument.   Date taken: April 25, 2018