b'HEADLINETECHNICAL TIPSADCP Site Selection TipsUsing an acoustic Doppler current profiling system for river measurement.JOEL EDELMAN,Senior Product and Sales Specialist SonTek, a Xylem brandOne of the most often overlookeD sourcesA general recommendation is that the measurement of errors or issues with river velocity and dischargeor installation location should be at least 5-10 channels measurements using an acoustic Doppler current profilingwidths upstream and downstream of any sources of flow system (ADCP) is site selection. disturbance, so that there is sufficient linear distance for any turbulence, eddies, up-welling, backwater effects, etc., You can get everything right in regard to the instrumentto settle out to a uniform, steady flow.operation, installation, etc., but if you have chosen a site where the basic assumptions of ADCP riverPlant growth in the channel can have an influence on flow measurements have been violated, then you will not conditions, and the bottom topography of the channel get accurate data.can also have an impact, as there could be unseen sources of significant flow disturbance below theWhen selecting a measurement site, the goal is to be ablewaters surface. to measure velocities that are representative of the mean channel velocity. Ideally, there will be a straight sectionThe following page contains some interrelated of channel of appropriate length that is free from flowconsiderations when using a multi-beam acousticdisturbance caused by bends in the channel, obstacles inDoppler current measurement system.the water, inflows, outflows, etc. Uniform vs. Non-Uniform FlowUniform Non-uniformFLOWContact the SonTek Technical Support Team: Support@SonTek.com58 MISSION: WATER'