Experimental system for real-time discharge estimation using an image-based method

This study describes an experimental system for making continuous river discharge measurements using real-time, image-based, noncontact technologies. The system uses particle image velocimetry (PIV) to estimate displacements of river surface flow tracers on recorded images. The velocity-area method is then applied to estimate discharge at a cross section of known bathymetry. The system has been operational since August 2004, making continuous discharge estimates at an experimental site on the Iowa River. Based on preliminary results from its first 23 months of operation, the authors identify illumination of the river surface by natural lighting, wind, and rain effects, PIV parametrization for variable flow conditions, and stage measurement, as the most pressing challenges related to image-based discharge measurement. The experimental data archive generated from the continuous long-term operation at the site will facilitate the research needed to address these problems and improve the reliability of image-based discharge measurement technologies.