Innovative Remote Sensors for Streamflow Measurement

The United States Geological Survey operates and maintains over 7000 streamgages across the United States., Conventional streamgages have several important limitations: annual maintenance cost of approximately $15k makes gaging smaller basins uneconomical, manual updating of stage-discharge rating curves is inefficient and can be hazardous to operators, and instruments in contact with the water are sometimes damaged or lost during flood events. A suite of new, non-contact sensors is proposed to address these limitations and add new, previously unmeasured variables. First, a commercially available radar system has been fielded in a very dynamic stream environment and successfully used to measure stage height and stream velocity at high temporal resolution, on the order of a few minutes. Second, a custom water-penetrating lidar has been developed and demonstrated to map 1-D bathymetry (cross-section) in clear streams. Combined with stage and velocity measurements from the radar, this will allow for computation of discharge using non-contact methods without the need to update and maintain an empirical rating curve. Once mature, these technologies promise to reduce cost and manual intervention, allow proliferation of measurements to smaller streams, and introduce previously unmeasured variables to the hydrological scientist's toolbox.