A Drone‐Borne Method to Jointly Estimate Discharge and Manning's Roughness of Natural Streams

Image cross‐correlation techniques, such as particle image velocimetry (PIV), can estimate water surface velocity ( v surf ) of streams. However, discharge estimation requires water depth and the depth‐averaged vertical velocity ( U m ). The variability of the ratio U m / v surf introduces large errors in discharge estimates. We demonstrate a method to estimate v surf from Unmanned Aerial Systems (UASs) with PIV technique. This method does not...