A mechanic-electronic sensor for automatic measurement of sediment-laden flow rate from erosion runoff plots

Summary Erosion and hillslope surface/subsurface hydrology studies are in need of temporal measurement of flow rates, where sediment-laden runoff normally presents. A new method/sensor capable of taking automatic measurements of sediment-laden runoff flow rates is presented. Mechanical structures, hydraulic backgrounds and computational principles of the suggested sensor are discussed in details. Theoretical-analysis of surface hydraulic formed the basis for formulating a function for calibration of the sensor to clear water flow. A functional relationship was derived for adjustment of flow rates of sediment-laden water. Calibration experiments validated the hydraulic relationship between the flow rate of clear water and the sensor’s outputs. The adjustment function of flow rate produced highly accurate measurements of sediment-laden runoff. Applications of the newly-developed flow senor to a laboratory watershed exposed to rainfall evens of both constant and variable intensities demonstrate that the sensor is highly accurate and capable of taking continuous measurements of the transient hydrographic processes of runoff. The accuracy and reliability of the flow device with labor and time saving advantages will be useful in hillslope hydrological monitoring for research and other purposes.