Evaluation of Ultrasonic Sensor for Flow Measurement in Open Channel

Accurate measurement of flow depth in an open channel on a real-time basis is the prime factor leading to more accurate quantification of discharge by the flow measuring device. The aim of present study was to evaluate the ultrasonic sensors (viz. HC-SR04 and JSN-SR04T) for depth of flow and corresponding discharge rate measurement in irrigation channel of canal command. The effect of ambient temperature on ultrasonic sensors was also investigated for irrigation channel hydraulic response measurement. It was observed that the performance of calibrated and temperature compensated sensors was better than the uncalibrated ones. Moreover, the performance of JSN-SR04T was better with mean absolute deviation (MAD: 0.21 ± 0.01cm), root mean square error (RMSE: 0.82 ± 0.01) and mean absolute percentage error (MAPE: 0.46 ± 0.09) compared to HC-SR04 sensor with MAD (0.36 ± 0.07), RMSE (0.43 ± 0.08) and MAPE (1.54 ± 0.82), respectively. Hence, JSN-SR04T ultrasonic sensor was used in the developed sensing system for the measurement of flow depth. It was observed that the system measured flow rate when compared with the observed flow resulted in prediction error estimate MAD (0.13 ± 0.05 lps), RMSE (0.16 ± 0.05) and MAPE (2.09 ± 1.16) and coefficient of determination (R2: 0.99) for flow rate ranging from 2 to 20 lps. Overall, the study resulted in the development of a novel and economically viable open channel digital flow sensing system to measure discharge rate passing through the flume. The developed sensing system will assist stakeholders in enhancing surface irrigation water use efficiency in canal commands.