Development of a digital open channel flow measuring device for surface irrigation

ABSTRACT The irrigation sector, being the largest user of water in India, requires 40% more water by 2050 to meet the food demand of the ever-increasing population. Hence, it becomes imperative to implement judicious water management technology to save water and enhance agricultural water productivity. Keeping this in view, the present study developed a portable, low-cost digital openchannel flow measuring device (a modified flume) to measure the discharge rate and volume of irrigation water. The modified flume was designed, fabricated, and tested at the hydraulic flume testing facility of the Water Technology Centre, ICAR-IARI, New Delhi. The device features two configurations: (1) a straight contraction with a curved diverging section and (2) a curved contraction with a straight diverging section. Both configurations were tested with three contraction ratios: 53.33%, 61%, and 70%. It was observed that the device with a 70% contraction ratio straight converging section (30° angles) and a curved diverging section was the best among all experimented designs. Subsequently, a digital sensing system with a waterproof ultrasonic sensor, microcontroller, data logger, and temperature sensor was mounted. The validated rating curve was embedded in the microcontroller through programed code to display the flow depth, discharge rate, and supply volume in a period of time. Nonetheless, the developed device can be tested under different channel shapes and sizes to ascertain its measurement accuracy and wider applicability.