Flow measuring devices in surface irrigation for enhancing agricultural water productivity

Judicious use of water plays a vital role in enhancing its productivity in agriculture. In India, surface irrigation covers about 88% of the irrigated area with application efficiency ranging from 30% to 40%. Therefore, it becomes imperative to improve water application efficiency of canal commands and other areas under surface irrigation. Water application efficiency can be improved by minimizing conveyance losses and by judicious irrigation scheduling pertaining to different crops, which can be accomplished by accurate measurement of irrigation water. Measurement of irrigation water supplied to farmlands not only assists in the saving of water but also enhances water productivity in agriculture. The most popular device for measuring irrigation water in field channels is the Parshall flume, which has undergone a series of modifications to simplify its construction, improve the accuracy of measurements and reduce its cost leading to its wider acceptance by the stakeholders. Thus, it becomes imperative to deve­lop an accurate, low-cost and portable flow-measuring device for enhancing agricultural water productivity. Moreover, a review of the literature reveals limited availability of portable and digital flow-measuring devices for real-time measurement of surface irrigation through field channels. Nonetheless, it is established that the use of flow-measuring devices in surface irrigation will not only save water but also expand the area under irrigation, ensure its sustainability and improve agricultural water productivity.