Managing irrigation supplies effectively under interrupted electricity supply: Lesson from an arid region of India

Abstract

Groundwater extraction through electrically operated tubewells offers a resilient source of irrigation supply in arid regions especially during droughts. However, interrupted and low-voltage electric supply with limited availability and frequent trips increases repair and maintenance costs of tubewell irrigation and reduces tubewell discharge resulting in less-efficient and non-uniform water application. This study evaluates performance of an indigenous system of groundwater irrigation that was evolved over the generations in arid region of Gujarat, India to address electricity-triggered issues of irrigated agriculture. In this system, groundwater extracted during electricity availability hours is stored in surface reservoirs for later supplying to irrigate crops under gravity flow irrespective of electricity availability. A comprehensive survey of the indigenous system is conducted in a village of Gujarat to make inventory of all tubewells and storage reservoirs about their depth, size, pump type and horsepower, command area, crops, irrigation timing and frequency, etc. Discharge of tubewells was measured and their locations were recorded. Results revealed that the indigenous system is advantageous over the direct tubewell-irrigation in terms of 37.4% higher water-delivery rate and 50% more average irrigation capacity. These findings prove adequacy of the indigenous system in regulating irrigation supplies to deal with electricity-induced intricacies of irrigated agriculture. Amount of water lost through unit area of earthen (seepage and evaporation ∼2.77 m) and masonry (evaporation ∼1.22 m) reservoirs collectively accounts for a negligible proportion (0.9%) of groundwater draft. Furthermore, a methodology is devised to precisely estimate village-level groundwater draft for irrigation, which is validated by 0.9% deviation between observed and predicted values of groundwater draft. Moreover, the indigenous system is simple, cost-effective and easy to implement in other parts of the world especially in arid regions of the developing countries where low-voltage and intermitted electricity supply persists.