Financial Feasibility Constrains Water Conservation in Agriculture on the Indo-Gangetic Plain

Abstract:

A number of water conservation measures in agriculture have been proposed to produce more food with less water. However, the extent to which the benefits compensate the costs of these measures is poorly quantified. A complicating factor is that losses from inefficient use of water upstream are often reused downstream so that benefits of water conservation measures tend to be overstated. Here, we introduce a novel method to compare the costs of water conservation measures with the added value that reallocation of water savings might generate if used for expansion of irrigation. Based on detailed water accounting through the use of a high-resolution hydrology-crop model, we modify the traditional cost curve approach with an improved estimation of demand, increasing marginal cost per water conservation measure combination and add a correction to control for impacts on downstream water availability. Applied to three major river basin, the Indus, Ganges and Brahmaputra, we show that only just over 20% of potential water savings would be realised if financial feasibility is taken into account; the majority of water conservation measures are simply too costly. Despite these limited water savings and the modest expansion of irrigation they would allow, their implementation would improve farm profits in a region where farming profitability is low. Controlling for the impact on return flows is important and more than halves the amount of water available for reallocation. With increasing water stress expected in a changing climate and increasingly urbanized world, our results have important implications for prioritizing adaptation investments that make financial sense to farmers and decision-makers.