Irrigation Technology and Water Conservation: A Review of the Theory and Evidence

Farming accounts for approximately 70 percent of freshwater withdrawals worldwide, and it often constitutes the lowest value use of freshwater. Where water is scarce, advanced irrigation technologies such as drip and piped delivery systems have been promoted as water conservation technologies (WCTs) that reduce agricultural water consumption, thus releasing water to alternative uses (e.g., the environment). This article examines whether this is true, discussing how WCTs contribute, in theory and practice, to water conservation. Based on an extensive review of more than 230 theoretical and empirical papers, we argue that WCTs should not be viewed as a tool for achieving water conservation, but rather as a means for stabilizing and increasing agricultural water productivity and farmers' income in places where water is scarce. We conclude that, if the ultimate objective is water conservation, it is essential to adopt water conservation policies-that is, governance instruments aimed at reallocating available resources among uses (e.g., from irrigation to the environment)