Water conservation in irrigation can increase water use

Abstract

Climate change, water supply limits, and continued population growth have intensified the search for measures to conserve water in irrigated agriculture, the world's largest water user. Policy measures that encourage adoption of water-conserving irrigation technologies are widely believed to make more water available for cities and the environment. However, little integrated analysis has been conducted to test this hypothesis. This article presents results of an integrated basin-scale analysis linking biophysical, hydrologic, agronomic, economic, policy, and institutional dimensions of the Upper Rio Grande Basin of North America. It analyzes a series of water conservation policies for their effect on water used in irrigation and on water conserved. In contrast to widely-held beliefs, our results show that water conservation subsidies are unlikely to reduce water use under conditions that occur in many river basins. Adoption of more efficient irrigation technologies reduces valuable return flows and limits aquifer recharge. Policies aimed at reducing water applications can actually increase water depletions. Achieving real water savings requires designing institutional, technical, and accounting measures that accurately track and economically reward reduced water depletions. Conservation programs that target reduced water diversions or applications provide no guarantee of saving water.agriculture ͉ sustainability ͉ institutions ͉ hydrology

Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley

“…In the CV, ∼50% of crops are still produced under flood irrigation (36). The ability of improved irrigation efficiency to result in real water savings has been questioned because much of the irrigation excess is thought to return to streams or replenish aquifers (37,38), and the saved water is often used to expand irrigation or irrigate more water-intensive crops (38,39).…”

Tapping unsustainable groundwater stores for agricultural production in the High Plains Aquifer of Kansas, projections to 2110

“…Realizing the potential of improved future prospects requires collective action to design solutions that reduce aquifer depletion today while rewarding participation (34,35). The scenarios in Fig.…”

Can a change in cropping patterns produce water savings and social gains: A case study from the Fergana Valley, Central Asia

“…In this paper, water savings are defined as the reallocation of water from a current use that produces low, negligible, or negative benefits, to those that generate higher benefits (Molden, 1997;Seckler 1996). Managing the irrigation demand by reducing the beneficial use in agriculture may not always bring real water savings (Ward and Pulido-Velazquez, 2008). It may result in lowering the productivity of the use of thermal and land resources, affecting instream use values (Ward and Booker, 2003), increasing salinity (Khan and Hanjra, 2008), and negatively impacting ecosystem health (Karimov et al, 2014), but it may also deliver other socioeconomic benefits including incomes, employment, revenue, and gains in food security (Molden et al, 2010) for both rural and urban consumers.…”