Benefits and Costs of Managed Aquifer Recharge: Further Evidence

Abstract

Managed Aquifer Recharge (MAR) provides an integrated solution that allows aquifer storage to complement surface water storage. Cost–benefit analysis provides a systematic method for comparing alternative water infrastructure options. When market valuations of water infrastructure are unavailable, levelised cost is a widely accepted method of comparing MAR with alternative solutions. Benefits of MAR can be estimated by the cost of the cheapest alternative source of supply or the value of production using MAR. This article presents quantitative analysis of levelised costs and benefit cost ratios of 21 MAR schemes from 15 countries, and qualitative assessment of additional social and environmental benefits. MAR schemes recharging aquifers with natural water using infiltration basins or riverbank filtration are relatively cheap with high BCRs. Schemes using recycled water and/or requiring wells with substantial drilling infrastructure and or water treatment are more expensive, while offering positive BCRs. Most MAR schemes have positive or neutral effects on aquifer storage and condition, water quality, and environmental flows. Energy requirements are competitive with alternatives. This paper demonstrates strong returns to investment in the reported MAR schemes. MAR provides valuable social benefits and contributes to sustaining groundwater resources where extraction is managed.