Payment for environmental services related to aquifers: a review of specific issues and existing programmes

In Europe, payment for environmental services is increasingly perceived as an alternative to government-led incentives for promoting pro-environmental land use and attaining policy objectives of groundwater quality and quantity. The processes linking land-use decisions and ecosystem services related to aquifers (EcSA) are complex, involving different time and space scales. This raises specific challenges for the effectiveness of payment for environmental services related to aquifers (PEvSA). After defining the concepts of PEvSA, we highlight these challenges—uncertain links between land use and EcSA, spatial and temporal dimensions, monitoring and compliance issues, the invisibility of aquifers and the social equity/efficiency dilemma—and identify good practice and innovative designs for addressing them. We then review how existing PEvSA schemes throughout the world have succeeded, or not, in addressing these challenges and identify evidence of their effectiveness. We conclude that future implementation of PEvSA should pursue (i) the use of science-based approaches for determining land-use prescription; (ii) the adoption of result-oriented payments adapted to PEvSA; (iii) the use of longer term contracts adapted to water transfer time in aquifers; (iv) a finer spatial targeting of PEvSA; (v) the use of contracts with collective conditionality; and (vi) the labelling of products that generate EcSA as ways for stimulating demand. We finally call for establishing formal evidence of the impact of PEvSA on EcSA.