Selecting irrigation water pricing alternatives using a multi-methodological approach

Public decision-makers in charge of designing and implementing the irrigation water pricing policy required by the Water Framework Directive have a difficult task to select between a set of possible alternatives. The main objective of this study is to develop a multi-methodological approach that allows supporting decision makers to choose the alternative that achieves the best compromise solution in irrigated areas between a set of socio-economic and environmental attributes. To this end, a case study is applied in two irrigation districts in the province of Palencia (Spain). The proposed approach takes the following steps: (a) selection of potential alternatives to be evaluated, (b) classification of farmers into homogeneous groups, (c) simulation of irrigated farmers behaviour when facing different water pricing alternatives via positive mathematical programming models, (d) selection of the socioeconomic and environmental criteria for the analysis and (e) application of a hybrid multi-criteria decision making model to rank the alternatives integrating the Analytic Hierarchy Process and the modified Technique for Order Preference by Similarity to Ideal Solution. The results show the effectiveness and potential utility of the proposed methodological framework for irrigation water pricing instruments’ selection. The empirical results of this research indicate that those pricing instruments which consider the current consumption of irrigation water allow for a better compromise solution instead of the tools that price water irrespective of current consumption. Furthermore, the results also suggest that the irrigation water pricing policy could be implemented in function of the different farming districts, rather than establishing one single type of irrigation water pricing instrument and tariff level for a whole river basin, as these would not allow to achieve the same degree of compromise solution in different farming-districts.