MODELLING TOOLS FOR THE HARMONIZATION OF THE WATER FRAMEWORK DIRECTIVE AND THE COMMON AGRICULTURAL POLICY

Pressures due to agricultural activities play a major role in the status of water resources systems throughout Europe and other countries. The evaluation of the effects of agricultural policies is therefore a key problem in water resource planning and management. The work presented in this paper is an attempt to include the predictable effects of the Common Agricultural Policy (CAP) in the planning process of water resources at the basin scale expected by the Water Framework Directive (WFD). The approach is based on the combined use of three models: (i) an economic model used to predict the likely land use scenarios following the CAP reform; (ii) a spatially distributed hydrological model for the assessment of the irrigation water requirements; and (iii) a decisional model supporting stakeholders and decision makers in the planning process. This paper presents an application to a pilot study area in Northern Italy, the Adda river basin. The results highlighted how the CAP may produce an adjustment on the agricultural sector, with a shift towards more extensive land uses (set aside and grassland) and to a greater productive diversification (increase of minor cultivations, such as soya beans). The predicted changes in land use type and distribution are shown to have a limited but significant influence on water requirements, with a generalised decrease of their value, which may exceed 10% in some areas. In turn, the decrease of irrigation demand can be exploited to achieve a higher degree of satisfaction of other users of the water resource system. This case study showed that the complexity associated with using a set of different modelling and optimisation tools to support water resource planning process can be managed. However the effort is justified only if stakeholders involvement takes place from the early stages and is exploited not only in the identification of the eligible measures and in the choice of the indicators, but also in the definition of the model characteristics and in the validation of their results.