A Modelling Solution for Developing and Evaluating Agricultural Land-Use Scenarios in Water Scarcity Contexts

To meet sustainability challenges, regional water management and planning require approaches that assess the land-use visions of various stakeholders using their own evaluation criteria. Models and information systems are keystones in such integrated assessment activities. SPACSS (the SPAtial Cropping System Scenarios builder and evaluator) is a modelling solution that aims to help decision-makers evaluate normative land-use scenarios. A prototype of SPACSS was developed to explore concerns raised by a dam-building project in south-western France, specifically the relation between cropping system distribution and water uptake. This paper presents the initial steps of SPACSS development by scientists and agricultural experts and its evaluation by users through alternative scenarios of maize cropping (altering either its precocity or management to reduce irrigation). SPACSS can represent a wide range of land-use scenarios and aggregate impact indicators at several spatial and temporal scales. Although SPACSS served as a solid support for discussions with stakeholders and decision-makers, it needs modifications to represent more realistic, and thus more complex, land-use scenarios. These modifications will make SPACSS potentially valuable for dealing with a variety of issues concerning agricultural landscapes, far beyond the single question of quantitative water management.