Companion modelling and management of erosive runoff
Résumé
The Pays de Caux, Upper Normandy, involves a large number of places with erosive phenomena. From a socio-economic point of view, the erosive damages affect both agricultural and non agricultural lands, off-site damages being the most dramatic with muddy floods and sometime the death of people. There is thus generation of negative externalities from farmers towards the other socio-economic agents. As run-off, which flows on a slope is unaware of the limits of fields and farms, the actions to be undertaken require a co-operation between farmers. But imagining a collective agricultural land management is all the more difficult. This environmental management, commanded in a way by natural process to be controlled, do not leave actors free to choose their cooperation. At the beginning of 2006, we proposed to the local actors to set up a companion modelling approach to try, with the assistance of the tools which it proposes (multi-agents systems and role playing game), to initiate a collective management of this problem. To limit erosive runoff to various scales of investigation (farms and the catchment area), several actions are tested such as implementation of permanent grass strip or buffer pond and changes in agricultural practices. The objective of this article is to present the methodology used to build a multi-agents systems and its associated role-playing game with the help of local stakeholders. These tools allow actors to “decide” future objectives concerning catchment collective management and to imagine scenarios to reach their objectives. This research should lead to conception of new territorial organisations conciliating farming activities and environmental protection.