The water quality of the catchments that supply drinking water to the town of Brienon (France, Northern Bur-gundy) is degraded and the water catchment area has been labeled as priority vulnerable zone. In this mostly agricultural area, it means that the farmers are expected to implement different practices with less harmful envi-ronmental impacts and that a steering group will be built to orient and control these changes. In this paper and focusing on the nitrate issues of the catchment area, we tell how we have used this context to build a dynamics inside the area. The steering group and the farmers of the area have learned to work together with the help of the methods and tools built by the local Chambre d’Agriculture (CA Yonne) and the French national insti-tute of agricultural research (Inra Grignon). We first explain how the steering group has agreed that 8 volun-teer farmers build an action plan for the area and how these farm-ers have worked to do that. We then insist on the key role of two instruments to not only make propositions but also follow their dynamic implementation, success and failure. First we present how we designed a dashboard that follows the actions implemented each year by the farmers (and other actors of the area) to improve the water quality and that follows the effect of these actions with regards to the water quality in the area. This tool is an animation tool both with the farmers and between the farmers and the steer-ing group. We also insist on the role played by the observatory of the field states: linked with the dashboard, it focuses on the results achieved so far in each plot in relation to the expected results. We finally insist on the current state of the local dynamics and what remains to be done and achieved.