Although potential benefits and limits of scenarios are well known, few studies verify their impacts on knowledge production and public decision-making in the long term. In this paper, we perform an ex-post evaluation of land-use and land-cover change (LUCC) scenarios produced in 2004 aiming to support water management. The objective is to evaluate to what extent the impacts of those scenarios reflect expectations and to understand which factors influenced the occurrence of impacts. Moreover, we provide insights on the driving forces considered in LUCC modelling that produce plausible scenarios at a watershed level. At the time horizon of scenarios, we used semi structured interviews, combined with a quantitative comparison between observed and simulated LUCC. Results indicate that scenarios fulfilled their original purpose: to support the definition of the local water management strategy. Furthermore, they promoted a multidisciplinary perspective within land managers and facilitated the recognition of challenges and opportunities faced by local farmers. Nevertheless, they failed in creating a shared vision of the future across groups of different actors. The lessons learned from the evaluation are synthesized in guidelines that can be used to enhance impacts of any future scenarios.