Multicriteria decision analysis (MCDA) methods have been recently applied in many environmental problems. Major aims have been to structure and to analyse multifaceted and complex problems, to compare incommensurable impacts and to clarify the preference order of alternatives. Most MCDA tools concentrate on aiding the process of choice among alternatives. The choice usually occurs at the end of the decision-making process, but MCDA tools can also assist earlier in the process. In this article, we present a new MCDA-based method in order to create watercourse regulation alternatives, which meet the objectives of stakeholders. The method is comprised of three elements: (1) framework for the planning and learning process partly based on the Image Theory, (2) analysis and evaluation of ecological, social and economic impacts of regulation, and (3) visual interactive Excel implementation of value-tree analysis (REGAIM-model). We show how the method was applied in a complex watercourse regulation development project in Finland. Altogether 36 face-to-face computer-aided interviews were undertaken with the REGAIM model with representatives of different stakeholder groups. We present the main results of the interviews and discuss how these interviews supported generation of new watercourse regulation alternatives. We also describe the advantages of the new approach in the participatory watercourse management, and discuss the applicability of Image Theory in the watercourse regulation context. Copyright © 2006 John Wiley & Sons, Ltd.