Extensive use of computers in water-resources planning makes the more efficient use of available information increasingly possible. It also promotes an iterative planning process by making analysis and evaluation more convenient. The concept of collaborative planning is an idea that has had limited use because of the complexities that prevent people with different backgrounds from communicating. A collaborative planning-support system (CPSS) integrates available computer technologies with modelling and analysis tools in a user-friendly environment, thereby enhancing communication between the proponent for resource development and affected or interested parties. CPSS does not provide solutions but empowers participants by identifying areas of common understanding, encouraging them to explore solutions and reach a consensus. Using the concept of 'grounded theory' from social sciences, the CPSS module described in this paper is a tool for developing evaluation criteria. Use of the concept is illustrated by an example from northern Manitoba which focuses on fish habitat issues relating to a hydropower development project.