A systematic approach to analyzing conflicts between planning agencies and citizen groups over water and related land-use alternatives is presented. The methodology consists of building dynamic system models of the institutional and economic factors involved in a conflict, and using the models to make quantitative and qualitative predictions of the course of events. Organizational goals, constraints, strategies and interactions are represented by dynamic feedback models, which are based on information and data provided by participant-observers who are actively involved in the conflict. The methodology was applied to two case studies in Massachusetts; the proposed diversion of the Connecticut River at Northfield Mountain, and wetlands protection in the Neponset River watershed (Traphole Brook). A computer simulation model of land-use economics in a typical Massachusetts suburban community is described. The methodology should be of interest to policy researchers and planners concerned with public participation in water resources planning. (Author)