Part of the Understanding Our Environment project that is designed to engage students in investigating specific environmental problems through concrete activity and direct experience, this unit contains a role-play activity in the form of a public inquiry into the cause of a fish kill on a river that runs through the fictional town of Oakwood. A variety of past and present, actual and potential problems are suspected, and the need for remedies is considered. Students represent the interests and concerns of townspeople and of special groups and in the process learn to appreciate the complexity of environmental issues. Objectives include: identifying a variety of possible causes of freshwater pollution; considering the impact of human activities on a waterway; learning about various aspects of water use, water quality, and water pollution; learning about water conservation and wastewater treatment; engaging in problem solving, analysis, and debate; considering the roles and responsibilities of citizens and businesses; developing an awareness of the different perspectives that are brought to environmental issues; experiencing the need to consider costs, risks, and benefits in attempting to solve problems; and recognizing the importance of accurate information and an informed citizenry in protecting and improving the environment. (JRH)