This environmental education guide focuses on man's impact on the estuary. The program contained in the guide is developed around the following nine questions: (1) What is a definition of the ecosystem being investigated?; (2) What are some of the biotic and abiotic features of the ecosystem and how do these features interrelate?; (3) Where are some specific locations of the ecosystem being investigated?; (4) What biotic and abiotic features in the ecosystem have changed and are undergoing change?; (5) What are the natural factors causing change in the ecosystem and how have they been brought about?; (6) What are the man-made factors causing change in the ecosystem and how have they been brought about?; (7) What are the results of changes?; (8) What, if any, new changes are needed in the ecosystem?; and (9) How might these needed changes to the ecosystem be brought about? Following the inquiry questions is a section of learning activities, which also includes resources, evaluation strategies, and teacher suggestions. The final section, teacher comments, is material which will help initiate and implement this program in to the existing curriculum. (TK)