From September 18 to 21, 1989, the American Geophysical Union (AGU) sponsored a Chapman Conference on Hydrogeochemical Responses of Forested Catchments. Approximately 130 hydrologists, geochemists, soil scientists, ecologists, and other scientists involved in research on forested catchments presented results of their investigations and discussed the state of knowledge regarding hydrological and geochemical processes that control catchment response.

Within the field of catchment hydrogeochemistry, the focus of geochemists has been to attain an understanding of the basic processes which govern the interactions between water and rocks, whereas the focus of hydrologists has been to determine rates of flow along different flow paths through a catchment. Of course, geochemists are well aware that the explanation of temporal variation of the chemical composition of surface and ground waters requires knowledge of flow paths and residence times of water as well as of chemical processes per se, and hydrologists know that flow generation mechanisms can be identified most efficiently in the field by using information about the geochemical history of waters. Nevertheless, cross-discipline communication has not been as pervasive as desirable for rapid advancement of the science. The Chapman Conference, organized by two of us (M. Robbins Church and George M. Hornberger), brought hydrologists and geochemists together to discuss recent significant contributions with the hope that progress in the future would be speeded up by the interdisciplinary information exchange.