In this organized oral session, rising and established aquatic biologists and river conservationists will assemble to discuss factors that contribute to successful aquatic biodiversity conservation in the face of often intense pressure to exceed flow limits that must be set to maintain biodiversity in lotic systems. Session participants from many latitudes will explore how recent advances in basic ecological research can offer solutions to key technical sticking points in determining requirements for environmental flows in fluvial systems. Participants also will describe how the need for improved technical solutions has yielded new avenues of inquiry in basic ecology research. Specific topics will include the decision tools necessary for recommending minimum flow requirements, parameters necessary for replication of natural flow periodicity, minimum flow requirements for successful maintenance of floodplain habitats, effects of flow alteration on fish populations, nutrient cycling, and river physico-chemical parameters, and the fundamental similarities and differences between temperate and tropical flow regimes.