The Northern River Basins Study (NRBS) assessed the ecologicalstate of three complex northern river basins for which we had a limitedunderstanding of the physical, chemical and biological environment. Amajor challenge of this study was the choice of ecosystem components tomonitor. This process was guided by determining the indicators thatwould best assess environmental state relative to ecosystem objectivesarticulated by people living within the basin. This charge lead the NRBSto use a cumulative effects assessment framework that measured stressorexposure and their effects along with the development of plausiblecause-effect mechanisms. Thus, the NRBS developed and applied anintegrated assessment framework that included public stakeholders,various levels of government and scientists. A key feature of thisframework was the ability to allow feedback among these groups toproduce the syntheses of science results, and the resultant managementresponses that ultimately modified environmental regulations. Papers inthis series present the results of the NRBS and emphasize theinterdisciplinary nature of this project. Investigations evaluated theroles of flow regulation, nutrients, contaminants, and their interactiveeffects, on the integrity of the Athabasca, Peace and Slave rivers,Canada. Novel contributions of the NRBS model included the cooperationamong governments, aboriginal peoples, non-government organizations,industry and other stakeholders, and the two-way communications flowamong the scientific community and these groups.