The Effects of Flow Regime and Land Use Practices on Ecological Health in the Grand Ronde Sub-basin

Ann D. Fissekis

The River Continuum Concept (Vannote et al. 1980) was developed to provide an accurate description of the downstream trends of biologic communities in response to changing physical systems. However, while the RCC claims to accommodate land use perturbations of physical factors such as flow regime, research indicates that land use impacts depend on both type of industry and location along the river channel. Furthermore, no definitive relationship is established for the effects of land use in large basins. While the Grande Ronde’s flow regime has changed in a way that is consistent with the expected impacts of its land use practices on the magnitude and timing of flows, more specific knowledge that quantifies the relationship between industry and flow regime is needed to make the RCC a more accurate tool.