The River Continuum Concept proposes that natural stream ecosystems may be characterized as extending continuosly from their headwater beginnings to their mouth or estuary. Furthermore, this continuous stream system provides a gradient of changing physical, chemical, and biological conditions.(Windell, 1992) The river continuum concept is widely used to understand ecological changes along the length of a river and predict the way that biological communities might change. It provides a model of changes that might take place as water travels from headwater streams to large rivers.