A Review of Erosional Processes along a River Continuum: Watershed-scale Implications for River Restoration Planning

Management of sediment within watersheds disturbed by human activates is vital for the biological protection of our nation's waterways. Excessive fine sediment in rivers and streams is the most cited cause for water quality impairment in most states, leading to the development of total maximum daily loads (TMDLs) for 303d listed waterbodies. Understanding the potential sources of fine sediment generated by erosion processes that change from headwater areas to lower river reaches is important in the development of effective watershed management strategies. These strategies need to regulate sediment transport within natural ranges that support native lotic biota. Reviews of the erosion processes from field-scale overland (sheet) flow, shallow concentrated flow, first-order gully and headcuts, and stream channel bed and bank were examined, and differences defined. Recognizing the process differences and the potential sediment yields per watershed location provides a mean to assess whether restoration efforts are best implemented. Overall, this paper summarizes different erosional processes along a river continuum, describes how scale can skew sediment yield estimation, and elaborates on how scale can alter which best management practices are used.