Restoring form and processes in Urban streams: The state-of-the-art

Stream restoration and channel design projects are often based on morphological form or stream type, and as a result there needs to a clear tie established between form and function of the stream. A state-of-the-art examination of the literature will identify numerous relationships in naturally forming streams that link morphologic form and stream processes. Due to infrastructure constraints, design protection hard-points, and highly altered hydrologic and sediment discharge regimes, channel processes and the resulting channel forms and patterns that are observed in urban streams will differ significantly from those observed in naturally adjusting streams. As a result, the design and construction of channel projects in the urban setting is fraught with uncertainty. In this paper, we examine existing relationships between form and processes, the strengths and weaknesses of existing relationships, and the uncertainty in applying these relationships to stream restoration designs in the urban environment.