Science Base and Tools for Evaluating Stream Engineering, Management, and Restoration Proposals

摘要

Management actions within stream corridors span a wide range of intended outcomes, including reconstruction or renovation of structural assets, channel rehabilitation, stabilization of eroding streambanks, management or diversion of in-channel and overbank flows, sediment management, river restoration, and habitat enhancement to promote a single species or overall biodiversity. Because streams are complex and dynamic systems, projects undertaken with the best of intentions still cause unintended outcomes that often pose risks to fisheries or habitat, either directly or through introducing additional constraints on natural processes. In this source document, we begin by providing the tools for the evaluation of project proposals. Next we present a synthesis of the science of fluvial geomorphology as it relates to river system habitat, beginning with watershed controls and progressing to the specifics of stream channel morphology. This synthesis provides a thorough scientific foundation for evaluating the consequences of stream projects, with emphasis on their potential impact to physical processes and associated habitat. Finally, we present a logical process for developing stream management projects, including those restoration and stabilization projects intended to improve habitat. Together, the tools and document provide an efficient, scientifically based method for evaluating proposed stream management projects with respect to their potential risks to species and habitat.