Enhancing Resilience of River Restoration Design in Systems Undergoing Change

Abstract

Landscape-scale changes in hydrology, sediment dynamics, and riverine ecosystems are raising questions about how resilience to changing conditions should be integrated in the design of river restoration projects. This study synthesized current strategies and challenges for river restoration in systems governed by change, emphasizing (1) an international survey of practitioners to document the state-of-the-practice, including challenges facing practitioners implementing river restoration and (2) a literature review of the state of the art in designing for resiliency, including advantages and limitations of established and more-experimental design approaches and tools. Survey results highlighted fundamental challenges associated with identifying appropriate project objectives within a design practice largely relying on historical data, the significance of social and regulatory barriers, and the need to focus on underlying processes. Important discrepancies between the expectations for resiliency of projects and the practices being implemented emerged. The state-of-the-art literature review summarized how design strategies may be modified to address those discrepancies, and discussed the divergent approaches for increasing resilience through (1) increasing resistance to change (i.e., stabilization) and (2) restoration of a channel’s dynamism to reduce the risk of, and recovery time following, disturbances. Both the state of the practice and the state of the art highlight the lack of resiliency within the practice of river restoration itself, and illustrate the importance of designers, funders, regulators, and stakeholders adapting and innovating as the natural and human landscape they are managing changes.