Riverine large wood and recreation safety: A framework to discretize and contextualize hazard

摘要

The importance of large wood (LW) to riverine functions is well established scientifically and increasingly recognized by river managers in many countries. However, public perceptions largely associate LW with elevated danger and/or need for intervention. Such perspectives are amplified amongst recreational river users (defined here as any individuals that recreate by floating on the water surface of a river) who interact more directly with rivers than the general public and commonly view wood in life-or-death terms. Given that human life occupies a highest-order charge for river managers, they are left in a difficult position when safety appears to conflict with environmental services. LW deficits are perpetuated partly because wood removal, often in the name of safety, is far easier than placing wood in rivers. Further, river restoration practitioners are frequently burdened with expectations and liability unparalleled in built environments. A fundamentally different mindset is necessary to achieve desired ecologic outcomes when working with rivers. Based on two decades of experience as boaters, LW practitioners, and emergency responders, we (1) discuss LW hazard and risk from recreational and management viewpoints, (2) discretize objective and measurable physical properties of LW hazards, and (3) propose a decision framework that implicitly addresses risk by considering LW hazards relative to river use and ambient hazards. The approach is structured to increase objectivity in LW hazard mitigation and diminish asymmetric biases that favor LW removal. Our intent is to build understanding and rational flexibility among risk-averse management, regulatory, and funding entities to facilitate implementation of scientific understanding without undue risk to river users. (c) 2020 John Wiley & Sons, Ltd.