Geomorphic context in process‐based river restoration

Abstract

Process‐based river restoration seeks to restore processes such as channel‐floodplain connectivity that create and maintain river corridor functions. Process‐based restoration can fail to produce the desired results if geomorphic context is not effectively incorporated into restoration design. Geomorphic context of a river reach refers to the controls on contemporary river form and process. Controls at the catchment‐ to reach‐scale include geologic history, biophysical characteristics, legacies of past human alterations, position within the river network, river corridor geometry, base level stability, disturbance regime, and contemporary human alterations of the river corridor. We conceptualize a river corridor as reflecting the interactions among fluxes of material and the geomorphic context. We discuss how an understanding of geomorphic context can be used to select a restoration approach and provide examples of how restoration can fail to achieve desired outcomes when geomorphic context is not considered. Within the toolbox of methods used to implement process‐based restoration, we differentiate the alteration of inputs to the river corridor and fluxes of material through the corridor from alteration of form and/or connectivity within the river corridor. Historical, biotic, geologic/geomorphic, and reference sites can be used to inform process‐based restoration targets. Restoration is strongly influenced by human perceptions of what is appropriate and achievable at a site and diverse communities influencing restoration at a site may differ in their perceptions. Geomorphically based conceptual guidelines, such as the River Styles Framework, provide an effective platform for incorporating an understanding of geomorphic context into process‐based river restoration.

An Analysis of Society’s Willingness to Restore the Aquatic Environment in Romania

“…As opposed to other studies in the field that analyzed the spatial connectivity method in certain communities, this study obtains information from the final beneficiaries of the connectivity reestablishment measures [39,49,50,52]. The decision-making authorities in the field do not have a relevant and accurate methodology, as no study has been conducted regarding reestablishing longitudinal connectivity.…”

“…Community perception analysis can add to research on the impact of barriers that are built on rivers and on the connectivity of a river network [11,65], and it can complement a range of methodologies for analyzing the territorial context, such as fractal analysis or spatial modeling, the relevance of which are highlighted in numerous studies [66][67][68][69][70][71][72][73][74][75]. Also, perceptions of longitudinal connectivity provide relevant information on the ecological quality of river sections [39,75,76].…”

“…This survey indicates that people would normally allocate more money to increasing the quality of the aquatic environment in general and less to specific one-off actions such as fish ladders (fish ways), which in themselves increase biodiversity and, therefore, the Community perception analysis can add to research on the impact of barriers that are built on rivers and on the connectivity of a river network [11,65], and it can complement a range of methodologies for analyzing the territorial context, such as fractal analysis or spatial modeling, the relevance of which are highlighted in numerous studies [66][67][68][69][70][71][72][73][74][75]. Also, perceptions of longitudinal connectivity provide relevant information on the ecological quality of river sections [39,75,76].…”

“…The watershed has been transformed over time into an urban, industrial or agricultural production center, and less consideration has been given to its potential valorization as an asset to local communities [37][38][39].…”

The ecohydrology of rewilding: A pressing need for evidence in the restoration of upland Atlantic salmon streams

“…How "restoration" at the reach scale can equilibrate with residual catchment-scale controls remains an open question. Ignoring this geomorphic context and lack of knowledge of response times to change has the potential to undermine the sustainability of many restoration schemes and cause unexpected problems, including negative impacts(Wohl et al, 2023(Wohl et al, , 2024. Many restoration techniques are still largely untested with unclear or poorly established benefits, ill-defined risks and uncertain outcomes.…”