Why Consider Geomorphology in River Rehabilitation?

A philosophical and communication shift is needed in river management if we are to meet sustainable development goals and tackle environmental challenges brought about by ongoing anthropogenic and climate change. In some parts of the world, recovery‐enhancement approaches to river management have been adopted, communicated and used for many years. At the heart of these approaches lies an understanding of the biogeomorphic forms, processes and evolutionary trajectories of rivers that differs philosophically from notions of restoration, rewilding or creation of a utopian natural state. Instead, recovery‐enhancement approaches aim to improve the biogeomorphic condition of rivers, recognising that they are dynamic entities and new evolutionary trajectories and novel ecosystems are being created that are now part of the environment. Accepting shifting baselines and moving targets is inherent as boundary conditions (water, sediment and vegetation interactions) continue to be altered under the influence of anthropogenic and climate change, and the impacts of ‘unprecedented’ wildfires, floods, heatwaves and drought are manifested on the ground. The river management sector has not yet fully adapted to this reality with large amounts of applied science and on‐ground practice still focussed on restoration, re‐engineering and rewilding, words which in themselves produce a false impression of the aims, visions and achievability of river management. Embracing recovery‐enhancement approaches to river management requires a conscious shift in communication strategies and terminology to present more realistic expectations and possibilities for river condition improvement, a responsibility that is incumbent upon us, the scientists and practitioners, who work in the applied science and river management profession. In this Short Communication, I use a case study from eastern Australia to illustrate what biogeomorphic river recovery can look like. I use this to discuss the potential for adoption of a recovery‐enhancement approach to river management more broadly, and call on scientists and practitioners to make a conscious philosophical and communications shift when working in applied science and river management.

Section: Discussionmentioning

confidence: 99%

Leveraging understandings of biogeomorphic river recovery to reframe river management philosophy and communication strategies

Fryirs

2024

“…Our primary objective in this paper is to discuss the importance of geomorphic context in conceptualizing and implementing processbased restoration. Others have addressed this issue (e.g., Fryirs & Brierley, 2009;Nakamura et al, 2017;Piégay et al, 2023) and we build on their work by explicitly tying geomorphic context to the prioritization of restoration methods and site selection. We first expand on the idea of context by considering river corridor function as created by fluxes within a geomorphic context, then discuss anthropogenic alterations and associated legacy effects that influence the geomorphic context of rivers.…”

mentioning

confidence: 99%

Geomorphic context in process‐based river restoration

Wohl,

Rathburn,

Dunn

et al. 2024

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.

Societal drivers for the integration of hydrogeomorphology and human benefits in river restoration projects

Gariépy‐Girouard,

Buffin‐Bélanger,

Biron

2024

Integrating hydrogeomorphological (HGM) principles into the restoration of degraded rivers can achieve sustainable results and provide various human benefits. HGM principles mainly involve understanding the context and processes that shape a fluvial system before any intervention, in order to support its dynamism and to align with its potential functioning and uses. Despite recent management approaches inspired by HGM principles, most restoration projects carried out in Quebec (Canada) are not process‐based and target specific one‐dimensional objectives. Although there is an overall lack of post‐project monitoring, several projects appear to have failed or had mixed success. This research aims to shed light on the diversity of societal drivers behind river restoration projects and to examine how they influence the integration of HGM principles and human benefits. Four restoration projects were characterized through participant observation and interviews with the organizations running them. Representatives of two ministries involved in river restoration and management were also interviewed. The results show that projects were mainly shaped by public acceptance disregarding HGM principles, which can lead to poorly‐informed action. Project funding and stakeholders' expertise have also challenged project implementation and played a key role in defining their objectives. The addition of these components improve the current analytical frameworks for identifying river restoration objectives. Depending on specific sociocultural, political and legislative contexts, funding programs and stakeholders' expertise may either facilitate or restrict the integration of HGM principles and human benefits in the projects. Recognizing these key drivers reframes river restoration as a fundamentally social activity and enlightens how they could impel innovative approaches towards more sustainable results.