Long-term geomorphic adjustments following the recoupling of a tributary to its main-stem river

dc.contributor.authorBlackburn, Joel
dc.contributor.authorMarteau, Baptiste
dc.contributor.authorVericat Querol, Damià
dc.contributor.authorBatalla, Ramon J.
dc.contributor.authorComte, Jean-Christophe
dc.contributor.authorGibbins, Christopher
dc.date.accessioned2023-01-23T09:33:24Z
dc.date.available2023-01-23T09:33:24Z
dc.date.issued2023
dc.description.abstractRiver restoration and rehabilitation projects are widespread, but rarely include the data needed to fully evaluate if they are successful in achieving their goals or how long the process of readjustment takes before a new ‘recovered’ regime state is reached. Here we present a seven-year post-project dataset detailing the morpho-sedimentary responses of a river to the reconnection of a formerly diverted tributary, and relate observed changes to conditions in the river prior to the reconnection. We describe changes in the tributary and main-stem channels, including changes in channel planform, morphology, and the export of coarse and fine sediment from the tributary to the main-stem river. We use the data to develop a conceptual model of the system's response to the reconnection. Marked geomorphic changes occurred within the first two years after the reconnection. Changes during this ‘shock phase’ included dramatic erosion and subsequent deepening and widening of the tributary channel, rapid development of a confluence bar and an increase in fine sediment delivered to the main-stem. After this shock phase, and despite the continued occurrence of high magnitude flow events, the rate of geomorphic change in the tributary began to decrease, and the rate of growth of the confluence bar slowed. Fine sediment volumes in the main-stem also decreased steadily. After an adjustment phase lasting a total of approximately 4.5 yr (including the initial 2-yr shock phase), the tributary to mainstem system appeared to reach a new dynamic equilibrium that we consider the adjusted regime state. This new regime state was characterised by, among other things, an increase in geomorphic heterogeneity in the tributary and main-stem channels. Changes in both fluvial processes and forms indicate that within 4.5 yr the project was successful in achieving its goal of augmenting sediment and increasing geomorphic heterogeneity. Our conceptual model of adjustment mirrors that developed by Petts and Gurnell (2005), with the river passing through a complex and dynamic adjustment phase before reaching a new regime state. However, unlike the responses to impoundment represented by Petts and Gurnell, our model of river response to rehabilitation charts increases in dynamism and heterogeneity.ca_ES
dc.description.sponsorshipThe research presented in this paper has been supported by a number of organisations. We thank United Utilities (UU) and the Environment Agency (EA) for funding and support. In particular, we thank Kat Liney and Alice Senior from UU, and Gez Foster and Jane Atkins from EA. Part of this research benefited from the methods and outcomes of the MorphHab (PID2019-104979RB-I00/AEI/10.13039/501100011033) research project. B. Marteau's contribution was in part supported by a postdoctoral fellowship from the EUR H2O'Lyon (ANR-17-EURE-0018). D. Vericat is a Serra Húnter Fellow at the University of Lleida. We are also grateful to the reviewers and editor for their comments that improved the manuscript.ca_ES
dc.identifier.doihttps://doi.org/10.1016/j.geomorph.2022.108561
dc.identifier.issn0169-555X
dc.identifier.urihttp://hdl.handle.net/10459.1/85290
dc.language.isoengca_ES
dc.publisherElsevierca_ES
dc.relationinfo:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2019-104979RB-I00/ES/LA IMPORTANCIA DE LA DINAMICA MORFO-SEDIMENTARIA EN LA CARACTERIZACION Y EVALUACION DEL HABITAT FISICO FLUVIAL. IMPLICACIONES PARA LA GESTION EFICIENTE Y PERDURABLE DE RIOS/ca_ES
dc.relation.isformatofReproducció del document publicat a https://doi.org/10.1016/j.geomorph.2022.108561ca_ES
dc.relation.ispartofGeomorphology, 2023, vol. 424, núm. 108561, p. 1-13ca_ES
dc.relation.projectIDANR-17-EURE-0018ca_ES
dc.rightscc-by (c) Blackburn et al., 2023ca_ES
dc.rights.accessRightsinfo:eu-repo/semantics/openAccessca_ES
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/*
dc.subjectGeomorphic adjustmentca_ES
dc.subjectLong-term monitoringca_ES
dc.subjectRiver restorationca_ES
dc.subjectTributary reconnectionca_ES
dc.subject.otherGeomorfologiaca_ES
dc.subject.otherEnginyeria fluvialca_ES
dc.titleLong-term geomorphic adjustments following the recoupling of a tributary to its main-stem riverca_ES
dc.typeinfo:eu-repo/semantics/articleca_ES
dc.type.versioninfo:eu-repo/semantics/publishedVersionca_ES
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