Long-term coastal dynamics: The evolution of a mixed sediment mega-nourishment consisting of colliery spoil.

Autor: Pitman SJ; School of Geography Politics and Sociology, Newcastle University, Newcastle Upon Tyne, UK. Electronic address: seb.pitman@ncl.ac.uk., Burke IT; School of Earth and Environment, University of Leeds, Leeds, UK., Jay H; National Trust, Swindon, UK., Cooper N; HaskoningDHV UK Ltd, Newcastle Upon Tyne, UK., Mayes WM; School of Environmental Sciences, University of Hull, Hull, UK., Jarvis AP; School of Engineering, Newcastle University, Newcastle Upon Tyne, UK.
Jazyk: angličtina
Zdroj: Journal of environmental management [J Environ Manage] 2024 Oct 31; Vol. 371, pp. 123106. Date of Electronic Publication: 2024 Oct 31.
DOI: 10.1016/j.jenvman.2024.123106
Abstrakt: Mega-nourishments, where large volumes of sediment are deposited on coastlines, are increasingly employed to manage shoreline erosion, yet our understanding of their long-term behaviour is limited by the fact that most current schemes are less than 15 years old. However, on the County Durham coast, 39 million m 3 of coal spoil was tipped onto beaches between the late 1800s and 1993, acting as a de facto mixed sediment mega-nourishment. Our findings reveal key insights into the long-term dynamics of mega-nourishment schemes, including evidence of effective sediment dispersal around headlands into normally disconnected units of coast. Following cessation of tipping, shorelines retreated up to 12 m yr -1 , with 150 m overall retreat in 12 years. Subsequently, retreat slowed but the present-day shoreline remains seaward of its 1860 position and is subject to ongoing coastal recession. We document significant fining of the deposited material in the years post deposition through abrasion and chemical breakdown. Furthermore, we show that the highest erosion rates now occur downdrift from the initial dump site, indicating that nourishment impacts migrate through time. These findings highlight the need for holistic and adaptive management approaches to mega-nourishment schemes, showing the behaviour of the nourishment to continually change in both location and magnitude as the system evolves. We demonstrate that mixed sediment mega-nourishments can be a cost-effective and durable solution to mitigate erosive losses, even in the absence of a planned approach to the location or composition of deposited sediment. Our results suggest that lessons from this historical intervention can inform the design and management of future mega-nourishment schemes, particularly in mixed sediment environments.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:S Pitman reports financial support was provided by UK Research and InnovationNatural Environment Research Council. A Jarvis reports financial support was provided by UK Research and InnovationNatural Environment Research Council. I Burke reports financial support was provided by UK Research and InnovationNatural Environment Research Council. W Mayes reports financial support was provided by UK Research and InnovationNatural Environment Research Council. S Pitman reports financial support was provided by British Society For Geomorphology. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
Databáze: MEDLINE
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