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Impacts of natural and human drivers on the multi-decadal morphological evolution of tidally-influenced deltas

Impacts of natural and human drivers on the multi-decadal morphological evolution of tidally-influenced deltas
Impacts of natural and human drivers on the multi-decadal morphological evolution of tidally-influenced deltas
The world's deltas are at risk of being drowned due to rising relative sea levels as a result of climate change, decreasing supplies of fluvial sediment, and human responses to these changes. This paper analyses how delta morphology evolves over multi-decadal timescales under environmental change using a process-based model. Model simulations over 10^2 years are used to explore the influence of three key classes of environmental change, both individually and in combination: (i) varying combinations of fluvial water and sediment discharges; (ii) varying rates of relative sea-level rise; and (iii) selected human interventions within the delta, comprising polder-dykes and cross-dams. The results indicate that tidal asymmetry and rate of sediment supply together affect residual flows and delta morphodynamics (indicated by sub-aerial delta area, rates of progradation and aggradation). When individual drivers of change act in combination, delta building processes such as the distribution of sediment flux, aggradation, and progradation are disrupted by the presence of isolated polder-dykes or cross-dams. This suggests that such interventions, unless undertaken at a very large scale, can lead to unsustainable delta building processes. Our findings can inform management choices in real-world tidally-influenced deltas, while the methodology can provide insights into other dynamic morphological systems.
1364-5021
1-26
Angamuthu, Balaji
738c5cb9-9c4c-42b9-acdc-240e3ff80dba
Darby, Stephen
4c3e1c76-d404-4ff3-86f8-84e42fbb7970
Nicholls, Robert
4ce1e355-cc5d-4702-8124-820932c57076
Angamuthu, Balaji
738c5cb9-9c4c-42b9-acdc-240e3ff80dba
Darby, Stephen
4c3e1c76-d404-4ff3-86f8-84e42fbb7970
Nicholls, Robert
4ce1e355-cc5d-4702-8124-820932c57076

Angamuthu, Balaji, Darby, Stephen and Nicholls, Robert (2018) Impacts of natural and human drivers on the multi-decadal morphological evolution of tidally-influenced deltas. Proceedings of the Royal Society A, 474 (2219), 1-26. (doi:10.1098/rspa.2018.0396).

Record type: Article

Abstract

The world's deltas are at risk of being drowned due to rising relative sea levels as a result of climate change, decreasing supplies of fluvial sediment, and human responses to these changes. This paper analyses how delta morphology evolves over multi-decadal timescales under environmental change using a process-based model. Model simulations over 10^2 years are used to explore the influence of three key classes of environmental change, both individually and in combination: (i) varying combinations of fluvial water and sediment discharges; (ii) varying rates of relative sea-level rise; and (iii) selected human interventions within the delta, comprising polder-dykes and cross-dams. The results indicate that tidal asymmetry and rate of sediment supply together affect residual flows and delta morphodynamics (indicated by sub-aerial delta area, rates of progradation and aggradation). When individual drivers of change act in combination, delta building processes such as the distribution of sediment flux, aggradation, and progradation are disrupted by the presence of isolated polder-dykes or cross-dams. This suggests that such interventions, unless undertaken at a very large scale, can lead to unsustainable delta building processes. Our findings can inform management choices in real-world tidally-influenced deltas, while the methodology can provide insights into other dynamic morphological systems.

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More information

Accepted/In Press date: 1 October 2018
e-pub ahead of print date: 7 November 2018
Published date: November 2018

Identifiers

Local EPrints ID: 426081
URI: https://eprints.soton.ac.uk/id/eprint/426081
ISSN: 1364-5021
PURE UUID: aef202ee-4afa-4d22-9aee-8647f6d4d98f
ORCID for Stephen Darby: ORCID iD orcid.org/0000-0001-8778-4394
ORCID for Robert Nicholls: ORCID iD orcid.org/0000-0002-9715-1109

Catalogue record

Date deposited: 13 Nov 2018 17:30
Last modified: 14 Mar 2019 01:49

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