MORPHINE: Re-designing the coast: The Morphodynamics of Large Bodies of Sediment in a Macro-tidal Environment

Lead Research Organisation: Swansea University
Department Name: School of Engineering

Abstract

We propose developing the mathematical theory of morphodynamics as it pertains to a macro-tidal environment (coastal region with large tidal range, like that in the UK), so as to understand the movement of large deposits of sand on our beaches and shorefaces (shorefaces are, loosely, the regions in between the beach and the continental shelf floor). This theory will allow us to formulate a new mathematical modelling approach. New models stemming from this will allow us to develop a new approach to designing sea defences, in which large quantities of sand ("nourishments") are deposited at strategic locations at and / or near to the coastline. These nourishments will provide a source of sediment for beaches that are eroding, but, importantly, they will also alter local wave and current conditions, which will transform previously eroding beaches into more stable configurations, and so form naturalistic coastal defences.
The theory and the models, coupled with a new, realistic statistical model of sea conditions, will make it possible for us to predict the behaviour of these nourishments to a high degree of accuracy under different conditions. Because the models are highly efficient we will be able to do this for long times (say, 20 years or more), and to investigate the likely variations in wave conditions that might occur during this time. This will support the design of this new approach to designing sea defences, and will mean that we do not have to rely on invasive, expensive and reactive traditional sea defences. It will have the additional benefit of providing the means to predict how a major proportion of our existing coast will behave in the future. The proposal addresses UK conditions in particular, in which a very large tidal range combines with a wide variety of wave conditions to produce a particularly challenging environment. We are therefore proposing to undertake fundamental work on coastal morphodynamics so as to develop tools that will let us re-think our coastal defence strategy.

Publications

10 25 50
 
Description Proof of concept for creating wave sequences (height, period and direction) with identical statistical characteristics as a reference sequence. We have shown that an auto-regressive technique can be used to recreate the marginal distributions and the auto and cross-correlation properties inherent in wave conditions.
Analytical beach modelling methods have been combined with measurements of large scale coastal changes at two sites: one in India and one in Texas, USA. Results show that except for the wave-induced littoral drift, other unspecified factors can affect significantly and in an unpredictable way the large scale beach morphodynamic evolution. The analytical model has been adjusted to incorporate the effect of sources or sinks of sediment material, (i.e. mega nourishment or sand removal), to simulate changes in the morphodynamic evolution which cannot be explained though the longshore sediment transport caused by wave action.
Exploitation Route The concept could be applied to Monte Carlo modelling in a wide range of field that require correlated variables as inputs.
The large scale beach modelling is in the process of development and initial results are to be presented to a mixed academic/practitioner audience at Coastal Sediments 2019 in Tampa in May 2019.
Sectors Aerospace, Defence and Marine,Construction,Education,Energy,Environment

 
Description Professors Dodd and Reeve provided brief technical advice to the Royal HaskoningDHV team responsible for the Bacton sandscaping project regarding the sediment composition of proposed sand nourishment and the limitations of current modelling tools.
First Year Of Impact 2017
Sector Construction,Energy,Environment
Impact Types Societal,Economic

 
Description ITB - ICMSE Lecture 
Organisation Bandung Institute of Technology
Country Indonesia 
Sector Academic/University 
PI Contribution In October 2018 I visited Dr Magdalena (Department of Mathematics, Institut Teknologi Bandung, Indonesia), to give an invited lecture on 'Applying mathematics to the problem of coastal protection', as part of the 5th International Conference on Mathematics, Science and Education (ICMSE), Universitas Negeri Semarang, Bali, Indonesia. The work we are undertaking as part of the MORPHINE project formed an integral part of the talk.
Collaborator Contribution The extended an Speaker invitation to me and hosted my visit.
Impact One student from ITB had a 2 week visit to Swansea to undertake some experiments in our wave tank. Two papers, coauthored with Dr Magdalena and her students, are now in preparation.
Start Year 2018
 
Description Royal HaskoningDHV - beach sandscaping 
Organisation Royal HaskoningDHV
Country Netherlands 
Sector Private 
PI Contribution On Aug 21st, 2018 Prof Dodd and Prof Reeve met with a senior representative of Royal Haskong DHV at the University of Nottingham to discuss possible implementations of sandscaping solutions at various representative locations (i.e. scenarios). Discussions included the kinds of possible implementations, and the stability concept.
Collaborator Contribution We provided technical advice relating to sandscaping at Bacton.
Impact none to date
Start Year 2017