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

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.

+ Between 2005 and 2015 the UK government spent about £6 billion on flood and coastal erosion risk management, with the annual figure (most recently £795 million) having risen sharply over the last two years (about 62% of this is coastal flooding or erosion, according to previous estimates). The work proposed will result in a better understanding of coastal morphodynamics, around the UK coast in particular, and so the UK government will benefit in terms of better designed, more predictable, less invasive coastal defences. This will also save money in the future.
+ District councils, and all other bodies who manage the coastal environment will similarly benefit.
+ Coastal engineering consultants and contractors will benefit from more reliable numerical models, and a better understanding of these dynamics, so that traditional model output can also be assessed from a more knowledgeable perspective. Modelling may also be carried out faster using the amplitude equation approach.
+ The improved statistical model will also mean that coastal change can be assigned more reliable error estimates, thus reducing uncertainty. This will again help coastal managers, but also the insurance industry in producing better estimates of risk for homes / businesses at risk of flooding, thus reducing costs across the board.
+ In the future, tourists will benefit from fewer beaches being rendered unusable or unsightly, because the proposed coastal defence strategies involve longer-term solutions without recourse to hard engineering structures. This will similarly benefit local economies.