COMEM student Charles Feys reports on Dr Eli Lazarus’ coastal seminar

The coastal seminar series in the winter semester of 2017 was kicked off by the enthusiastic Dr. Eli Lazarus, who gave his presentation the intriguing name “Weird Dynamical Signatures from Developed Coastlines”. As a recent addition to the University of Southampton staff, he brought an interesting perspective on the sediment problems on the East Coast of the United States. He started by quoting from the book ‘Disasters by design’ by Dennis S. Mileti: “We know and understand more about natural disasters now than ever before … but the cost of disaster events keeps going up.” This because research into erosion and coastal storms is and should be a very active research.

We learned that not only nature is to blame for the problem. If people would not construct houses, resorts, beaches, etc., the problem would be way smaller, if not inexistent. However, this is not the case. Coastlines have been heavily built, close to saturation in some cases, with extra sea defences to cope with Sea Level Rise (SLR) included. But there is no way to stop erosion from beaches altogether, and where an erosion problem is believed to have stopped, there is still something such as ‘masked erosion’. Investigating the long-term shoreline change rates on the East Coast of the USA, it can be seen that before 1960, there was a mean coastline retreat rate of 55 cm/year, but after 1960 a coastline seaward advance of 5 cm/year can be seen. This rises many questions.

One explanation of this strange phenomenon is beach nourishments and the link between coastal development and nourishments. As mentioned before, coastal erosion and storms can be considered only a problem where the coast is developed, so looking at a possible link between coastal structures and beach nourishments can help sketch the severity of damages of possible storms. Now zooming in onto the coasts of the state Florida; a lmost everywhere, the coasts have been heavily nourished over the years. Everything from house sizes, house areas and the number of houses seems to be larger at sites where the beach had been artificially nourished, than where the beach was left to go its natural way.

The third and final part of the presentation was called ‘Dukes of Moral Hazard’. Here, a strange phenomenon is noted, that could pose some moral questions. Much of the East Coast is very vulnerable to hurricanes and sadly in some past events, much of the buildings and infrastructure has been destroyed by natural events. And one of the answers of the people was to … build their houses back bigger in hurricane strike zones. And here, the beginning of the presentation is refreshed: ‘Disasters by design’ by Dennis S. Mileti. Is the reason the cost of damage is getting up because of climate change? Partly yes, but the problem is also a human one. Larger properties at the coast are potentially bigger damages by storm events.

If this has peaked your interest, the following literature is suggested:

Armstrong, S., Lazarus, E., Limber, P. W., Goldstein, E. B., Thorpe, C., & Ballinger, R. C. (2016). Indications of a positive feedback between coastal development and beach nourishment. Earth’s Future, 4(12), 626-635, doi: 10.1002/2016EF000425

Davis, J. L., and N. T. Vinogradova (2017), Causes of accelerating sea level on the East Coast of North America, Geophys. Res. Lett., 44, 5133–5141, doi:10.1002/2017GL072845.

Lubchenco, J. and Karl, T. (2012) Predicting and managing extreme weather events. Physics Today, 65, 31-37. doi:10.1063/PT.3.1475

Mileti, D. (1999) Disasters by Design: A Reassessment of Natural Hazards in the United States. Joseph Henry Press.

 

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