Shoreline Changes at Llangennith Burrows – Part 1

When there are especially dramatic events, like the severe winds and storms of last January and February, that destroyed coastal railway lines, caused major landslips, created disastrous flooding, and removed entire beaches of shingle and sand, everyone becomes aware of how vulnerable our coastline is to extreme weather events. However, visiting the same seashore locations many times over the past ten years, and making a detailed photographic record of animals, plants, sediments and rocks, has enabled me to see changes gradually and steadily taking place as well as resulting from these recent extreme events.

This is the first in a series of posts about changes in shoreline topography, sometimes due to accretion of sediments, sometimes resulting from erosion, that have been changing the way the seashore looks. These changes have an impact on the whole coastal ecosystem, affecting plant communities, the invertebrates that colonise the seashore, and the people who use and enjoy the shorelines.

I have been trying to find among the many images in my collection, those which show recognisably the same place, to illustrate what the location looked like originally, some of the details of the transition if any, and what the location looks like now. In this post, the location is the seaward-facing sand dunes belonging to Llangennith Burrows, at the north end of Rhossili Beach, approaching the tidal island of Burry Holms. The position is “fixed” by a vertical wooden sign indicating one of the designated footpaths that cross the Burrows.

In the first photograph, shown above, the wooden post has had some bright orange plastic flotsam tied to it with rope, to increase its visibilty from low on the sandy beach. The picture was taken on the 16th May 2012. Wind-blown dry sand forms a continuous and gradual incline from the shore to the top of the dune. The dune is stabilised by marram grass. Pebbles at the base of the dune are only just visible beneath the layer of sand. The footpath passes to the right of the signpost, forming a shallow depression on the sky-line.

The image immediately below shows the same location two years later on 6th May 2014. The signpost lacks the orange flotsam now but the footpath can still be seen to the right of it, forming a steep gouge in what remains of the dune. The seaward face of the dunes has been reduced in places to a near vertical surface showing stratification of the established dune. Mobile sand deposits are almost entirely absent. Much of the marram grass has fallen down as turf clumps or disappeared. Pebbles are clearly exposed at the base of the dunes.

Of course, the changes started long before May 2012. The sea has been nibbling at the compacted sand of the dunes for a while, and in between times, the loose sand moves in, out, and all around the beach, sometimes from day to day, and even from tide to tide. However, the hard stratified sand in the dunes has been steadily and inexorably receding. The following pictures show in a bit closer detail what the same area of the Llangennith/Rhossili dunes was looking like at one point (12th December 2012) in the interim period between the times that photographs 1 & 2, and 3 & 4  were taken.

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