22 November 2013
The best way to prevent flooding or erosion of coastal lands by the sea is to maintain a healthy beach between the two. A beach is a natural absorber of wave energy and without a beach waves would hit the sea walls behind with explosive force, like they do on the Brighton Marina walls. The shingle on the beach absorbs wave energy by moving when the waves hit, just like with shock absorbers on a car’s suspension or the mattress on a bed when you jump onto it.
However, because most of our waves come from the south west, they slowly move the shingle on the beach eastwards and locally it all ends up stacking up against our western harbour arm and Brighton Marina. This is a process called littoral drift and in order to enable the beaches to keep on working (and the Port operational!) we have to move the shingle so that no length of seafront is left without a beach.
Tony Parker, Director of Engineering said “most people believe that the best way to manage the shingle is to move it back westwards at the same rate as the sea moves it eastwards. To achieve that, we would have to move about 16,000 cubic metres of shingle westwards from Brighton Marina to the east side of our harbour entrance and the same amount westwards from our western harbour arm back towards Worthing. However, the Port only has the power to move the shingle from our short length of coast on the west side of our harbour entrance to the east side.”
That helps to prevent a build-up of beach immediately west of the harbour entrance but does nothing to prevent big accumulations at Brighton Marina and to the west of our land on Shoreham Beach. So the Port is working closely with Brighton & Hove City Council, Adur & Worthing Council and the Environment Agency to address all of our concerns together. For the last two years, shingle has been transferred westwards from Brighton Marina to the harbour entrance and we are working towards a similar scheme for the west side of the entrance.
We move the shingle in two operations each year, in spring and autumn, and this autumn’s transfer started a week ago moving shingle from Brighton Marina. Next week, the operation will move to the west side of the harbour entrance.