Coastal erosion & defence at South Beach, Studland

All around our British coasts we can see evidence of coastal erosion. It seems to be happening at an ever increasing rate in recent years. It is especially noticeable where the edge of the seashore is composed of softer rocks or sand dunes, for example. The coastline of Dorset in England, like many other places, is vulnerable to coastal erosion. Studland Beach near Poole Harbour is a case in point.

The shore of Studland Bay is divided into three stretches: South Beach, Middle Beach, and Knoll Beach. At South Beach, we have already seen how the burrows of small marine worms help to break up the surface of the chalk that underlies the beach in an almost imperceptible process called bio-erosion. However, the physical, hydraulic, and abrasive action of high energy destructive storm waves on the soft materials of the cliff is the coastal process responsible for immediately obvious damage with a wearing-away and break-up of the rocks and other materials on the upper margin of the seashore.

This destructive action of waves is most apparent from the number of small land slips, and trees that have collapsed to the beach, as cliff material [like London and Creekmoor Clays, and Broadstone and Oakdale Sandstones] has washed away from beach level. This has caused the undermining of the cliff deposits, and the eventual fall of material from higher up. There are a number of trees lying in a horizontal position at the base of the low soft cliffs on South Beach.

Where the ground level changes from cliff top to nearer beach level, the wearing away of the soil by the waves means that the trees now seem to be growing directly from the seashore with nothing but sand and pebbles around their roots and trunks. Just a short distance north of these beach-bound trees there are numerous beach huts on the slightly higher ground behind the shore. They are in a vulnerable position. Here the soft ground on which the huts stand is protected from the destructive force of wave action and flooding by the emplacement of stone-filled wire cages known as gabions. These are stacked to form a barrier wall of harder material that is more resistant to erosional coastal processes.