LITMIR.BIZ

      Lowestoft is in an exposed position, and is the most easterly point of this country. As explained here, the coastal drift is from the north, and much is held at Yarmouth, Of recent years also changes in the form of the sand banks off shore and of the set of the currents are held to be contributory causes of the severe erosion at Lowestoft.

The Isle of Sheppey affords another instance of loss. Between Scrapsgate and the jetty, south-east of Warden Point, along a total length of five and a half miles, the loss of land between 1865 and 1906 was 103 acres, or taking an average for the whole length of the line, an annual loss of 3.8 feet. At Warden Point itself the loss reached 9·7 feet a year on an average. The subsequent evolution of the part near Warden Point is shown in Figure 5.¹

      Erosion takes place in harder rocks and cliffs, but as a rule very slowly. Records are scarce, and usually only occasional big slips, if the structure is favourable, or some spectacular change, are remembered. Chalk is a rock of intermediate hardness. Near Birling Gap, west of Beachy Head, no record is kept, but there is an estimated loss of two feet a year. This, however, is very erratic and irregular in its incidence. At Seaford there is said to be some erosion of the Chalk cliffs, but what changes occur appear to be mainly the result of frost action.

      All round the coasts of Great Britain other examples could be found, and doubtless the reader will know some of them. Generalisations should be avoided, or at least used with discretion. The amount of erosion even in soft cliffs is often exaggerated, and the figures given show how it can vary with time. Local exposures of boulder clay such as those south of Aberystwyth, or those west of Criccieth, retreat comparatively quickly. These are mentioned because Cardigan Bay may all too readily be dismissed as a coast wholly formed of hard rocks. The damage in 1938 at Aberystwyth itself is worth bearing in mind.

      Erosion is not a serious problem in Scotland. There are some places which are affected, but seldom to the extent of those in England.

      FIG. 5 Erotion in the Isle of Sheppey

      (After F. W. S. Stanton and Ministry of Town and Country Planning)

      The Royal Commission in 1911 reported on several cases including, for instance, the Wigtownshire coast of Luce Bay between Sandhead and Drummore where local erosion has cut into the main road. Along the coast of Ayrshire and also in Arran the raised beaches (see here) which closely follow the coast and carry the main road are subject to some erosion. At Golspie, in Sutherlandshire, the erosion was estimated at two yards a year, a very high rate for any part of the Scottish coasts. It is still active at this place. There is also local erosion at several places along the coasts of Moray and Banff, including the Bay of Gamrie in which the picturesquely placed villages of Crovie and Gardenstown are situated. There are several other places along the east coast where erosion occurs, but in nearly all the Scottish examples the reason given to the Royal Commission was the same, namely, the local removal of shingle. It is instructive to quote from their Report: “This erosion (on the East Sands) has been going on for a long time, and within the last ten years the coastline appears to have receded about 20 or 30 feet. The erosion principally affects the property belonging to the University of St. Andrews, and it appears to have been accelerated by the removal of materials under the authority of the Corporation—who claim the foreshore—from the beach. The representative of the Corporation who gave evidence admitted that the removal greatly assisted the erosion.” Removal of beach material may be important. The force of the sea expends itself on the beach, and if sand and shingle are indiscriminately taken away, especially from places where natural replenishment is slow or absent, erosion is bound to occur.

Conditions at Stonehaven afford an interesting example of local erosion. In recent years the town beaches have suffered a continuous loss of material. The littoral drift carries away material to the south, but the supplies from the north have not kept pace. Every now and again considerable quantities of material are deposited on the Stonehaven beaches, and across the mouth of the River Cowie. This in turn may cause the river to change its course near high-water mark, and also, since its velocity is thereby reduced, makes it unable to carry as much suspended material as usual to the sea. Thus a gradual rise in the level of its bed can take place. If then there follows a heavy flood, the impounded water of the Cowie breaks through the shingle, and this occasionally leads to severe scouring of the bed and banks of the river. A sudden lowering of the river bed by as much as four feet has been known to occur in a few hours following a single rain storm.¹