less this happens the larger the **sloping flat" will be, and one can 

 easily see that as long as there is a ^sloping flat" it will be the air 

 erosion that determines the magnitude of the erosion » 



At the cliffs of M^en there are places where there are no "sloping 

 flats'* 5 and at such places a great quantity of material can suddenly 

 fall. Even though this is a rather rare event, usually 30-4-0 years be- 

 tween each fall^ many plans have been made on how to protect the cliffs o 

 However, these plans have never been realized, and we must keep in 

 mind that a complete protection of the cliffs against the attack of the 

 ocean would not be desirable as then the white chalk would lose its 

 beautyo However^ some defense of the cliff would be justified. 



As can be seen from Figure 7 material drifts from the cliffs of 

 M{^en northward^ but on the south coast of this island near the harbor 

 of Klintholmen where the coast is sandy, the direction is westward. 

 Farther south on the east coast of Falster the material drifts south- 

 ward down to Gedser Odde (Gedser Point), and on its west coast the 

 material also moves to the tip of the point. On the south coast of 

 Lolland the material drifts eastward mostly resulting in the formation 

 of a sm.all peninsula near ffyldekrog; but on the western parts of this 

 coast the material must be supposed to move to the west-whioh explains 

 the presence of the small peninsula at Albuen, 



TiVhen the drifting coast material m^eets with an obstacle, for 

 example a groin (Figure 17) then material will be deposited in the 

 corner between the groin and the coast within a belt equal in width 

 to the length of the groin, and as a result the coast line and the 

 depth curves outside it will move seaward. As we know, this is the 

 principle of groins. The more oblique the material -moving pov/er 

 direction in relation to the coast, and the more sand the waves carry, 

 the faster the deposits will be made. If the groin is one of a series 

 it must not be made so high that the wave, when strong v/inds are blow- 

 ing, cannot move some sand over it, otherwise the shore on the leeward 

 side will be too low. The fact is that usually the coast line on the 

 leeward side of the groin will be somewhat landp/ard as compared to the 

 coast line on the other side. If this difference becomes too great, 

 the groin will not function efficiently. Figures 12 and 15-17, 

 illustrate the difference on the two sides of a groin. 



If the groin is high and extends far out in the water, for instance 

 at a harbor, the supply of sand on the leeward side can then be 

 completely arrested with the result that the coast line will retreat. 

 However, there is a great difference in the influence of the vraves in 

 the advance of the coast line to the windward of the harbor and the 

 coast line retreat on the leeward side. The deposit of material on 

 the windward side of the harbor is a direct result of the transport 

 ability of the "vaves. However, the erosion on the leeward side is an 

 indirect result of the wave-attack and can be explained by the follow- 

 ing observations. 



In the beginning, nearly all coast material will be stopped by 

 the harbor. Later, when so much iiaterial has been deposited that it 



13 



