Coastal structures are built for the purposes of shoreline stabilization, protection of the land against waves and surges, harbour protection and for fixing the position of a river mouth or tidal inlet.

A problem, like local erosion, can be due to some strictly natural effect which conflicts with human interest, or it can be due to human-induced changes. In order to stress the fact that each construction is not only a solution for a coastal problem, but also a possible cause of new coastal problems, the previous chapter discussed the consequences of constructing works within the coastal zone. The present chapter outlines some basic features of common coastal structures.

Besides the large works discussed in this chapter, various small-scale activities are also performed in order to protect the coast. Among these are the planting of marram grass (see Fig. 69) and the erection of sand fences in order to increase the trapping capacity of dunes (see Fig. 70). Although less spectacular, these 'constructions'
contribute significantly to coast protection.

An amusing, small coastal 'construction' is the planting of artificial seaweed on the seabed at Norderney, Germany (see Fig. 71). The polypropylene strips are connected to a steel mat. The retarded seabed currents induce sedimentation.