Morphological Impact of Coastal Structures

Abstract

In many coastal engineering problems the application of coastal structures to resolve these problems seems to be a proper solution. In a lot of cases, however, the implementation of coastal structures does not lead to the expected situation. Erosion management operations may have unwanted impacts on a coastal system. Decisions on the most appropriate management approach at a given site should be driven in part by the desire to minimise these impacts so as to preserve the natural characteristics of the coast. It is important to bear in mind that erosion of beach and dune areas is a natural and dynamical process and normally should not be regarded as a problem. Problems only arise when erosion threatens human activities or assets, or when the erosion is the result of human interference with coastal processes along an adjacent frontage. A profound study of the actual processes causing the problem should always precede the design of the structure itself. This report intends to provide some clear guidelines to facilitate the design process of coastal structures by discussing several cases and relevant design aspects that seem to be obvious but could easily be overlooked. Especially the recognition of the mechanisms that cause the occurring problem takes a central part in the design process of coastal engineering measures and thus the main emphasis of this report is to awaken consciousness of the mechanisms involved. The cases as discussed in this report are all examples of actual problems. Every solution has its impact on the morphological balance of the coastal zone; this report describes these impacts. It becomes clear after studying all cases that measures to resolve coastal engineering problems are very complicated and adverse effects can be expected in many cases. The main purpose of this report is to make decision-makers in coastal engineering matters aware of the complications that are involved.