APPLIED MODELING OF COASTAL PROCESSES: EUROPEAN PERSPECTIVES

While US applied models of coastal processes have received a modicum of critical appraisal, current practice in Europe has not benefited from such a process. A preliminary review of the nature and use of applied coastal models in Europe is presented here.

A wide variety of European applied coastal processes models are used in the design and assessment of coastal works, and to predict the impacts of various human interventions. The use of such models typically follows the practice of 'calibration' against historical data or field data in which a 'blind' simulation is adjusted to provide the 'correct' answer. This 'calibrated' model is then applied in an effort to simulate future conditions.

The majority of models are deterministic and generally based upon a mix of physical laws and empirical relationships. They are thus amenable to inclusion of several adjustable input parameters within the physical relationships included in the model calculations. This gives an apparent sophistication to the models in that the user has the ability to define the input parameters for a suite of dynamic, material and topographic factors (for example wind speed and direction, tidal currents, wave period, height, spectral characteristics, sediment grain size, sorting, spatially and temporally variable nearshore profiles, mixed wave and current transport). Behind this apparent sophistication, however, lies the fact that many of the relationships being modelled have never been proven in nature.

A significant constraint on the analysis of European coastal models is that they have typically been developed by companies who do not wish to reveal the model detail in a competitive market. Thus, published descriptions of models (when available) are typically imprecise. Some are available for purchase under licence under which circumstances they are utilised as 'black boxes'.

The lack of detailed model description, peer review and model validation, has not halted the use of such models or apparently prompted criticism. Indeed, many European contractors use their own proprietary models that have never been subject to peer scrutiny outside the group of individuals who developed them. Such commercial considerations are a significant barrier to rigorous criticism of European models.