PHYSICAL IMPACTS OF CLIMATIC-CHANGE ON DELTAIC COASTAL SYSTEMS .1. ANAPPROACH

The evaluation of the impact of climate change on deltaic systems impl ies studying a multi-component system in which the complexity of links is high enough to present doing it as a whole. Because of this, it is a reasonable approach to study separately the behaviour of each eleme nt, to be afterwards linked into a general conceptual model for deltai c behaviour. Moreover, in the case of largely regulated deltas, the ma in impacts of climatic change will be marine-related since those relat ed to the catchment areas will be severely damped by river regulation and management policies. This fact implies that coastal fringes may be come the main frontier between the delta and climatic change effects. In this context, a methodology to study climatic change impacts on del taic coastal fringes is here presented. It will be further developed o n two companion papers dealing with the study of driving terms and coa stal response. As coastal processes act at different time and space sc ales, determining the 'reference' - initial - situation must be done t aking into account the inherent system dynamics. It is thus unrealisti c to characterize the initial stage as a static one. In order to avoid this simplistic approach, a comprehensive approach to the coastal sys tem must be employed, with three different scales (long-term/large sca le, medium term/scale and episodic).