Coastal environment assessment procedure for sustainable wastewater management in tropical islands: the Mayotte example

The recent evolution of the coastal environment is characterized by an increase of human potential impacts: coastal zone is located at the cross-road of sectoral issues which give rise to a number of often competing uses. Today, the main challenges in the coastal environment management are not derived from “technical problems” but correspond to the global coastal management and to the means to harmonize the different uses. This new approach has generated the need to apply systemic concepts which are able to describe and analyze large and complex systems. In the coastal zone — and especially in sensitive environments such as tropical island surrounded by coral reefs, lagoons or boat channels — one of the major challenges is to conciliate the waste waters and pipe outfalls management and the ecological preservation. The paper presents the results which have been obtained with a global approach for the definition of a sustainable wastewater management strategy in highly sensitive coastal areas located in Mayotte, (Comoros archip, Indian Ocean). This example allows to explain and identify the necessary tools and essential procedures as hydrodynamic modelling or public participation. From this application, a procedure for a coastal environment assessment procedure is formulated and proposed.