Intertidal flats are very sensitive coastal environments. They support large communities of highly specialised fauna and flora and are subject to physical processes that combine hydrodynamic and sedimentary processes that are highly sensitive to change. An added factor to the difficulty of studying and monitoring intertidal flats and their environment is that they may be situated near a human settlement that requires protection from flooding or inundation. Monitoring sensitive intertidal flat ecosystems to obtain precise and updated information on its geomorphological and biological state is a challenging task for coastal scientists, managers and engineers, who have to deal with both, the conservation of the environment and human demands.

This paper describes a monitoring programme designed to establish, for a sensitive intertidal flat, the state of a comprehensive number of environmental factors prior, during and after the construction of sea defences. The rigorous assessment of environmental impact has been the backbone of the design and implementation of this monitoring programme based in Newtownards, at the Northern end of Strangford Lough in Northern Ireland. The Lough is a major wildlife and scientific resource that is subject to several domestic conservation designations as well as being considered, under European Community Directives, as a site of importance for nature conservation. The individual components of the intervening forces and responses have been identified and studied on a high-resolution spatial basis whilst not interfering with the fragile ecosystem. Biological and geomorphological parameters were identified for monitoring. Surveys comprised plant ecology, spatial distribution of density and type of vertebrates and invertebrates, sedimentological analysis (both historical and contemporary), hydrodynamic controls and topographic evolution as well as salt marsh shoreline monitoring. A wide range of technologies have been implemented to achieve a monitoring programme that that can be fully integrated in a Geographic Information System minimising post-processing times for interpretation and data-base access. Some of the techniques include the use of an ATV mounted DGPS with sub-centimetre accuracy for topographical and biological surveys, colour infrared digital airborne image acquisition using the Kodak DCS460 and image analysis, as well as numerical wave modelling of wave propagation. A virtual monitoring centre is being created as the main outcome of this project. The participating institutions (research, management and the public) will be able to access the electronic libraries and maps via an integrated web-based database. This project has been approached as a research and development programme that serves as a model for integrated coastal zone management in sensitive tidal flat ecosystems.