Assessment of coastal environmental quality based on littoral community cartography: methodological approach

Abstract

In this study we present a new methodology for monitoring water quality based on the cartography of rocky benthic communities in the littoral zone. Littoral communities thriving in the selected coast are cartographied from a small boat and the cartographic information is transcribed to a GIS. With the use of spatial databases and geographic information system technology (GIS) it is possible to know not only the distribution of rocky benthic communities along the coast but also to obtain an environmental quality index giving a “quality” value to every community. This index takes into account the length of the coast covered by each community, a value of ecological quality of each community obtained by expert judgement, and a correction by different parameters other than water quality involved in the distribution of littoral communities (e.g. natural or artificial substrate, type of coast) which has been obtained with an accurate study of the distribution of littoral communities in reference zones. This index, named Ecological Quality Ratio, fulfils the requirements of the Water Framework Directive. (2000/60/EC).