In 1999, the ICPR Plenary Assembly invited the working group ‘Ecology’ to draft a description of the river structure and to map it on a scale of 1:100,000. This description complements the biological surveys of the Rhine carried through in 2000. It underpins the efforts towards creating a habitat patch connectivity along the main stream of the Rhine. As stated in the working programme “Rhine 2020“, a map will visualise this habitat connectivity.
The European Water Framework Directive (EC WFD) setting comparable quality targets for all EU water bodies requires an inventory and assessment of the eco-morphological characteristics of watercourses.
The mapping of river structures aims at an objective and understandable assessment of the ecological functioning of the river and floodplain structure based on a chosen set of indicators (structural parameters). Since the ecological function largely depends on the morphological form and structure of the river bed and the floodplain, water structure criteria are of decisive importance for the ecological assessment of the state of a water body.
The purpose of this inventory goes beyond the mere assessment and documentation of the eco-morphological state of the water body. The aim rather is to create a basis, e.g. for planning and assessing river training and renaturation measures, for tending and development measures and for environmental impact investigations.
The Rhine bordering countries already dispose of a means of assessing water quality. However, investigations into the structure of water bodies have only been carried out since the mid-nineties and have largely concentrated on smaller watercourses. Since the beginning of the eighties, the methods required have been developed in many countries.