Ecological evaluation for river meandering restoration. A case study on five Flemish rivers

Ecological data provide crucial information to evaluate the present status of vegetation, fish andor wildlife communities. The assessment of the success (or failure) of river restoration (or rehabilitation) is only possible when ecological information was gathered before implementation. This means that monitoring is a crucial step in the planning of restoration projects and that it has to start in a very early stage of the planning process. During this project it was not our intention to start an extensive monitoring campaign. We decided to do a pre-restoration evaluation of the selected sites to see if restoration will most likely lead to a significant increase of the ecological value of the river system. In this paper we evaluate the fish assemblage and the macro-invertebrate communities, mainly on population level. These results were used to indicate the need for restoration. In one case (the Kemmelbeek) the pre-evaluation showed that restoration at the present state would probably not result in a higher ecological value. In this case, restoring a good water quality will be of higher priority than restoring meanders. On the other hand, meander restoration of 4 other sites will result in a higher ecological value. So these sites were proposed for remeandering.