Working group ECOSTAT report on common understanding of using mitigation measures for reaching good ecological potential for heavily modified water bodies

This report is based on information collected via a template on mitigation measures for water bodies impacted by flood defence structures, which was completed by 18 European countries. One of the core activities for the CIS WG ECOSTAT between 2013 and 2017 has been to try to compare the ecological quality expected by different countries for water bodies impacted by flood protection. The process involved the use of a number of workshops and questionnaires to collect relevant information from European water managers.

Hydromorphological alterations due to floods are among the most widespread pressures on water bodies in Europe. Along with storms, floods are the most relevant natural disaster in Europe, in terms of economic costs due to direct damage to infrastructure, property and agricultural land, and indirect losses. As such, flood protection structures and actions are among the main causes for hydromorphological alteration and ecological impairment. Moreover, mitigation measures options, in the case of HMWB for flood protection, are very limited. Any action for mitigation could in fact result into a weakening of flood protection, increasing risk for population and assets. However, in a substantial number of these water bodies, the effects of the alterations are expected to require some mitigation if good ecological potential (GEP) is to be achieved.