Rules of Engagement: 5

Because of the long and intense impact of humans on European rivers and floodplains, hydromorphological assessment cannot be related to any pristine ‘reference’ condition, but it can focus on the effective functioning of hydromorphological and ecological processes (Bertoldi et al., 2009). Therefore, our approach attempts to discriminate function and human alteration /artificiality emphasising the reach scale within a spatially hierarchical context, and attempts to assess the degree to which there is a potential for function to improve / recover. This approach maps well onto the concept of water bodies that are or are not ‘heavily modified’.