Linking form and function: towards an eco-hydromorphic approach to sustainable river restoration

1. River restoration is now widely undertaken and may be considered an increasingly important aspect of river management. Recent developments in European legislation (Habitats Directive and the Water Framework Directive) should give further impetus to river restoration across EU member states, as this legislation places greater emphasis on the processes that support river ecology. 2. Traditional river restoration approaches have been reach-focused and opportunistic, capitalizing on flood defence works and the cooperation of sympathetic landowners. 3. Furthermore, many schemes have been species- or habitat-driven and, thus, have sought to recreate channel forms believed to be favoured by particular species or associated with particular habitats. Such approaches have not always given due attention to the underlying geomorphological processes that create channel form and, consequently, the schemes have not been self-sustaining, requiring continued management input. 4. Consistent with the ethos of the Water Framework Directive, an eco-hydromorphic approach to river restoration is proposed here. This approach views spatial and temporal heterogeneity as fundamental characteristics of fluvial systems and advocates recreating a framework within which natural processes, such as sediment transport and nutrient dynamics, can occur. 5. Mesoscale habitat approaches are considered as one possible way to plan and achieve this framework, providing the potential to link the wide range of spatial and temporal scales that characterize river systems. 6. It is argued that river restoration will only be sustainable if it is undertaken within a process-driven and strategic framework with inputs from a wide range of specialists. Such an approach needs to be reviewed constantly in light of appraisal and monitoring of previous river restoration schemes. Copyright (C) 2003 John Wiley Sons, Ltd.