This deliverable D4.5 summarizes information and experiences for thirteen river types and lists meta-data analysis results based on 844 publications. The report starts with a summary of a literature meta-data analysis, using the REFORM river reach typology. The main component of the report deals with fact sheets and per river type provides a synthesis of restoration experiences describing best and efficient restoration practices, including promising restoration techniques and variables suited for monitoring restoration.

The success of river restoration is often poorly quantified due to poor design, absence of proper monitoring or incomplete documentation. This study is an attempt to overcome this ex-post using the aggregating nature of the ecosystem services approach. In 8 pairs of restored reaches and their adjacent floodplains of middle-sized European rivers, we quantified as many provisioning, regulating and cultural services as possible that were of final value to humans as annual biogeochemical or –physical fluxes, or densities per year, and summed these to annual economic value normalised per area. 

 Summary

An increasing number of river sections have been restored in the past few decades but only a small number of these projects have been monitored. The few monitoring studies mainly investigated single organism groups, reported contrasting results, and rarely did investigate the influence of catchment, river or project characteristics. In this study, we compiled a harmonized dataset on the effects of hydromorphological river restoration measures on biota based on a standardized monitoring design to minimize scatter due to methodological differences. A broad range of response variables was recorded to draw conclusions on the effect of restoration on biota in general, including habitat composition in the river and its floodplain, three aquatic and two floodplain-inhabiting organism groups, as well as food web composition and aquatic land interactions as reflected by stable isotopes. Additional data on factors potentially constraining or enhancing the effect of restoration were compiled to identify conditions which favour restoration success. The main focus was dedicated to investigate the effect of restoration extent (as indicated by restored section length and restoration intensity).

An increasing number of rivers have been restored over the past few decades but only a small number of these projects have been monitored, and hence, the knowledge on the effect of river restoration on biota is limited. Nevertheless, monitoring results of several projects are available in peer-reviewed scientific literature and have been compiled in recent research projects. The objective was to evaluate the effect of hydromorphological restoration on biota based on these existing data. Specific objectives were to quantify restoration success, to identify catchment, river reach, and project characteristics which influence (either constrain or enhance) the effect of restoration, and to derive recommendations for river management. The study is complemented by a satellite topic on urban river restoration.

WP4 evaluates effects of river restoration by analysing existing data as well as performing field studies on paired catchments. The field studies will use examples of restored sites in which either one large scale measure (flagship restoration site) or smaller restoration measures (small restoration site) have been implemented. These restoration sites will be compared to “control sites” that are situated upstream and are still degraded (nested design). Deliverable 4.1. documents the abiotic and biotic parameters to be recorded at the case study sites and provides a description of the methods for field investigations in 2012 and 2013 including manuals, field forms and protocols.