Review on costs and benefits of river restoration. Data were collected in a database to empirically investigate the costs of river restoration measures throughout Europe. Also, a summary of restoration planning and the specific measures which can inform the future development of cost-benefit analysis and their application were introduced. A non-exhaustive review of peer-reviewed literature and technical reports was conducted to elicit the effects of individual measures, providing a basis for the analysis of restoration benefits.

Building on existing data, this task reviewed and analysed the available knowledge on biological responses to hydromorphological degradation and restoration. The effects of hydromorphological changes on aquatic plants, macroinvertebrates and fish have been analysed on the one hand with regard to specific requirements of species as potential sensitive indicators and on the other, with regard to limitations of species due to hydromorphological forces aiming to derive thresholds and boundaries of impacts as well as guidelines for rehabilitation.

This is a bibliographic review concerning the effects of HYMO pressures on hydromorphological processes and variables resulting from both degradation and restoration. It further provides a tool to identify gaps in present HYMO knowledge, which is needed to improve our understanding of the mechanisms that control degradation-restoration processes. The following groups of HYMO pressures are addressed: hydrological regime alteration, river fragmentation and morphological alteration.

Several ecological and hydromorphological assessment methods have been developed in different countries during the last years, with notable differences in terms of aims, scales, and approaches. In many cases, strengths and limitations of the different types of methods are not yet sufficiently known, although they are widely used in some European countries.