Cost-efficiency aspects for fish passage restoration in the Ruhr River Basin

Abstract

The protection and sustainable management of the aquatic ecosystems is the central aim of the European Water Framework Directive. Due to the aspiration for good ecological status of the water bodies free fish passage will play an important part in river basin management. The Ruhr River has seen severe anthropogenic modifications due to urbanisation and industrialisation in the 19th and 20th centuries leading in the existence of approx. 1300 weirs within the Ruhr River Basin. The majority of the barriers are assessed as not passable or restricted passable. Against this background the Ruhrverband made a holistic approach towards restoring fish passage within the Ruhr catchment. Besides the scientific and technical aspects, such as the determination of potential (spawning) habitats and the development of measures in order to reach them, they also considered cost-benefit-ratio considerations for the Ruhr catchment as a whole as well as for site-specific designs of fish passage structures. Various benefits were evaluated taking into account different fields of economic interest. The model of financing all necessary measures should involve all responsible parties benefiting from the water utilizations. Such a mutual procedure delivers a fair cost distribution as well as an efficient implementation of measures.