Author(s): Erik Ruijgh; Hans Brinkhof; Tom Buijse; Roel Van Der Schee; Tom O’Mahoney

Linked Author(s):

Keywords: Weirs; Connectivity; Biodiversity; Fish; Meuse

Abstract: Fish migration in rivers like the Meuse in the Netherlands is hampered by weirs and locks as have been built to maintain the water level for navigation in the rivers. The end-of-life of many of these weirs is nearby, and the existing weirs will be replaced in the upcoming years. At the same time the implementation of the Water Framework Directive (WFD) requires measures to improve fish migration and connectivity of water bodies. This combination provides a perfect window of opportunity to design new weirs that provide better passability of weirs for fish. An assessment tool was developed to evaluate the passability of the weirs for various species of fish in the Meuse. Based on the discharge distribution in time and the characteristics of the various objects in the weir-complexes the tool calculates the discharge distribution over each object. In combination with the migration calendars of fish-species, the distribution of fish over each object is estimated. Taking into account specific loss ratios, the loss for each weir-complex is calculated. Finally, the results for each weir-complex are integrated to the losses in the entire river system. The assessment tool provides information on the passability of the entire weir complex for fish, and the role of the various weir complexes in the migration of fish in a complete river system from sea to source. It supports discussions on the selection of measures to improve the passability of weirs and the fish migration in a river system.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0594-cd

Year: 2023