Author(s): Stefan Hoerner; Dennis Powalla; Islam Abdelghafar; Emeel Kerikous; Falko Wagner; Jeffrey Tuhtan; Roland Schumacher

Linked Author(s): Stefan Hoerner, Dennis Powalla, Falko Wagner, Jeffrey Tuhtan

Keywords: Fish passage; Hydraulics; Ethohydraulics; Turbomachinery; Downstream passage

Abstract: Conventional axial pumps used for flood protection in northwestern European marshlands can cause high fish mortality. At Lake Kudensee (Germany), one pump was replaced with a fish-compatible design developed by KSB in collaboration with engineers and aquatic ecologists. The design combined computational fluid dynamics (CFD), the discrete element method (DEM) using "virtual fish," and hydraulic optimization to reduce collision risks. Improvements to the impeller and stator were guided by numerical simulations and verified using sensor probes before live-fish testing. Validation with six fish species showed high recapture rates and mortality below 10% after 48 hours. Although preliminary, the results demonstrate that integrating numerical modeling with biological criteria can substantially reduce fish injury and support the development of fish- friendly pumping stations while minimizing reliance on live-fish testing.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.263

Year: 2026