Author(s): Mehmet Salih Turker; Cumhur Ozbey; Serhat Kucukali; Ceren Sengul; Baran Yoğutcuoğlu

Linked Author(s): Mehmet Salih Turker

Keywords: Pool-weir fish pass; Ethohydraulics; Flexible hydraulics elements; Orifice flow; Orifice-notch flow

Abstract: The absence of fish passages in hydraulic structures or the inefficiency of existing ones disrupts the migration pathways of aquatic organisms, resulting in significant and long-term adverse effects on biodiversity. This study investigates the effect of brush block and flow regimes on the movement characteristics of Squalius orpheus (Kottelat & Economidis, 2006) at a pool-weir fishway. The hydraulic measurements and live fish tests were conducted using a 1:2 scale physical model of a pool-weir type fish passage. Experiments were carried out with various fish body lengths to observe their ability to hold their positions with and without brush block configurations with two flow regimes (orifice flow and orifice-notch flow). The ADV measurements and video recordings revealed that brush blocks reduced high flow velocities and Reynolds shear stress, creating low-velocity zones where fish could hold their positions. Additionally, the placement of the brush block significantly reduced the drift ratio of Squallius orpheus individuals in the pool. With the placement of the brush block, the fish drift ratio decreased from 76% to 48% for the orifice flow regime, and it decreased from 86% to 19% for the orifice-notch flow regime. These findings highlight the potential of brush blocks to enhance hydrodynamic conditions, providing effective refugial habitats for fish at pool-weir fish passes.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P2100-cd

Year: 2025