Author(s): Mehmet Salih Turker; Cumhur Ozbey; Serhat Kucukali; Ceren Sengul; Baran Yoğutcuoğlu
Linked Author(s): Cumhur Özbey
Keywords: Pool-weir fish pass ethohydraulics flexible hydraulics elements orifice flow orifice-notch flow
Abstract: Small hydropower plants introduce physical obstructions that hinder upstream fish migration. Pool-type fishways have shown varying effectiveness, with hydropower plants posing specific challenges due to modified flow dynamics. This study investigates the effect of brush block on the movement characteristics of Squalius orpheus (Kottelat & Economidis, 2006) at a pool-weir fishway. We conducted the hydraulic measurements and live fish tests using a 1:2 scale physical model of a pool-weir type fish passage. We carried out experiments with various fish body lengths to observe their ability to hold their positions with and without brush block configurations. The ADV measurements and video recordings revealed that brush blocks reduced high flow velocities and turbulent kinetic energy, creating low-velocity zones where fish could hold their positions. Additionally, the placement of brush block significantly reduced the drift rate 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 habitat for fish at pool-weir fish passes.
Year: 2025