TUBITAK Project, 2016 - 2018
Hydro Power Plants (HPP) can block the passage of fish migrating up and down-streams or may cause delays. This situation causes a reduction in the fish population. Fish passes are structures that facilitate the upstream or downstream migration of aquatic organisms over obstructions to migration such as dams and weirs. The brush-type fishways consist of a sloping channel into which brushes are fixed which provide velocities of less than 1 m/s for easing the upstream migration of fishes. They are known to provide low velocities, a variety of structures inside the water body and ample of resting room for small, young or weak fish. In the previous studies, the migration of smaller and weaker fishes are neglected. The proposed brush fish pass differs from the conventional fish passage types by providing a nearly optimal migration corridor under uniform and subcritical flow regime for smaller and weaker fishes without any obstructions. This favorable hydraulic conditions are created with the porous structure of the brush blocks and the vibration of the bristles which dissipate the hydraulic energy. Also, vibration of the bristles may help fishes to find the fish entrance by using their lateral lines.
The proposed project aims to investigate the relationship between the hydrodynamics and fish behavior (fish entrance, migration corridors and resting areas) characteristics of brush fish passage which will be established at the existing fish pass of Incirli Small Hydropower Plant (SHP) on İyidere River. İyidere river basin is rich in biodiversity and 13 fish species have been identified in the river. The migration corridor and resting areas of fishes will be determined by using radio telemetry method. For the first time, the fish migration corridors and turbulence structure of the brush fish pass will be monitored and investigated simultaneously at prototype scale. Under the dynamic upstream head conditions of fish pass structure throughout the year, the vertical velocity profiles of different flow regions will be obtained by using Nivus instrument; whereas the turbulence structure will be revealed by measuring the three-dimensional instantaneous velocity fields using Micro acoustic Doppler velocimeter. From those velocity measurements, the distributions of Froude number, Reynolds shear stress, turbulence intensity and turbulent kinetic energy will be obtained. Then the fish behavior characteristics are intended to link to those hydraulic parameters. Also, Froude number will be used as a reference parameter for the migration corridors and resting areas of fishes. Thus, the analysis will be done based on a physical basis and it will contain the most important hydraulic parameters of velocity and flow depth for fish passage design. Here it will be able to achieve results that can be generalized and adapted to other classical-style fish passage. The results will be analyzed as a function of hydraulics and biological variables, including upstream migration to locate fish routes and understand how fish use and process flow information. The results from this study would be useful to fish-pass designers, representative government agencies, and fish biologists. Also, the proposed project is expected to make contributions to sustainable hydropower development.