TUBITAK Project, 2017 - 2019
The proposed project focuses on vertical-slot fishways which are commonly built in rivers around the world. Vertical-slot fishways consist of a series of pools which are separated by long and short baffles at regular intervals. However, vertical slot fish passes are designed for large fish which have economic value, such as salmon and trout. But, in rivers there are small-bodied and weak-swimming capacity fishes which are ecologically important. The European Union Water Framework Directive, which was also adopted by Turkey in 2012, is required to ensure the continuity and monitoring of these species in rivers in order to ensure good ecological conditions. In this context, it is necessary to make a structural modification to vertical slot fish passes to allow the passage of such small-bodied and weak swimming capacity fish. In this context, it is necessary to make a structural modification to vertical slot fish passes to allow the passage of such small-bodied and weak swimming capacity fish. In the previous studies, impermeable hydraulic elements were placed in the pools to dissipate the flow energy and prevent turbulence. However, this configuration has caused two different turbulence fields around the obstacles and has not been particularly beneficial for the passage of small fish species. Within the scope of the project, it is proposed to place permeable brush blocks in the pools of vertical slots as an innovative approach. Recent laboratory experimental works showed that by placing brush blocks in the vertical slot pool, the flow energy is effectively dissipated by the vibrations and bending of the bristles leading an about 30 % and 40 % reductions in the average resultant velocity and the turbulence kinetic energy in the pool.
In Turkey, there are 382 freshwater fish species and about 1/3 of these species are endemic. Some of those endemic fish species have a body length of 5 cm. So It is not possible for those endemic fish species to climb classical pool fish passes. So, structural modifications are required for such local fish species in those fish passages. In the scope of the proposed project, , a pilot study has been planned at the vertical slot fish passage Çataloluk Small Hydropower Plant (SHP), which is located in Ceyhan River Basin in Tekir Creek. Ceyhan Akarsu basin is very rich in terms of biodiversity and 20 fish species have been identified in the stream and two of these species are endemic. A fish monitoring study was carried out in this SHP plant by using PIT tag method within the scope of TÜBİTAK 1001 project titled "Determination of Migrations, Habitat Preferences and Activities of Fish Passages in Fish Populations in the Ceyhan River". At the end of this fish monitoring study, it was found that fish migrated upstream between May-June period and small and juvenile fish, which are extremely important in terms of ecology could not migrate through the vertical slot fish passage.
The purpose of this study is to reduce the turbulence kinetic energy in the vertical slots by placing brush blocks in the vertical fish passage of Çataloluk to provide favorable hydraulic conditions for different fish species. In this study, the conservation of energy principle will be used. In this context, it was aimed to collect 3D point velocities and turbulence quantities by using micro ADV and flow depths by using ultrasonic distance sensor in a measurement mash in a pool for 2 years during the migration time of fishes (May-July). The measuring grid was not evenly distributed over the base area, since it was to be expected that larger velocity gradients would occur in the area of the jet and near the wall. A measuring grid with 7 lateral sections and 7 longitudinal sections as well as 4 fair planes were selected. The paths, velocities and acceleration of fish of different species in the pool will be determined by the combination of PIG tag and image processing composite technique. The Adaptive Gauss Mixture Model will be used in image processing method. The Euler approach is intended to use to determine the turbulence characteristics (turbulence kinetic energy, Reynolds shear velocity, resultant and power velocity) of the pool; whereas the Lagrange approach will be used to determine the different fish species migration characteristics in the pool. Thus, two different configurations performances (number of fish passing through the structure, species diversity, size of the fish) and turbulence characteristics will be compared. The vibrations of the bristles can be a hydrodynamic factor that can guide fish by using their lateral lines during migration. For the first time in this study, the vibrations of the bristles will be examined as a stimulus for the fish movement. In addition, the literature lacks form a study that examines the turbulence structure and fish migration patterns at a prototype scale in vertical-slot fish pass simultaneously. Accordingly, the proposed project is expected to fill the gap in the literature. The main objective of this research project is the development of applicable configurations for vertical-slot fishway under consideration of fish-ecological aspects. Since the response of fish to different flow patterns is not yet clear, all results will be evaluated according to fish-ecological criteria in order to derive reliable designs. The implementation of the proposed innovative design in the existing vertical slot fish pass is cost efficient and ease of installation.