Submitter Withdrawn International Conference on River Connectivity (Fish Passage 2018)

Enhancing the Performance of Vertical Slot Fish Pass by Installing Bristles  (52965)

Serhat Kucukali , Caglar Ozcan

This paper focuses on vertical-slot fishway which is the most common fish pass type around the world. Vertical-slot fishway consists 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 also ecologically important. For instance 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. Accordingly, it is not possible for those endemic fish species to climb classical pool fish passes. The European Union Water Framework Directive requires to ensure the continuity of those species in rivers in order to ensure good ecological status. In this context, it is necessary to make a structural modification to existing 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. In this paper, it has been proposed to place permeable brush blocks in the pools of vertical slots as an innovative concept. The results from a 1:3 scale physical model of a vertical slot fish pass will be presented considering the flow and turbulence structure. The physical model results are compared with the 3D numerical model outputs. The physical model data indicate that bristles reduce  flow velocity and turbulence kinetic energy in the pool; while they increase the lateral velocity gradient and Reynolds Shear stress.