ABSTRACT
Human intervention, including regulation of rivers and streams, construction of water intakes and dams poses a threat to ichthyofauna. Major threats to the migrating fish are hydroelectric power plant’s water intakes. However, much smaller intake constructions supplying drinking water is also a problem for ichthyofauna. The water intakes may lead to injury or death of fish. One of the widely used methods to protect fish at water diversions is to provide a physical barrier that prevents fish from being entrained into the diversion (Department of Fisheries and Oceans 2006). Cylindrical wedge-wire screens are considered as a technology that has potential for effectively reducing entrainment and impingement of fish eggs and larvae at water intake structures. In order to protect fish from entrainment, special devices known as physical barriers are installed in water intakes. The water inlets are equipped with a cylindrical wedgewire screen. Inside the wedge-wire screen there is a deflector. The purpose of the deflector is to equalize the velocity distribution on the surface (Jamieson et al. 2007). It is obtained thanks to properly designed differential size of slots (Taft 2000). The wedge-wire screens parameters should be properly designed what is crucial to ichthyofaunal protection. There are few important factors such as inlet velocity, mesh size and cylinder outer surface (Department of Fisheries and Oceans 1995). Since traditional designing of the cylindrical wedge-wire screens is quite imprecise, CFD modelling seems to be quite adequate. Analysis of flowrate velocity and streamline distributions are possible to conduct based on computer simulations.
