Fish protection at reservoir intakes with electrified bar screens

Many reservoirs of storage hydropower plants and pumped storage hydropower plants are connected to natural river sys- tems and thus are often inhabited by fish. When water is with- drawn from these reservoirs to generate hydropower, fish can get entrained into the water intake structures and the head race tunnel. The necessity of adequate measures to minimize fish mortality at hydropower plants is increasingly demanded in legislative procedures when new hydropower plants are constructed. Furthermore, many operators of hydropower plants develop an interest in this topic to realize an ecologically improved generation of hydropower and improve their image. Due to the relatively high head of (pumped) storage hydro- power plants the resulting fish injuries from a turbine passage can be expected to be severe or lethal. The technical require- ments of the intake structures are often difficult to match by using bar racks with small bar clearances to physically prevent fish from a passage. Electrified bar racks with moderate bar clearances are an option to synergize low maintenance effort and low hydraulic losses with good fish protection.