Assessed small hydro power plant Trenčianske Biskupice supports biological flow from derivated channel to original bed of Vah river and hydroenergetical potential uses to make electricity. The purpose of this work was modeling velocities at the intake of small hydro power plant in few conditions: the power station is out of the service and in different types of opened aggregates. The final output is evaluation of velocities and decrements at the intake and design of suitable solution with effective service.