The paper summarizes the results of the work done in orders to evaluate the possibility of changing the function and utilization of rubble dosing dam on the Wieprzówka I mountain stream in order to create an artificial lake and ensure that the water level in the reservoir remains the same. The artificial lake will be valuable from the point of view of tourism and what is more it will improve the water retention of the valley. A rubble dosing dam protects the river bed by reducing the bed slope and water velocity and what is more by controlling the bedload transport so that accumulation takes place up the dam. The dam does not stop bedload transport because there are openings which dose the fine material. The fine material can be transported even if the rubble dosing dam is filled up, so the hydrodynamic equilibrium and the connection between upstream and downstream sections of the river is maintained. Hydraulic seal of the rubble dosing dam and the exploitation of accumulated bed material will break the hydrodynamic continuity of the river channel and cause erosion below the dam – a process against which the dam should protect. Field measurements carried out on ...