A hydraulic power system is used in a river, ocean or any other body of water having a current. The method is useful for generating useful electric power from flowing water. The flowing water rotates a turbine and a pump that provides hydraulic power to an electric generator for a clean, renewable energy source. The hydraulic power system tethered to the bottom of a body of water and a positive buoyancy mechanism can be integrated or tethered to the pump assembly. The positive buoyancy can support the pump assembly at a predetermined distance above the sea floor.