Abstract: A system usable for dredging may include a suction bypass system for automatically maintaining a sufficiently high, liquid flow velocity. Preferably, a flow sensor monitors flow velocity and when the monitor flow decreases to an extent that plugging may occur, a liquid bypass valve is opened and an intake line valve is closed until the flow velocity increases whereupon the valves are returned to their original positions. An automatic level cut removes a relatively constant layer of material from a contoured bottom. The illustrated automatic level cut process comprises adjusting the force with which the suction head engages the bottom, moving the suction head in a direction opposite to the direction of the swing of the boom to keep the suction head pointing straight ahead, and maintaining the suction head to stay substantially level with the bottom even though the angle of the boom increases to the surface of the water body.