Abstract: A pumping apparatus used to move manure from a collection chamber through a conduit into a storage or detention pond. The pumping apparatus has a flow-through piston reciprocated with a reversible hydraulic fluid motor. The piston has a pair of gates pivotally mounted about separate generally upright axes at the forward end of the piston to control one-way flow of manure through the piston. A reciprocator operates in conjunction with a pump to alternately supply fluid under pressure to opposite ends of the fluid motor and thereby reciprocate the piston.