The MMA’s primary surface water supply is the Allegheny River. The Allegheny River begins as a spring in a farmer’s field in the upper Appalachian Mountains of northern Pennsylvania. It then collects in the Allegheny Reservoir (Kinzua Dam) and flows to the confluence with the Monongahela River. The Allegheny River Watershed encompasses 11,770 square miles and includes most of Western Pennsylvania and parts of South West New York. The MMA water is drawn from the Allegheny River near Oakmont, Pennsylvania. The quality of the water from the Allegheny River can be affected by mine acid drainage, sewage treatment plant discharge, agriculture and livestock runoff, leaking underground and under river pipelines, leaking chemical storage tanks, river barges and railroad cars transporting chemicals.