The Potomac is the longest and most diverse river system in Maryland, reaching from the cold, high plateau of the Alleghenys to the broad waters of the Chesapeake Bay and tidewater. This section begins with paddling over the rubbly ruins of the C&O Canal Dam No. 2 and through a maze of islands, rocks, and easy riffles. These riffles are perfect for novices. Below here, the river is split by the three and a half mile long Watkins Island and dozens of other islands and the water is flat all the way to Great Falls. The scenery is beautiful on this stretch. Take out at Great Falls Park on the left and be sure to take out well above the Washington Aqueduct water supply dam. Washing over this dam would be nasty and Great Falls develops just downstream.