Geography of Kent and Dungeness have been formed by accumulation of alluvium. Kent's principal river, the River Medway, rises near Edenbridge and flows some 25 miles (40 km) eastwards to a point near Maidstone, when it turns north. Here it breaks through the North Downs at Rochester before joining the River Thames as its final tributary near Sheerness. The river is tidal as far as Allington lock, but in earlier times cargo-carrying vessels reached as far upstream as Tonbridge. The Medway has captured the head waters of other rivers such as the River Darent. There are other rivers in Kent, most notably the
Salmon Falls River Salmon Falls River The Salmon Falls River is a tributary of the Piscataqua River in the U.S. states of Maine and New Hampshire. It rises at Great East Lake, Newichawannock Canal, and Horn Pond and flows south-southeast for approximately , forming the border between York County, Maine, and Strafford County, New Hampshire. The Salmon Falls River joins the Cochecho River near Dover, New Hampshire to form the Piscataqua River. It provides hydroelectric power at the New Hampshire towns of Milton, North Rochester, East Rochester, New Hampshire, Somersworth, and Rollinsford, and in Maine at Berwick and South Berwick. The final three