Morrisville is located on a very unique stretch of the Delaware River. It is here that the river tumbles off the Piedmont Plateau onto the coastal plain, forming the "Falls of the Delaware", on its way to the Atlantic Ocean. From this point on, the Delaware River is controlled by the ocean tides. It is actually the falls that keeps the tide from pushing further inland. As the tide pushes up the Delaware Bay and Delaware River, it is restricted due to the narrowing of the river, because of this the tides can be quite large here. An eight foot tide is not unusual      
These first four pictures were taken from under the railroad bridge looking down stream, note the hook on the pier.
These next two pictures show the tide differences between the railroad bridge and the Route 1 bridge.
Looking under the Route 1 bridge, toward the "Trenton Makes" bridge. These boulders mark the end of the Piedmont Plateau and form the "Falls of the Delaware". These rocks do go under water at high tide, but a short distance upstream the tide is hardly noticeable.
The last four pictures show the remains of the creek that made the "Island" an island, and where it rejoins the river near the Route 1 bridge. At one time there were tunnels under Bridge Street (in the background) that the water flowed through.