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|Title:||Impacts of navigation channel maintenance dredging on the coastal processes of Chatham, Massachusetts|
|Authors:||Stauble, Donald K.|
|Publisher:||Coastal and Hydraulics Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||ERDC/CHL TR ; 01-26.|
During an extratropical storm on 2 January 1987, a breach formed in a barrier spit opposite the Town of Chatham on the southeast corner of Cape Cod, MA. An inlet rapidly developed at the site of the breach from wave action and tidal currents. Typical inlet morphology developed at this new inlet, including a large ebb shoal and swash platform and a single main ebb channel on the ocean side. In the narrow elongate bay, a north and south flood tidal shoal developed over remnant sand shoals. Over time, the inlet throat widened as the adjacent barrier spits recurved back into the bay. Navigation through this quickly evolving inlet system became difficult with channel shoaling and migration. Dredging of parts of the navigation channel has been undertaken since 1989 to maintain an opening for commercial fishing and U.S. Coast Guard interests between the Atlantic Ocean and the Fish Pier. This dredging removed only a minimal volume of the material, and has had little impact on the large dynamic system. Inlet morphology evolution include the welding of the South Beach to the mainland beach, closing off south Chatham Harbor and returning the system to a single inlet system in 1992. By 1995, a north ebb channel had formed creating a two-ebb channel inlet. Major changes have occurred in the entrance channel and anchorage area of Aunt Lydia's Cove. The growth and migration of the north flood shoal has changed this channel configuration which has required several dredging events to maintain navigation to the Fish Pier. Based on the flood shoal area morphology evolution patterns, new dredging boundaries were recommended for maintaining the navigation channel in a rapidly evolving system. A review of the historic 140-year cycle of inlet formation and evolution at Chatham Inlet suggests that, while there are slight differences, the general trend in inlet change is following the two previous inlet formations. Based on the general historic evolution and the detailed 13-year present history, guidance for sand management and future navigation channel stability have been addressed.
|Appears in Collections:||Technical Report|