Effects of Large Scale Morphological Changes to a Back-Bay System

The Nauset barrier spit breached during a strong Northeast storm in January 1987, creating a new tidal inlet. Nauset Beach has historically undergone an approximate 135 year cycle of spit elongation followed by breaching and new inlet formation. The creation of the tidal inlet resulted in dramatic changes to the hydrodynamic processes within the Pleasant Bay estuarine system including an increase in tidal range, tidal currents, formation of ebb and flood tidal deltas, and an increase in wave energy transmitted into the previously quiescent back-bay region. A notable change was a loss of fringing salt marsh within the estuary. In the 10 year period after the breach there was a 14% decrease in fringe marsh followed by a 5% and 12% increase during the next 11 years. Since 1998, the Town has removed approximately 482,000 yd³ of dredged material that has been used to maintain unarmored important Town beaches along the interior shoreline.