OCEANFRONT SHORELINE CHANGE AND ITS LINKAGE TO EBB DELTA REPOSITIONING AND RECONFIGURATION: RICH INLET, NC

Twelve of North Carolina’s 22 inlets border developed, low profile barriers that extend between several sets of headlands in southwestern Onslow Bay and adjacent Long Bay. In their natural state, these diverse inlets have the capacity to promote significant and sometimes cyclical, oceanfront shoreline changes through complex linkages to the ebb-tidal delta. The influence of an inlet on oceanfront change can extend for 2-3km on opposite shoulders. One such system that has exerted a considerable influence on shoreline change is Rich Inlet in northeastern New Hanover County. This unique and relatively large pre-Colonial inlet separates Figure Eight Island, a private residential island, from Hutaff (Coke) Island, an undeveloped barrier to the northeast.

The inlet has been a relatively stable feature over the past two centuries and its movement has been confined to a 1.0km migration pathway. A GIS based analysis of digitized aerial photographs indicates that since 1938 the throat has shifted a net distance of 510m to the northeast; 325m of this migration has occurred since 1993. The most recent period of increased migration coincides with a change in the orientation of the outer-bar channel from 155^o to 85^o. The consequences of this complex pattern of movement for the oceanfront are twofold: first and foremost, swash bar complexes no longer nourish the developed segment of the island; and secondly, the ebb delta no longer affords protection from wave attack. As a result, the northern 2.0km of oceanfront, which has a 70-year history of net accretion, is undergoing rapid erosion. Since 1993 approximately 90-110m of beach/dune has eroded. Erosion will continue until the time the outer bar channel and the ebb delta are naturally or artificially repositioned 900m to the southwest.

An inlet management strategy for this exemplary site will be developed and implemented using hydrographic data and detailed information on oceanfront shoreline change, including the linkage to the inlet and its ebb-tidal delta.