Oregon Inlet, the northernmost inlet through North Carolina's barrier islands known as the Outer Banks, is a natural channel conducting flow between the Atlantic Ocean and extensive open bay sounds. As is typical of many natural inlets, navigation through the inlet can be dangerous due to shallow shifting sand shoals. The necessity of continued maintenance dredging and the exposure of commercial and private craft to shoaling and breaking waves indicate that inlet stabilization by jetties is desirable and should be investigated. The design study for the Manteno (Shallowbag) Bay Project included construction and testing of a physical model of Oregon Inlet. Model testing included the study of jetty alignment, length, and spacing and the effects of the jetty structures on tidal exchange and on the flow through Bonner Bridge. It was concluded that the plan 2 jetty alignment with 2,500-, 3,500-, or 5,00-ft spacing would not negatively impact the tidal exchange, storm surge flows, or flow through Bonner Bridge. However, the larger spacings may permit bifurcation of the entrance channel or a more curvilinear channel.

Oregon Inlet is a large tidal inlet through the barrier island system of North Carolina. In 1970, Congress authorized the Manteo (Shallowbag) Bay project which had provisions to stabilize Oregon Inlet with two jetties, deepen the ocean bar channel to 20 ft, and bypass across the inlet sand intercepted by the jetties. This report describes the results of a numerical study to consider coastal and inlet processes in the region surrounding the inlet under existing and planned project conditions. To accomplish the objectives of the study, a system of numerical models called Coastal and Inlet Processes (CIP) Numerical Modeling System was developed. It included models for wave propagation, wave-induced currents and setup, sediment transport within and beyond the surf zone, and profile response (onshore-offshore transport). Results from a separate study on numerical simulation of tides and storm surge for Oregon Inlet were utilized in the present investigation. Originator-supplied keywords: Coastal processes, Dredge disposal Hydraulic structures--evaluation, Hydrodynamics-mathematical models, Inlets, Numerical models, Numerical simulation, Oregon Inlet (North Carolina), Sediment transport, Storm surge, Tides, Waves, Wave-induced currents.