History of Mason's Inlet

Adapted from the US Corps of Engineers Staff - Wilmington District June 25, 1996

Mason's Inlet has been moving to the south at a rate of approximately 110 feet per year since 1938, although the rate of southward movement has not been constant.

Between 1938 and 1960, the rate of southward movement was approximately 120 feet per year.

Between 1960 and 1981, the inlet exhibited a slight northward movement, but was essentially stable.

By 1981, or approximately 4 years prior to the construction of Shell Island Resort, the rate of southward movement of the Shell Island side of the inlet began to accelerate, averaging about 250 feet per year between 1981 and 1993.

From November 1993 to November 1995, the Shell Island side of the inlet moved 650 feet to the south, which represents an average annual rate of 325 feet/year.

The recent acceleration in the rate of the southward movement of Mason's Inlet has been attributed to a reduction in the tidal exchange or flow through the inlet.

The reduction in tidal flow is primarily due to shoaling in Mason's Creek, the estuarine channel that connects the inlet with the Atlantic Intercoastal Waterway (AIWW).

A November 1995 aerial photo of the inlet indicates that Mason's Creek is completely closed.

A hydrographic survey of the inlet, obtained by Century/Von Oesen Consulting Engineers for the Shell Island Homeowners Association in May 1995 indicated that Mason's Creek had shoaled to elevations 2 to 3.5 feet above mean low water (mlw).

With mean high water in the area being approximately 4 feet above mlw, very little tidal exchange occurs through Mason's Creek.

The survey also shows that the main flow channel through Mason's Inlet is approximately 200 to 250 feet wide with a maximum depth of 10 to 11 feet below mean low water.

The overall width of the inlet, measured between the mean high water shorelines, varies from approximately 1,300 feet on the ocean side to around 600 feet at its narrowest point.

Historically, the minimum width of Mason's Inlet has varied from 800 to 1,500 feet.

The present minimum width of 600 feet is a further indication of reduced hydraulic efficiency of the inlet.

Mason's Inlet appears to be unique from other migrating inlets in NC due to the sporadic nature of its migration.

New Topsail Inlet has also migrated a large distance to the south since the 1930's, although the migratory history has been rather constant and therefore more predictable.

Since Mason's Inlet experienced a stable period for over 20 years (1960 -1981), the decision to construct Shell Island Resort appeared to be rather sound at the time since there was no indication that the inlet would migrate southward at anything close to its current rate.

The unpredictable nature of Mason's Inlet is substantiated by the results of a study by Loie and Rick Carraway, published in March 1978.