Masonboro Island

Figure 1. This land is all of Masonboro Island that is above high tide. (Photograph by the author. More about the photograph)

The two islands visited on this trip, Masonboro and Topsail, have very low sand volumes. Masonboro Island is a part of the National Research Reserve system and is completely undeveloped. Topsail Island has been developed for residential use and has the roads, water supplies, and other infrastructure features needed for houses, condominiums, hotels, and other characteristics of a beach resort.

Both Masonboro and Topsail are far from major rivers and neither is crossed by old shorelines, so neither has access to the sand that can be supplied from these sources.

In addition, Topsail and Masonboro have ridges of hardened material off their coasts (calcareous rock off Topsail, mud off Masonboro). In both cases these ridges reduce the amount of sand that is returned to the island’s beaches once it has been moved offshore by storms. In neither case is this process of natural beach nourishment completely eliminated, but in both cases it is reduced to levels below that which occurs where offshore ridges are not present.

Figure 1 shows the flat beach and berm that make up Masonboro Island’s only land above the high tide line. In the distance to the left you can just see the beginning of the intertidal salt marsh on the landward side of the island and in the distance on the right you can see the ocean at about mid-tide level. There is really not much else to see. The beach, berm, and water are all at essentially the same elevation in a flat landscape.

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