Ocean City, MD -- an urbanized barrier island

Photo courtesy USGS

Development's Effects on Barrier Islands

Development has important effects on barrier island ecosystems, which are dynamic systems by their nature. Several environmentalists and noted geologist Orrin Pilkey, of Duke University, have spoken about the dangers of building on barrier islands. Let's look at two barrier islands that have been drastically changed by development.

Ocean City, Maryland

Ocean City, which is located at the southern end of Fenwick Island along Maryland's eastern shore, has been a popular beach resort for a long time. In the 1920s, several large hotels were built there, and by the 1950s, development boomed dramatically and lasted almost 30 years. In the 1970s, ecological concerns about the island were raised, and laws were enacted to halt dredging of channels and filling in wetlands.

A hurricane opened the Ocean City Inlet in 1933 (the inlet separates Fenwick Island from Assateague Island to the south). To keep the channel navigable to the mainland, the U.S. Army Corps of Engineers constructed two rock jetties. Although the jetties stabilized the inlet, they altered the normal north-to-south sand transport by the longshore currents. The result is that sand built up behind the north jetty and the sand below the south jetty was quickly eroded. The accelerated erosion has shifted Assateague Island almost one-half mile (.8 km) inland. In a very short time, human interventions have permanently altered the barrier island profile.

Changes in Assateague Island as a result of accelerated erosion from the man-made rock jetties of Ocean City Inlet (top: photo of the inlet, bottom: map of the area with outline showing the position of the island in 1849).

Photo courtesy USGS

Changes in Assateague Island as a result of accelerated erosion from the man-made rock jetties of Ocean City Inlet (top: photo of the inlet, bottom: map of the area with outline showing the position of the island in 1849).

Photo courtesy USGS

Topsail Island, North Carolina

Topsail Island is a popular beach vacation spot along the North Carolina coast. This barrier island was extensively developed for tourism with the construction of condominiums and beach houses. In September 1996, Hurricane Fran made landfall near Wilmington, NC. The counterclockwise air circulation around the hurricane's eye caused heavy wave action and storm surges over Topsail Island. The storm eroded much of the island, causing overwashes. Several places on the island were eroded, and the island's only highway was seriously damaged. Residential homes were destroyed, and property damage was several-hundred-million dollars.

Hurricane Fran damaged Topsail Island in 1996 (top: before, bottom: after). Note how the overwash damaged the road and even broke through the island in places.

Photos courtesy USGS Photos courtesy USGS

Hurricane Fran damaged Topsail Island in 1996 (top: before, bottom: after). Note how the overwash damaged the road and even broke through the island in places.

Photos courtesy USGS Photos courtesy USGS

Hurricane Fran damaged Topsail Island in 1996 (top: before, bottom: after). Note how the overwash damaged the road and even broke through the island in places.

Photos courtesy USGS Photos courtesy USGS

Hurricane Fran damaged Topsail Island in 1996 (top: before, bottom: after). Note how the overwash damaged the road and even broke through the island in places.

Photos courtesy USGS Photos courtesy USGS

Although barrier-island development is a risky business, these islands continue to be popular vacation and recreational attractions. Because barrier islands serve important functions (protecting the coasts from storm damage, nurturing ecosystems and protecting wildlife), a balance is needed between conservation and further development.

For more information on barrier islands, check out the links on the next page.