Barrier Islands
Barrier islands are long, narrow, offshore deposits of sand or sediments that parallel the coast line. Some barrier islands can extend for 100 miles or more. The islands are separated from the mainland by a shallow sound, bay or lagoon. Barrier islands are often found in chains along the coast line and are separated from each other by narrow tidal inlets, like the South Lake Worth Lagoon (Boynton) Inlet.
Barrier islands are nature's way of protecting the mainland. Ideally, these islands should not be inhabitated or developed. This is unrealistic given man's desire to live by the water and long ago established communitities.
Knowledge about and respect for barrier island's unique environment, animal and plant habitat and natural occurences is crucial for co-existence and preservation.
Barrier Island Habitats
- Beach & Dunes - Animals and plants in this environment must endure long periods of exposure to salt water and drying air.
The animals on the beach itself include many varieties of crabs and turtles, clams, burrowing
worms, and various shorebirds such as sandpipers, seagulls and pelicans.
Along the dunes, you will find many crabs and birds such as gulls and terns. Natural habitat include seagrape, sea oats, bunch and beach grass. - Intracoastal Waterways - The Intracoastal Waterway is a 4,800-km (3,000-mile) recreational and commercial waterway along
the Atlantic and Gulf coasts of the United States. The waterway runs the length of the Eastern Seaboard (Maine to Miami, Florida).
Palm Beach County's Intracoastal Waterway (ICW) is 43 miles long: 30 of the miles were natural waterways and 13 miles were manmade. The South Lake Worth Lagoon accounts for 20 miles in the overall 43 mile calculation. The ICW is 10-12 feet deep and 125 feet wide.
Natural vegetation includes mangroves and threatened Johnson's seagrass. Animals that live in the intracoastal waterways include manatees, fish, turtles, porpoises, and various birds, egrets, pelicans, and stilts.
Nature's Effects on Barrier Islands
Regardless of the scope or type of developments on the barrier islands, nature has a way of ensuring that this land is ever changing. Understanding the nautral dynamics is critical for planning and development purposes.- Waves & Currents - Waves continually deposit and remove sediments from the ocean side of the island.
Longshore currents that are caused by waves hitting the island at an angle can move the sand from one end of the island to another. This natural occurence cyclically deposits and removes sands creating an ever changing landscape. - Winds - Winds blow sediments from the beaches to help form dunes and into the marshes, which contributes to their build-up.
- Sea level changes - Rising sea levels tend to push barrier islands toward the mainland. According to the Miami Dade Climate Change Advisory Task Force, a three to five foot rise in sea level is expected this century. Obviously, low level coastal areas on the barrier island are at risk. Click here to read an excerpt from the report "Preparing for a Sea Change in Florida" by the Florida Coastal and Ocean Coalition.
- Storms - Hurricanes and other storms have the most dramatic effects on barrier islands by creating overwash areas and eroding beaches as well as other portions of barrier islands.