Coastal Dune Lakes of South Walton

What is a dune lake?

It is a lake formed by wind. The larger category is “Aeolian lake” which is defined as “a lake formed by wind activity in arid regions, which may erode rock or redistribute sand forming dune lakes.” Most of these coastal dune lakes in South Walton are “mesotrophic,” which means they have moderate levels of algae and plant production. They contain beach and dune sand with silty sand, silt and many different formations of clay. They are unusually shallow, averaging about 5 feet, and were formed between 2,000 and 10,000 years ago. They are generally permanent water bodies, although water levels may fluctuate substantially due to rain, groundwater seepage through the surrounding coastal sands, and storms. Sand dunes ranging in height from a few to more than 30 feet separate the lakes from the gulf.

Where are they found?

Coastal dune lakes are rare worldwide. In the U.S., they are almost exclusively found along the Gulf Coast.

What makes a Coastal Dune Lake so Unique? 

The lakes often have passes that open to the Gulf, which allow salt water and fresh water to continually exchange and flush out the lakes, creating some of the most distinct ecosystems in the world, according to Lakewatch Director Julie Terrell. They are characterized by the intermittent nature of this connection to the Gulf. When the water level, through rain or other inflow, reaches a certain critical height, the lake will “blow out” and release its water into the gulf. At that point, seawater may enter to create an estuary.

After the lake water level subsides, the connection to the Gulf will disappear until the lake is ready to discharge once more. The outfall (inlet) areas are part of the dynamic ever-changing coastal environment. These areas are not stable and are continually subjected to storm and wave over wash and shifting sands. The fact that they share salt water and fresh water is what separates these lakes from all others, according to Harold Mitchell, an environmental specialist at the Department of Environmental Protection.

Because of the changing nature of the water, these lakes are known to be biologically diverse with many different marine species. They are also an important source of freshwater to migrating birds and other beach organisms. Wise use and management of coastal dune lakes and their connection to the sea is important to the integrity of the coastal ecosystem, according to Gail Carmody, Field Supervisor with the Fish and Wildlife Service.

How many do we have in South Walton and what are their names? Where can we see them?

They are seen along Scenic Highway 30-A and there are 15 named Coastal Dune Lakes. Their names are:

Inlet Beach · Camp Helen · Lake Powell · Camp Creek Lake · Deer Lake · Eastern Lake · Western Lake · Alligator Lake · Little Redfish Lake · Big Redfish Lake · Draper Lake · Oyster Lake · Allen Lake · Stallworth Lake · Campbell Lake · Morris Lake · Fuller Lake



Coastal Dune Lake on 30-A


Coastal Dune Lake in South Walton, FL


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