Coastal Dune Lakes

Coastal Dune Lakes of South Walton County 

Coastal Dune Lake Facts

Dune lakes occur in only a few places around the world, but 15 are found along the white beaches of SoWal!
Lakes create an opening (outfall) to the Gulf of Mexico during periods of high water levels, causing fresh and salt water to mix.
Temporary estuaries and nursery grounds are formed when the fresh and saltwater mix.
Each lake is different due to variable salt content, dependent upon frequency of outfall openings.
Conservation efforts are ongoing to protect the health and longevity of these special ecosystems.

Please Help Protect!
Stay on marked trails and boardwalks - keep off dunes and vegetation.
Be sensitive to natural processes, do not dig in or around the lake outfalls.
The health and beauty of these lakes is very important, properly dispose of all trash.
Follow all fishing regulations.
Beware of Alligators!
Use no boats with motors.
Leave no items on the beach overnight.  

Perhaps the most unique and precious features of South Walton are the coastal dune lakes found in the area’s beach dune system. The rare lakes are reportedly found only along the coasts of New Zealand, Australia, Madagascar, and in the United States along the coasts of Oregon, South Carolina, and Northwest Florida.

One of the most interesting features of Soouth Walton's coastal dune lakes is their intermittent connection to the Gulf of Mexico. When a lake reaches a high water level, it breaks through the dune system and beach and empties into the Gulf of Mexico. The channel that forms between the lake and the Gulf is known as an outfall. Depending on tides and wind, saltwater from the Gulf may enter the lake, along with saltwater plants and animals. 

The drainage of the lake and potential exchange with the Gulf continues until equilibrium is reached and the opening closes. Some visitors wonder whether the brown water in the outfalls is sanitary. The water in the lakes is dark brown or tea-colored with natural tannins from leaves falling into the lake, and is not harmful. 

Coastal dune lakes develop from various coastal processes, most commonly when sand deposition fills an inlet to a tidal basin or lagoon. Once isolated from the direct effects of tides, the water may become hypersaline because of salt water intrusion through sandy substrates and rapid evaporation of surface water. Lake water may also gradually become less saline if there is a decline in subsurface saltwater intrusion and greater freshwater inputs from rain and watershed drainage. 

Source:  http://sowal.com/coastal-dune-lakes-of-south-walton-county

Published on Friday, May 6, 2016