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In the Coastal Dune Lakes

What is a Coastal Dune?

Coastal dune lakes are bodies of water found in dune ecosystems within two miles of the coast.

They’re typically shallow and irregularly shaped. Coastal dune lakes are usually permanent water bodies, but their water levels fluctuate substantially since they create transitory interchanges with the Gulf. The lake water is composed of both fresh and saltwater that comes from tributaries, groundwater seepage (from uplands and from the Gulf), rainfall, exchange with the Gulf, and coastal storm surges. The lake water is generally colored (e.g., tea or black colored) due to the dissolved organic matter it contains. This is a natural phenomenon, and it’s nothing to be worried about! While these lakes are exposed to normal weather conditions just like any lake, Florida’s coastal dune lakes are also tremendously impacted by hurricane activity (i.e., storm frequency, strength, and duration).

Interesting Features

One of the most interesting features of Walton County’s coastal dune lakes is their intermittent connection to the Gulf. When a coastal dune lake reaches a relatively high water level, it actually breaks through the dune system and the beach sand and empties into the Gulf. The channel that is formed between the lake and the Gulf is known as the lake’s outlet or outfall. Depending on tides and weather conditions (particularly 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 continue until equilibrium is reached and the opening closes.

Individual Personalities

Each of Walton County’s coastal dune lakes has its own personality, based on the combination of its size, watershed features, surrounding land uses, and outlet characteristics. Outlet openings vary greatly in length, frequency, and duration. They are driven by each lake’s critical high water level as well as prevailing climatic conditions (e.g., droughts and rain). As a result, some of the dune lakes can be completely freshwater, some brackish, and some salty, with varying degrees of salinity occurring between different lake stages. The changing condition of water chemistry in the coastal dune lakes makes them dynamic, biologically diverse ecosystems.

Accessing the Lakes

Consult the document posted by Walton County to see a list of public access points.

CBA & the Coastal Dune Lakes

Walton County’s coastal dune lakes are a visual trademark of the southern end of the county and a source of great pride among citizens. They are unique ecosystems marked by their dark, brackish water and intermittent opening to the Gulf of America. The Choctawhatchee Basin Alliance has partnered with Walton County and other concerned citizens and organizations for two decades to monitor, investigate, restore, and educate people about the coastal dune lake systems.

Management Plan

Notably, CBA orchestrated the development and publication of A Management Plan for Walton County’s Coastal Dune Lakes (October 2008). This document is the product of a two-year process involving several rounds of citizen and stakeholder input; it was promptly adopted by the Board of County Commissioners. We are proud that this document represents a truly collaborative effort and contains the best science on the coastal dune lakes. It is a comprehensive living document that can guide and advance the conversation among citizens and decision-makers when it comes to land management surrounding the coastal dune lakes.

Monitoring

CBA manages a volunteer water sampling program in cooperation with Florida LAKEWATCH, whereby citizen-scientists collect monthly nutrient, chlorophyll, water clarity, and water chemistry data on the lakes. We have more than a decade’s worth of monthly data on most lakes. Explore our website to learn more about CBA’s Water Quality Monitoring Program. Data is available to the public upon request.

Research

CBA has commissioned scientific studies on the coastal dune lakes and provided field assistance for these projects. With CBA’s assistance, the University of Florida’s Florida LAKEWATCH program has created bathymetric maps and completed plant surveys on several of the coastal dune lakes. In addition, Dr. James Jawitz, UF Soil and Water Science Department, completed an initial hydrologic study and continues to collect data on Campbell, Draper, and Camp Creek lakes.

Reports of these research activities can be found on our Coastal Dune Lakes Research & Publications page. As of yet, fish identification data is very limited on the lakes and has the potential to provide valuable supporting information for further conservation of such systems. Each study supports the others, together seeking to provide a comprehensive understanding of the functioning and importance of the local coastal dune lakes. Many of CBA’s coastal dune lake research endeavors have been undertaken jointly with the Mattie Kelly Environmental Institute.

Restoration

CBA’s primary restoration activity on the coastal dune lakes is the identification and control of exotic and invasive plant species, followed by revegetation with native species. On Oyster Lake, CBA was part of a large-scale restoration project that allowed for two roads to be removed from the lake and replaced with bridges. CBA conducted water quality monitoring and coordinated a sediment study, exotic plant control, and re-vegetation with native plants prior to this work. We coordinated the design & installation of educational signage on-site and post-project water quality and sediment analysis following the final phase of the project. Funding for this project came from Three Rivers R&CD, a Five-Star Restoration Grant, and the USFWS.

Education

CBA works in both formal and informal settings to educate citizens about the coastal dune lakes of Walton County. As part of our restoration work, students from South Walton High School (SWHS), Collegiate High School of Northwest Florida State College, and the 4H program, as well as teachers from Bay and Butler elementary schools have helped us map exotic and invasive plant species on the lakes. SWHS students planted several hundred plants to restore the shoreline of Oyster Lake. AmeriCorps members and students from the University of West Florida have worked with us to maintain our water quality monitoring program on the lakes.

In addition to this work with local schools, CBA educates citizens through participation in local festivals and public workshops. We also work with the county extension service (UF/IFAS) in creating educational materials and distributing information.

Research & Publications

Basic Educational Information
Press
Water Chemistry
Hydrology