Lakefront Berms and Swales


As more and more development occurs around Johns Lake, it is imperative that residents understand that we can have a significant effect on water quality. If we want to minimize hydrilla infestation, other invasive plants, algae blooms and pollution, we need to adhere to a few simple guidelines that will help immensely. This includes the proper use of berms and swales.


“A berm and swale is a low hill and associated depression incorporated into the landscape, typically parallel to the shoreline. This area slows and captures runoff and allows water and pollutants to percolate into the ground. This prevents pollutants and excess nutrients from entering the lake from your yard.”

Shown below is a fairly typical depiction of a berm and swale configuration:

Typical Berm and Swale on Johns Lake

Here are some of the main benefits of the “berm and swale” system:

  • Provide a drainage path for rain and storm water runoff
  • Act as a filter between the water and chemicals that have detrimental effects on the lake (e.g. fertilizer, pesticides, etc.)
  • Provide a buffer between the lake and residential/commercial sites that have septic tanks or other potential pollutants, even drainage from swimming pools.

In order to preserve the water quality of Johns Lake we need to be responsible. Homeowners should feel a responsibility to the environment to do their part to keep the lake as pristine as possible. There are really only a few precautions and actions needed to accomplish this:


Reduce Chemicals. Minimize herbicide, pesticide and fertilizer use. Never apply these chemicals before heavy rains. Spread mulch to prevent weeds and erosion. Identify pests before spraying and use the least-toxic pesticide available. Follow label directions for all pesticide, herbicides, and fertilizers.

Manage Yard Waste. Never blow lawn clippings into streets, lakes, or storm drains. Use leaves and pine needles as mulch. Compost yard waste and kitchen scraps. Pick up trash, litter and pet waste.

Conserve Water. Plant native or Florida-friendly plants. Turn off irrigation systems during the rainy season (June 1 – Sept. 30) or make sure your rain gauge is working properly. Install a moisture sensor on old irrigation systems, or make sure your sensors are working correctly. Direct sprinkler heads toward the landscape, away from pavement. Inspect sprinkler heads often and repair when needed.

Obtain Permits. If you plan to change anything on your lakefront like removing or planting vegetation or changing some aspect of the berm or swale, permitting will ensure it’s done properly and within guidelines. It only requires filling out a form and paying a small fee and it is the proper way to conserve our water quality.


Modify a Berm or Swale. Lakefront home owners should never fill in a swale and remove or relocate a berm. These features are not designed for individual properties, in nearly all cases, berms and swales are tied into adjacent properties, sometimes through whole subdivisions and for miles in some instances. Any changes made to them can negatively affect other berms and pollute the lake. Also, modifying the berm can start the process of erosion which will eventually make the berm ineffective.

Dump Chemicals in Berm or Swale. Do not dump anything hazardous into the vicinity of the berm system since this defeats its purpose. Automotive fluids, petroleum products and even drainage from a swimming pool are harmful. You should drain swimming pools slowly, on your land, and not into the berm and swale system or anywhere near the lake.

Plant Any Unapproved Vegetation in Berm or Swale. The lakeside of the berm is very important and presents the “filtered” side of runoff and drainage to the lake. Planting anything on that side of the berm that requires fertilizer or pesticide should be avoided and completely defeats the purpose of the berm and swale feature.

Never Place Anything in the Swale Do not put yard waste trash, clippings or leaves in the swale. This impedes storm water runoff and increases the amount of pollutants that would flow into the lake.

Additional Information

The berm and swale system are actually living ecosystems. As water is directed into the feature, micro-organisms thrive and support vegetation which make the berm largely self-maintaining and create a water reservoir in the system.

Berm & Swale Ecosystem

It may be alarming to see standing water in the swale at times (particularly after heavy rains), but this is how it is designed. The swale collects water and temporarily holds it so that any pollutants, sediments, etc. will take longer to be processed by the vegetation and soil. Water may pond in the swale for 24 to 36 hours. This is perfectly normal gives the swale more time to percolate and cleanse the runoff.


The picture below is a good illustration of good practices in maintaining the quality and function of a berm and swale system. No fertilizers or pesticides should be used on the lake side of the berm and eco-friendly vegetation should be maintained along the shoreline. 

Protected Berm & Swale areas

Older subdivisions around Johns Lake have street-side storm water drains and retention ponds that drain directly into Johns Lake. The same precautions should be used for these features as well.

Subdivisions developed after 1985 have storm water permits with SJWMD which establish an obligation to maintain the berms and swales and ensure their proper function. So, HOAs (Homeowner’s Associations) and homeowners have a duty beyond just “good practices” to keep these important features intact and unspoiled…

Sadly, some lakefront property owners are unaware of, or just disregard, the environmental standards that are the reasons behind the berms and swales. There have been instances where residents have tried to backfill the swales and/or remove the berms, or, relocate them. 

If homeowner’s have any questions about regulations concerning permitting or maintaining their lakefront berms and swales they can contact 

SJWMD (Saint John’s Water Management District) Customer Service during business hours at: 


Together, we can maintain the high quality of life we now enjoy!