By Kathy Danforth / Published May 2017
Associations in Florida frequently enjoy bodies of water or wetland areas on their property, and residents may think these natural habitats will take care of themselves. Particularly in South Florida, this laissez-faire environmental approach may result in the conversion of a seemingly innocent pond into a money pit.
A major reason why lake health is a concern, according to Adam Grayson with Lake and Wetland Management, is because they are serving a purpose beyond aesthetics. “In South Florida, especia-lly, these water bodies are usually stormwater retention ponds created to hold an adequate volume of water from heavy rains and also to catch impurities. When plants or sediment take up space, the pond may no longer be able to hold and filter water adequately,” he advises.
“In this sub-tropical climate, many invasive species thrive,” he explains. “Some, such as hydrilla, came from aquariums, but they have no natural controls in this environment. Common plants that reproduce so fast that they overwhelm the competition are water lettuce, water hyacinth, torpedograss, alligatorweed, water primrose, and hygrophila. They grow rapidly and take up space in the lake, and then when there is a large storm, lakes may flood.”
Invasive species are transferred to bodies of water by birds, alligators, and other wildlife. People inadvertently introduce problems when they fish in an infested area and transfer plant material elsewhere on their boats, fishing lures, boots, etc.
“There are added problems if you ignore the issue, so the buzzword right now is ‘EDRR’: Early Detection, Rapid Response,” according to Grayson. “Since these plants are part of an interrelated biological system, you can’t take a large amount of plant material out with one shot. Herbicide treatment is systemic and will kill the root system, but if you treat too much, the dissolved oxygen in the water is reduced, which can kill fish. However, when only utilizing manual harvesting the plants will return, as the root system is not completely removed. In the summer, these species may grow as much as an inch a day.
“Only herbicides labeled for aquatic use can be applied in water in Florida,” notes Grayson. “The chemicals must be applied by a licensed applicator following all labeled instructions. Though some of the same chemicals may be used for land applications, the formulation will be different, usually with surfactants to help target the appropriate plants.
“Since nature abhors a void, native species are often introduced to help prevent and combat invasive plants,” comments Grayson. “Eelgrass, chara, pickerelweed, arrowhead, swamp lily, and iris are good choices to replace invasive exotic plants. A biological control species like grass carp will eat the hydrilla, but if you have too many of them, they will eat the good plants also.”
Excessive algae can be another sign of an unhealthy body of water. “When algae are out of control, they are unsightly, smell, and may have mosquitoes that accompany the stagnant water,” says Grayson. Also, when an algal bloom dies, the decomposition process will remove the oxygen from the water and may kill fish.
“Algae blooms are normally the culmination of excess nutrients in the water,” observes Grayson. “There has to be a balance with the native plants and their nutrient uptake. Since you can’t always pre-control algae, Best Management Practices (BMP) need to be used as much as possible for prevention.”
Landscape companies are on the front line in preventing excess nutrients from reaching water. Though the BMPs are different in every area, Grayson points out that no grass clippings should enter drains or water bodies, and fertilizer should not be applied within 25 feet of water.
“Depending on the age of the community, most storm drains will lead to the lakes on the property, which may be interconnected with only one or two exit points,” explains Grayson. This means that homeowner awareness of the impact of runoff can be critical for pond health. A portion of the spills, leaks, and chemical applications on a homeowner’s property will likely make their way to the lakes with normal rainfall and runoff.
Sediment build-up in lakes is another concern, with the same consequence as invasive plants: less space for water. Grayson states, “Sediment build-up happens naturally over time due to erosion and run-off. Lakes need to be monitored to make sure they maintain the capacity they were designed for. Natural agents such as bacteria and enzymes can consume muck on the bottom, but it can be costly.”
Erosion doesn’t just fill the ponds; it also removes desired land. “Property loss is a major concern, and at some locations, it can undermine structures,” says Grayson. “Even a gradual erosion of a slope can create a more hazardous situation.
“The first remediation step depends on the situation and the budget,” according to Grayson. “Plants similar to those used in wetland areas, such as muhly grass, are often used to stabilize a bank, but they don’t reclaim the area. Rip-rap and interlocking stones are sometimes used, with a seawall being the most expensive fix.”
“We can also dredge material from the lake and install a natural material over it,” Grayson reports. “This will encapsulate the edge and actually reclaim land.”
While fountains are primarily aesthetic, aerators can play a part in promoting a healthy lake. “Fountains make a beautiful display, but it’s just surface agitation so there’s not much biological benefit,” observes Grayson. “An aerator functions the same as one in a fish tank and stirs up the water column. Over time all lakes form layers or stratify. For lakes more than five feet deep, an aerator can increase dissolved oxygen further toward the bottom. This is mainly for fish and wildlife, to help stabilize dissolved oxygen levels and prevent fish kills. Where the aerator is sitting, muck will be pushed away as it creates an aerobic environment.”
Some communities may wish to attract wildlife; Grayson suggests bird boxes or the addition of fish habitat materials for those wishing to encourage those populations.
“The state has a lot of rules covering lakes and wetlands, and counties can be even more restrictive,” cautions Grayson. “Wetland areas receive their designation from the state based on the soil and the plant types. Always check with the local authorities for their rules and restrictions before taking actions affecting either wetlands or bodies of water.”
“The biggest mistake communities make is not paying attention to the condition of their lakes,” states Grayson. “You want to reach out to a licensed professional before anything becomes a big issue. We see communities who delayed in order to save money, but in the long run it costs them more.”
For more information on Lake & Wetland Management, call (855) 888-LAKE or visit www.lakeandwetland.com.