Stormwater ponds are ubiquitous across Sarasota County and Southwest Florida. These features, when managed appropriately, can add great aesthetic value to a community. When improperly managed, however, these features can become a common source of resident concern and complaints. A proper understanding of what these ponds are, and how they are intended to function, is a critical first step in their management. The “Lakeside Living for South Florida Residents” installment of the Sarasota County Starter Kit Series laid the foundation of this understanding. Below are some key takeaway points from the webinar.

Stormwater ponds

Your neighborhood is likely home to a pond where residents enjoy watching the birds and turtles. Many residents and community managers mistake these water features for natural lakes.  These ponds, however, are stormwater ponds. A stormwater pond may not sound as glamourous as a “lake,” but stormwater ponds are an important and necessary part of your community. These ponds are pieces of stormwater infrastructure built with purpose.

Flood mitigation and water treatment

The primary function of stormwater ponds is to provide a level of flood mitigation for the surrounding community. Stormwater ponds serve as catchment and detainment areas for stormwater runoff, the water than runs across hard surfaces like streets and driveways during rain events. Runoff enters storm drains where it then moves to your community pond.

The secondary role of stormwater ponds is to allow for water quality improvement before runoff moves downstream. As runoff travels across streets and sidewalks it can pick up any number of pollutants along the way. These pollutants may include fertilizers, vegetative debris, metallic break dust, silt and soil, or even pet waste. Your stormwater pond is an area that provides a degree of natural cleansing for this water. As the water resides in the stormwater pond, some pollutants may begin to settle out of the water while others may be removed by some natural biological and microbial actions. This is important because the water in your pond will eventually, through one way or another, head on downstream. Our water is all connected, so the water in your pond may eventually become the same water in our local streams and bays.

Reduce runoff pollution

There are many things that we as residents can do to minimize pollutants being carried from our properties by stormwater runoff.

• Excess fertilizer from our landscapes can contribute nutrient pollution to stormwater runoff. The nutrients that feed our turf and plants are the same nutrients that can feed the naturally occurring algae in our surface waters. Be sure to fertilize appropriately, only using the minimum required amount and always following the product’s label. Sarasota County has a fertilizer restriction season from June through September where the application of nitrogen-containing fertilizer is prohibited. If you choose to fertilize during the rest of the year, ensure that you choose a product that derives at least 50% of it’s nitrogen content from “slow release” or “insoluble” sources. This will be listed on the back label.
• Pet waste from our yards and surrounding areas can contribute not only nutrients but pathogens to stormwater runoff. Be sure to always pick up after your pet.
• Grass clippings can contain nutrients and should never be allowed to remain on hard surfaces like sidewalks and streets. Grass clippings should never be left near a storm drain or intentionally blown into storm drains or ponds.
• Excess irrigation or irrigation that sprays onto hard surfaces can contribute to runoff. This is of particular importance to those who utilize reclaimed water for irrigation as a water conservation measure. Reclaimed water is an incredible tool for lowering our water consumption, but reclaimed water contains residual nutrients like nitrogen and phosphorus. It is important not to spray reclaimed water onto hard surfaces like streets or sidewalks where it can contribute to runoff.

Littoral zones

The littoral zone of a pond is the shallow sloped area around the inside perimeter of the pond that is typically a depth of 5 feet or less. This area allows for the growth of native aquatic emergent vegetation such as pickerelweed, duck potato, gulf spikerush, and golden canna. Emergent plants may play an important role in the overall function and stability of your pond. Emergent plants can help protect your pond’s banks from the gentle wave action of the pond’s surface. This wave action may look like only small ripples, but over the years these ripples can contribute to costly and unsightly bank erosion. Emergent plants help to block and deflect these ripples before they contact the banks. Aquatic emergent plants may also aid in the uptake of nutrients, provide habitat for wildlife like turtles and wading birds, and help hide small amounts of floating algae from sight.

Buffer zones

Buffer zones are areas meant to separate the water from the land and reduce external pressures on the water. External pressures can refer to things like fertilizer or pesticide application and mowing. Buffer zones consist of taller plants along the bankside perimeter of the pond. Tall plants such as native bunch grasses can produce deeper and more complex root structures than short-mowed turf. These deep root structures can help stabilize soil, and help hold in in place against erosion. Additionally, the presence of tall unmowed plants around the pond’s banks can help keep heavy mowing equipment away from pond banks which may be saturated, eroded, or otherwise structurally compromised. Buffer zones can be done in a verity of ways. The most common ways to provide a pond buffer are through the installation of native landscaping plants or the installation of a “no-mow zone,” which allows the existing turf to grow and be maintained at a height of about 8-12 inches. Whichever buffer method your community chooses, it is important to remember that buffer zones are NOT “maintenance-free zones.” No landscape feature is maintenance free. Regular maintenance will be required to keep weeds and invasives out of the buffer zone and to maintain plants at the appropriate height. When done properly, a buffer zone of native bunch grasses, short shrubs, and wildflowers can be a stunning landscape feature to be enjoyed by the whole community.

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