Naples Botanical Garden creates floral swale for parking lot runoff

Naples Botanical Garden is doing its part to help clean up our waterways by making a massive swale filled with plant life for filtering parking lot runoff.

“We’ve got algal blooms, red tide, and blue-green algal blooms; those tie back to how we manage our landscapes and reducing nutrients going through the systems out to the Gulf, and we can do that through plants,” said Chad Washburn, vice president of conservation at Naples Botanical Garden. “We had an opportunity to take on some freshwater from an off-site project and ensure that that water gets treated before it goes back to our natural systems.”

The botanical garden is planting native flora 3,500 times across the winding, sloping channel. The plants will slow water that would have otherwise poured off a parking lot and eventually reach the Gulf of Mexico, rich in nutrients to encourage algal growth.

“Things like phosphorus and nitrogen, which are definitely present on roadsides from fertilizer being used, that ends up being going into the ocean,” said Eric Foht, natural resource director for Naples Botanical Garden. “It’s been shown that those types of fertilizers and nutrients can accelerate naturally occurring algae.”

This creation mimics a natural ecosystem, absorbing water and naturally filtering it to avoid propagating red tide and blue-green algae.

“What we really want is as much contact time with that water in this ecosystem,” Washburn said. “So, as it flows through those plants, we slow it down, we ensure that any pollutants that are in that water can either precipitate out, or they have time for uptake into the plants.

The plants in the swale are all collected on-site and are native to Southwest Florida’s ecosystem.

“They’ll survive cycles of drought and flooding; we don’t need to add irrigation, we don’t need to add fertilizer,” Washburn said. “This is something that really, we need to do across the community. We have significant stormwater systems, stormwater ponds—many of us have stormwater ponds in our backyards, and those can be more efficient at filtering water.”

The longer water’s in the swale, the cleaner it is once it gets to the coast. “It’s going to filter through all of these plant materials and into our own lake system, which is a whole nother process, and then finally to the bay,” said Jessica DeYoung, conservation horticulture manager.

“So anytime we do a planting, we look to nature, we look to natural ecosystems. So with the swale, we look to an ecosystem like the Everglades that goes through cycles of heavy rains, where it’s gonna get flooding,” said Washburn.

A useful function considering the storms we see.

“When we get storm surge like that, it prevents a lot of that flooding from reaching the higher areas,” DeYoung said.

While the plants are no match for a “Hurricane Ian” storm surge, they will help with our typical summertime storms. In a month, the team will plant more up along the banks to better channel rainwater runoff.

If you have spots in your own yard where water collects, there are steps you can take to help. Planting around these areas, ideally using native plants, can create a buffer zone to keep pollutants like fertilizer or pesticides out of the water.