- March 12, 2025
Bird of Paradise was under water. Opposing rows of mailboxes stood in the murky surface. The sky was eerily calm an hour after an intense rainstorm drenched parts of the city in up to 5 inches of water, according to the National Weather Service.
The city’s swale system, which is used for stormwater draining, filled to capacity during a rainstorm Monday and overflowed, pushing ripples into the streets and causing flooding in some neighborhoods, particularly in the B- and R-Sections, late into the afternoon.
Nearby, on Burroughs Drive, Jessica Garcia watched her children play in the street — they called it a lake — riding their bikes off jumps into the inches of water and splashing each other. Aside from them and the occasional camera-wielding neighbor who ventured outside, the streets were empty.
“I’ve never seen that much water in my life,” Garcia said. “Things are fine if there’s a little rain, but God forbid, if there’s anything bigger, you aren’t going anywhere.”
The waterlogged streets prompted — or in some cases, revived — a question for some Palm Coast residents: Does the swale system really work?
A drainage system
When it storms, runoff water is collected in the swales that line the roads of the city. These artificial landforms slope at a slight gradient, seeping excess water from one house to the next, downward through the swales and, eventually, into a side ditch. From there, water typically runs into a canal or a natural body of water, such as a wetland, for filtration, and finally to the Intracoastal Waterway and into the ocean.
This system of drainage was adopted in Palm Coast in the 1970s and was built to withstand a 100-year storm, or a storm so severe it will likely only be seen once every 100 years, said John Moden, city engineer for Palm Coast. It also helps to revitalize the city’s aquifer, because soil acts as a natural filter in the ground.
“But what science has found is it’s worse to have three 30-year storms than one 100-year storm,” Moden said. “It takes the average drop of water about two weeks to get through the stormwater system, so the soil can be saturated from a previous storm when a new one hits.”
When that happens, a rainfall like what the city saw on Monday is more than the swales can handle.
“Monday, we had anywhere from 2 to 5 inches of rain within an hour and a half,” Moden said. “Our system is designed more for 12 inches over 24 hours.”
What’s problematic, Moden said, is determining the amount of water to prepare for. Conceptually, a swale system could be capable of withstanding a storm of any severity. But since swales work on such a slight gradient, they can only push water so fast.
The question, said Palm Coast City Councilman and former ITT employee Frank Meeker, is one of practicality.
“Why build something massive if you’re only going to use it every 100 years?” Meeker said. “There’s always the opportunity for a stormwater event that can come along and exceed the capacity for any system.”
For swale supporters, road flooding is to be expected on occasion.
“While most people look at the road as a way to get around, the reality is, it’s actually designed to be a part of our drainage system,” Meeker said. “Once the capacity of our swales is reached, the roads are our next line of defense.”
That's why the city mandates that houses be built at least one foot higher than the crown of a road.
“The good thing about this system is the water was gone so quickly,” Meeker said. “I’ve been places where a storm like that would have left water in the streets for days.”
Garcia said the “lake” in her front yard and the street outside her home were gone within two hours once the rain stopped falling.
“It was an inconvenience,” she said. “Nothing more, for now. They’re trying to make the drain system work, but I don’t know — I don’t know that it is.”
A leveled field
In 2004, Palm Coast was hit by three storms, bringing with them a lot of rain.
“The system didn’t have a chance to recover, and it was hit again and again and again,” Moden said. “That’s when our challenge arose: We need to maintain the system so it can operate to its standards.”
Soon after, the city started rehabilitation of its 1,000 miles of swales, which by then ranged from 30 to 40 years old. During those years, the swales had started filling in and no longer sloped at the right gradient, and the system was losing its effectiveness.
The city pinpointed 150 miles of swales that needed to be regraded and cleared from debris.
“We quickly recognized that it needs to be an ongoing program,” Moden said.
The city formed two crews dedicated only to swale maintenance. Each section is scheduled to be serviced twice each year. In October, the B- and L-Sections are attended to, and crews visit them again in April.
When crews turn their attention to a specific section, they address any open work orders and rehabilitate any swales that need rehabilitation. Often, the process involves simply regrading the swale and restoring the sod within it.
If a swale has major problems, the crew seeks the help of an engineer or takes more advanced rehabilitation steps. The city is currently working to remedy the flooding problems Bird of Paradise Drive has seen recently by connecting two canals on its south end.
Palm Coast will also soon start construction that addresses R-Section flooding, another area of the city that experienced water over roadways Monday. Remediation should start by the end of this year, Moden said, and will be completed by October 2013.
But swale rehabilitation is a process with no end date in sight. Together, the two crews can service up to 40 miles of swales each year, so working at maximum capacity, it would take the city 25 years to touch each one.
This continual maintenance is not common to cities with swale-based stormwater drainage systems, said Marty Wanielista, executive director of the college of engineering and computer science at the University of Central Florida and an affiliate of the university’s Stormwater Management Academy.
“Swales require a bit of maintenance, but it isn’t usually constant,” he said. “Putting sod in sounds unusual, but likely, you’re losing a lot of that sod in Palm Coast because the rest of the soil is so granular.”
Granular soil is more easily displaced, said Richard Adams, public utilities director for Palm Coast, and because of that, sod has been lost and the swales have begun to fill in, making them less effective.
“For us, rehabilitation never ends,” Adams said. “We concentrate on the worst-case situations because we just can’t do it all.”
Palm Coast’s stormwater budget is $7.5 million this year, which includes swale rehabilitation costs as well as expenses such as ditch repair.
To gutter or not to gutter
With constant rehabilitation efforts under way for Palm Coast’s stormwater drainage system, some argue that a new system is in order, like the curb and gutter systems found in other cities or in new developments within the city.
“Doing that would cost, I’m sure, hundreds of millions of dollars,” Adams said.
Moden said a curb and gutter system might not have the results its supporters hope for. Any system can be overburdened, he said, so whether it’s a swale system or a pipe system, if it’s not designed for the most extreme circumstances, there’s a chance the system will back up.
“Many new subdivisions are looking at swales because they’re more environmentally sound,” Moden said. “The grass is greener — literally — with a swale system.”
The swale drainage system is designed after swales that occur in nature. Because it lets water travel through soil rather than through pipes, the swales act as a filtration device for stormwater, separating the nitrogen found in rain water from the water that eventually makes it through the system.
“By the time any surface water reaches the aquifer, it’s completely naturally filtered,” Adams said. “It’s as if there were no development here at all.”
Filtering through the soil does not pose any environmental problems under normal conditions, Wanielista said.
“This type of filtration is sustainable in the sense that biological functions will eliminate anything left behind in the soil,” he said. “The ground takes care of that.”
The biologically focused filtration system has been praised by many, including the Environmental Protection Agency. But the EPA offers warnings against the system as well.
A swale drainage system is not very effective in a place that’s too flat, because maintaining a proper gradient in such a place is difficult, according to the EPA’s Storm Water Fact Sheet. Similarly, the swales are ineffective in places with erosive soils, the EPA says, because they can erode when water flow is too great.
And pollutants more severe than what’s naturally found in urban rainfall can be carried through into the groundwater under this system, the EPA says. The standing water in swales and their associated ditches can also become odorous, present drowning dangers, or breed mosquitoes.
But to change to a different system would be costly and perhaps fruitless.
“The same problems we have with swales — that flood in freak rain storms — are present with gutter systems,” Meeker said.
The city could switch, he said, but at great cost and with little change.
“We can design a system for any storm we want,” Meeker said. “But we have to ask what’s most cost-effective. There’s always going to be a storm that can devastate any system. That’s why they say it: 'Don’t test Mother Nature.'”
