By Terry Witt – Spotlight Senior Reporter
A senior project engineer for Wright-Pierce told Williston City Council members Tuesday that the June 20th flooding of multiple streets was caused by a 25-year storm or possibly stronger and the only cure for what went wrong is federal grant money.
Walt Nickel said Williston was hit hard by rain on June 16, 17 and even harder on June 20th when 5.1 inches of rain fell in a four-hour period as measured at a Southwest Florida Water Management District (Swiftmud) weather station a mile-and-a-half north of town.
“You had saturated ground already, then pretty hard rainfall came through on the 20th,” he said.
Nickel said Williston residents reported receiving 6-10 inches of rain in a 6-hour period on the same day. Though the totals aren’t official, he said Doppler Radar, which can accurately determine the severity of rainfall, indicated there were heavier cells coming south of the Swiftmud gauge.
“From an engineering standpoint, it’s not data we can go to, but if that happened in 6 hours, there’s evidence from the rain gauge data that it was about a 25-year storm event, which is what your stormwater ponds and stormwater systems are designed to handle. So, if you have a new residential development with a stormwater pond, that’s about the limit, and if there was 10 inches as reported, it would be overwhelmed.”
Nickel said those numbers and scientific data put the flooding in perspective.
“You got hit hard. Nobody wants flooding, but there is a level of design you can only afford to do and it was exceeded in a lot of these areas,” Nickel said. “But that’s not to say we’re not looking at things we can do.”
John Henry Park Flooding
One of the locations that experienced heavy flooding was at John Henry Park. He said the city got one grant that was enough to construct what was needed for flood control at the park, but an additional resiliency grant was received in the spring for the same area. He said the city is waiting for the paperwork to arrive on the resiliency grant. Olerich Construction, Inc. will do the work.
“That will take care of a lot of what happened to John Henry Park, the nursing home, and the Joab Penny area. It’s all tied into that. We should see some improvements,” Nickel said.
Country Lane Estates Flooding
Nickel said his company and city officials also looked at flooding on NW 7th or Country Lane Estates, a new subdivision under development. He said his company had done some earlier sketches and design ideas to help some parts of that area.
“There was predicted flooding in that area,” he said.
He added that the Federal Emergency Management Agency (FEMA) is expected to offer Building Resilient Infrastructure and Communities (BRIC) grants in September that help communities avoid the type of flooding problems the city experienced on June 20.
“It could be used in communities like Williston for flooding issues and problems,” he said. “We’re going to keep an eye on that grant and there may be some opportunities that would help there and some of the other areas you had flooding.”
Nickel said the area known as Cottage Grove in the area of 7th St. and NW 5th got “severely hit” by flooding on June 20.
“That’s in a low bowl almost. We could look for that BRIC funding to see if that would be available to that area,” he said.
He added that SE 1st Ave. and SW 1st Av. had flooding. He said the city is also looking at the flooding in that area.
Camelia Plantation Stormwater Issues
“Are you looking at Camelia Plantation?” said Council President Debra Jones.
Nickel said they looked at Camelia Plantation.
“That is one I would say from our observation, it did what it was supposed to do for the storm. It did seem to drain very slowly, slower than it should,” he said.
Nickel said he went to the site several times after the flooding and may want to recommend to staff a course of action that he has already discussed with Public Works Director Jonathen Bishop. He said there may be percolation problems with the stormwater retention pond, and testing is needed. He said the retention pond has been well maintained but silt and sediment may be preventing water from percolating down as fast, “but there might be some easy things that can be done there,” Nickel said.
He added that there were issues with water that couldn’t get out of Camellia Plantation. There were issues downstream that caused problems and backed up stormwater into the subdivision.
“It was unfortunate but it was at its design capacity, but there might be some easy things that could be done there,” Nickel added.
He said staff looked at all the flooding sites in the city.
“Everything needs money, so we’re looking at the grant opportunities to see if there’s something we can do,” Nickel said.
“Sounds like a plan,” Jones responded.
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City of Williston Regular Meeting July 18, 2023; Posted July 19, 2023
