City of St. Augustine’s sunny day flooding fix moves ahead

Flooding in St. Augustine’s Davis Shores neighborhood could soon be minimized thanks to a new stormwater system.

 

After securing approval for a cost-share program, the city ordered valves for stormwater outfall pipes to get rid of sunny day flooding in Davis Shores, the kind of flooding that comes not from rain but from high tides.

“That’s the idea of these backflow preventers is to keep those nuisance tides from coming back up through the stormwater system,” St. Augustine Public Works Director Martha Graham recently told St. Augustine commissioners.

The city is expected to spend $591,000 on construction and receive up to $195,030 in reimbursements from the St. Johns River Water Management District, according to Jessica Beach, city project manager and professional engineer. The district awarded funds to St. Augustine in part because of the large area the project will help and because the project meets a district goal of flood prevention, said Derek Busby, district project manager.

Stormwater in the city goes through pipes to destinations including the Matanzas River and Salt Run, according to Beach.

The valves should help residents see fewer flooding incidents over the course of the year. Sunny day flooding happens about 12 to 16 times a year in St. Augustine, according to the city’s agreement with the water management district.

The city will create a schedule for when and where the 17 valves will be installed, and more details on how they work, Beach said.

Basically the valve adds a flap or membrane that stays shut against water that would back up into a stormwater pipe — but it will open for water flowing out of the system if there’s not water from a high tide blocking the other side of the valve, Beach said. So the valves won’t prevent flooding when there’s high tide combined with heavy rains.

The city’s installing valves from two manufacturers, Beach said. The valves are slightly different, such as in weight and how they fit, but function similarly, she said.

Seven valves will go to North Davis Shores, and 10 will go to South Davis Shores, including two connected to a ditch off Coquina Avenue, Beach said.

The cost share funding wasn’t available until Oct. 1, so the city ordered valves last week, Beach said. While the deadline to get them installed isn’t until Sept. 30, 2018, under the cost-share agreement, Beach said the city expects to be installing them by January. The rest of the valves should be ordered soon, she said.

 

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