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Reduction of “sunny day flooding” on the rise

As part of cost share funding from the St. Johns River Water Management District, the City of St. Augustine has begun the process of retrofitting existing storm pipe outfalls with new “tide check” valves throughout Davis Shores.

flooding001In its history, damage caused by flooding has greatly affected the city, specifically the low-lying areas of Davis Shores. Whether from catastrophic hurricanes, sea level rise or sunny day flooding, this ever present concern has been a priority for the longevity of the city, its residents, visitors and infrastructure. 

During sunny day, temporary tidal flooding events, sea water enters the city’s stormwater drainage system, backing up and into the streets, creating street flooding. In the Davis Shores community there are approximately 21 outfalls that collect the stormwater from the streets and discharge through the existing pipe system into either the Matanzas River or Salt Run. As of November 20, eight valves have been installed.

But the valves have limitations. If rainfall occurs during a high tide event, where the valves are shut, the rainwater will not be able to drain until the tide falls leaving freshwater (rainwater) in the street as opposed to salt water. The city is monitoring the performance of the recently installed valves during recent “king tides” and northeasterly wind events to verify they are working properly.Before Hurricane Irma, in an effort to inhibit tide water from backing up into the storm drainage system, the city installed four of these tide flow preventer valves into existing pipes. These valves allow stormwater to drain out under normal, low tide conditions.  View/Download a comprehensive presentation of this project here.

It is anticipated that the valve installation will be completed by the end of January 2018 at a cost of approximately $591,000 of which up to one-third will be reimbursed by the St. Johns River Water Management District.

For more information about these valves, contact the Public Works Department at 904.825.1040 for more information.