Protecting the Don CeSar neighborhood from flooding will take a lengthy, costly effort

The city and its consulting engineers are working on a plan to protect the Don CeSar neighborhood peninsula from tidal surge and stormwater flooding. But it won’t be cheap, as preliminary construction cost estimate range from $18.6 million to $25 million.

ST. PETE BEACH — It will take an ambitious, costly public-private partnership using state and federal funds over several years to protect the Don CeSar neighborhood peninsula from tidal surge and stormwater flooding.

During a Sept. 15 commission meeting, City Manager Alex Rey said the Don CeSar neighborhood, bounded by Gulf Boulevard, the Pinellas Bayway and McPherson Bayou, is the lowest lying area of the city and “most at risk from sea level rise and tidal flooding. … Efforts have started to come up with possible solutions. Work from the (city’s consultant HALFF) is fairly preliminary with a lot more details to be worked out.”

HALFF presented suggestions and conceptual design to city commissioners, with preliminary construction cost estimates ranging from $18.6 million to $25 million, not counting “soft costs” of potential waterfront property acquisition.

Since the Don CeSar neighborhood is surrounded on three sides by McPherson Bayou, consultants advised seawalls should be raised 2½ feet, with berms included to prevent tidal flooding from entering onto streets that open directly to the bayou. Currently, open street ends invite tidal flooding and allow frequent inundation of saltwater into the roadway, the report noted.

Project manager Phillip Keyes explained “the plan is to button up open street ends … replacing it with large drainage pipes and backflow preventers.”

In building up a barrier seawall, the trick will be to work with private property owners who will want to maintain access to their docks and boats.

Under the consultant’s plan, streets such as Maritana Drive and Debazan Avenue will be raised, and transformed into one-way, single-lane access streets, some including sidewalks, with stormwater infrastructure beneath the surface to direct rainwater. Rainwater would be directed into a large mitigation pond installed at the 3.9-acre Lazarillo Park. The park’s tennis courts and playground would be relocated on its greenspace.

Guillermo Simon, coastal engineer, explained a Lazarillo Park retention pond is the obvious location to collect stormwater and street flooding, so it could be pumped back out into the bayou. As currently envisioned, during a rain event, 8,000 gallons of rainwater per minute would be pumped from the retention pond and into the bayou; “as the water rises during a rain event it may reach the streets, which are generally lower than properties. Streets can also be used to store some of the water causing some street flooding, but most of it can exit the system,” the consultant told commissioners.

Kimberly Miller, resiliency planner, said the overall plan “first and foremost is to reduce nuisance and tidal flooding that is plaguing the neighborhood. Keeping saltwater out of the streets meets a number of objectives, so the neighborhood will still be a great place to live 30 years down the road.”

Constraints faced by the project are a rapidly increasing sea level, high water table, minimal drainage network, low-lying roads, existing boat docks, and street ends that open to the water and serve as a funnel for tides to come onto roadways, she said.

Rey said the consultant’s report offers a very generic concept plan to meet needs to 2050 and 2060. He added “intermediate solutions have already started improve quality of life.”

He added at some point the city will hold workshops and seek federal and state funding. “How do we pay for all of this? Twenty-five million sounds like a big number, but not for tomorrow, it’s a 30 or 40 years solution.”

The plan is to make things incrementally better, he added.

Commissioner Ward Friszolowski said the area is the “most challenging neighborhood in the whole city in terms of dealing with these issues.”

He noted a majority of the perimeter seawall is privately owned and will take a lot of cooperation.

Sea level rise is going to be getting worse and king tides are already an issue, he said.

“It’s a mini New Orleans, it’s in a bowl,” he added.