Plan Update Could Lower Flood Insurance Rates

SARASOTA, Fla. — Florida Atlantic University has completed its draft updates to the Sarasota County and city of Sarasota watershed master plans.

If they're approved by the Insurance Services Office and the governing bodies of the city and county, they could contribute to an increase in the discount that property owners receive in the National Flood Insurance Program.

Because of their Community Rating System Class 5 rating, property owners in the county and the cities of Sarasota, Venice and North Port qualify for a 25% NFIP discount. Residents of Longboat Key, which holds a Class 6 rating, can get a 20% discount.

The focus of the updates is flood prevention, said Fred Bloetsher, an FAU engineering professor, in a virtual presentation of the updates Thursday night via Zoom.

Watershed master planning is intended to get local governments working together, he said. No matter how hardened a jurisdiction is, if its neighbors aren't equally hardened, water will "just run around your hardening," he said.

And because it flows downhill, it's headed toward areas where there's already water that needs to be managed, he said.

FAU studied the HUC 12 basins in Sarasota and the unincorporated areas of the county, he said. A HUC — Hydrologic Unit Code — 12 is an area of up to 40,000 acres, according to the U.S. Geological Survey.

The county has about 30 of them, while there are four or five in the city of Sarasota.

Modeling where water will flow requires considering a number of existing factors, he said, including topography — the physical features of an area; the water table; surface water; soil conditions; and land uses.

Then, future land uses, sea level rise, "king" tides and extreme storm events have to be considered.

A king tide, as defined by the Environmental Protection Agency, is an extra-high tide at a coastal location. Such tides will be influenced by sea level rise, Bloetsher said.

The National Oceanographic and Atmospheric Administration sets a 5-foot sea level rise benchmark for planning, he said, but that's a distant risk.

"I'm here to tell you that's not happening anytime soon," he said — at least not for another 100-150 years.

More likely, coastal areas will see an inch of rise over the next 20-30 years, he said. They should be planning for that now, and revise their plans periodically based on reality.

"You don't necessarily want to build for something that might happen 150 years later," Bloetsher said.

But it's possible to build now in a way that will allow for enhancements later, such as by designing sea walls so they can be added on to, he said.

Though it was the most destructive element of hurricanes Helene and Milton last fall, storm surge wasn't considered in the planning models, he said.

It's very hard to predict and plan for and isn't required to be included, he said.

FAU's recommendations include a "period table" of ways to reduce flooding, Bloetsher said. It's laid out by options for "pluvial" — rain — water, such as pervious paving and rain harvesting; "fluvial" — surface — water, including injection wells and constructed wetlands; and tidal waters, with sea walls and levees.

Limiting development in the floodplain wasn't considered, he said. It's not a factor in CRS' rating system. he said, and in this part of Florida the water table is so high that an empty field can flood from a rainstorm.

Picking which options to pursue is a policy decision, Bloetsher said, and will depend on the funding that's available.

In the meantime, the county and city should continue to maintain their current systems and consider upgrading or adding to them, he said.

And everyone should bear in mind a lesson from his profession.

"One of the things you learn in engineering is that problems are never solved," he said. "You just run into new ones."

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