Pinecrest will need close to $40 million to upgrade its drainage system

Stormwater infrastructure in Pinecrest has long consisted of scattered French drains, drainage wells, and outflows to canals.

Last May, the village decided to finally tackle flooding and hired consultants from A.D.A. Engineering to survey existing infrastructure and develop a comprehensive plan for new projects. At the time, Vice Mayor Bob Ross mused that the village would be spending, “a third of a million dollars to find out that we need to spend millions more.”

He was right.

At an information meeting held for residents on Tuesday night, consultants revealed the estimated cost to address flooding in the 15 village sub-basins that need it most. The figure: $38.7 million.

That would pay for 15 different stand-alone projects, each integrating a mix of ex-filtration trenches, pump stations, catch basins, berms, and outfalls into canals with back-flow preventers. According to Alex Vazquez, A.D.A. Engineering vice president, the aim is discharge as much as is allowed into canals, and then get as much as possible of the remaining water underground into well fields.

A.D.A. ranked the projects according to a formula weighing — in the event of a 100-year storm — the severity of flooding, number of structures and roads inundated, canal overflow, and recorded complaints. Of the top 15, most projects are concentrated along canals on the village’s western side, although one is slated for the village’s northeastern corner, and two are suggested in the southeast.

The projects drew criticism from Mayor Cindy Lerner, who also chairs the National League of Cities’ environment committee.

She called the plan “too conservative” for not using mid-level or worst-case scenario projections for sea-level rise.

“I think we’re doing ourselves a disservice by being this conservative,” she said.

Though not directly on the coast, Pinecrest is still threatened by rising seas. Because of salt and fresh water’s different densities, canals can’t dump water into Biscayne Bay without canal elevations being higher than the bay. The higher the bay, the more water stays trapped in canals.

Vazquez defended the choice.

“It was decided by village staff and A.D.A. Engineering collectively that accounting for a mid-range sea-level rise for year 2030 would be prudent,” Vazquez said after the meeting, noting that the difference between mid-range and worst-case scenarios, “resulted in less than three inches of additional flooding … concentrated along the canals and isolated areas with low elevations.”

He added that sea-level rise needed to be monitored, with new data used to update stormwater master plans every five years. Drainage infrastructure, he said, is typically re-hauled every 15 to 20 years.

A small group of assembled residents on Tuesday night grumbled about the plan, with many arguing that it should prioritize home flooding above all else.

Next steps for the village will be for the council to figure out where to get the money. With Pinecrest’s total annual operating budget equal to roughly half of the $38.7 million needed for all 15 projects, the village’s only options will be floating a massive bond or getting state and federal grants.

But with such a large sum needed, and grants now often requiring significant matching commitments from recipients, some council members warned residents that many projects might have to wait — and to expect a fight.

“It’s going to come up at council, and it’s going to get political,” Ross told the crowd.