St. Pete is ‘banking’ on seagrass efforts

Tampa Bay is losing its seagrass, and St. Petersburg officials plan to construct a mitigation bank on city-owned submerged land adjacent to the Vinoy Park beach.

However, the engineering department needs tons of natural material to fill a 32-acre dredge hole and support the critical habitat’s growth. Meanwhile, just across the Skyway Bridge, the Manatee County Port Authority is extending a docking facility 600 feet and deepening the adjacent channels.

The two parties realized the dredging project would generate enough material to satisfy St. Pete’s need “in one event,” reducing its impacts. At the May 18 meeting, city council members unanimously approved an Interlocal Agreement that provides an extensive mutual benefit.

“They (Port Manatee) need to dispose of that material somewhere,” said Brejesh Prayman, director of engineering. “Ironically, because our numbers are almost exactly the same, we have the opportunity to receive that material.

“It’s serendipity that the numbers were that close.”

Prayman relayed that the formal partnership also increases the odds of the Army Corps of Engineers quickly approving necessary permits. Port officials should begin shipping the material to downtown St. Pete’s waterfront by the end of summer.

City officials dug the “decades-old” dredge hole adjacent to waterfront parks to support local developments. They now need 470,000 cubic yards of essentially the same material it removed to fill the trench.

Tampa Bay has lost 12% of its seagrass, which is critical to marine life and water quality. Photo: Tampa Bay Estuary Program.

Seagrass loss

The agreement states that the city is an active Tampa Bay Estuary Program member and has worked to restore and enhance local seagrass since 1995. The habitat is vital to an abundance of marine life and water quality.

In February, the Southwest Florida Water Management District released its local mapping results that showed the bay endured seagrass losses for three consecutive study periods for the first time since biennial tracking began in 1988.

Coverage in Old Tampa Bay is at an all-time low, and Florida’s largest open-water estuary lost 12%, or 4,161 acres, of its seagrass between 2020 and 2022. Maya Burke, assistant director of the TBEP, said in February that researchers are particularly interested in losses along the southeastern shore of Middle Tampa Bay – from Apollo Beach towards Port Manatee.

In April 2021, state officials released millions of gallons of contaminated wastewater into the bay from the Piney Point fertilizer plant in Manatee County to prevent a reservoir leak from flooding surrounding neighborhoods. City officials did not mention Port Manatee’s previous or additional seagrass loss in the meeting.

Mitigation credits

However, the agreement states that the agency will receive six of the city’s seagrass mitigation credits “to offset unavoidable impacts generated by the removal of material.”

According to a December 2021 University of Florida Coastal Policy Lab report, marine “mitigation is a highly regulated market-based management system that has been practiced in Florida since at least the mid-1990s.” It states that “mitigation banking for marine resources is a relatively novel application … typically limited to ports and local governments mitigating impacts of their own activities over time.”

The report uses the Port of Los Angeles, the City of St. Peterburg and Sarasota County as examples. The interlocal agreement notes that city officials began designing restoration plans for the mitigation bank in 2015.

The credits – three to start and three at the project’s conclusion – will allow Port Manatee to solicit construction bids. In exchange, the agency will transport the dredged material about 12 miles via barge to St. Pete.

Prayman explained that Port contractors would mechanically place the fill in the “extensively deep” hole using interior containment cells to reduce turbidity. Once filled, the agreement states that “the city expects to generate marketable seagrass mitigation credits and operate the bank.”

During the meeting, Councilmember Lisset Hanewicz noted the seagrass loss in the bay and said the 32-acre bank would provide some relief. “It’s a perfect example of how governments can work together and find a mutually beneficial project,” she added.

A graphic showing the project’s scope. Screengrab.

Project details

In addition to preventing seagrass growth due to its depth, Prayman relayed that the dredging hole also causes beach erosion along the parks. City officials will complete necessary surveying and monitoring to ensure the project doesn’t negatively impact the surrounding area or marine life.

“You do have to do quite a bit of monitoring on that,” Prayman said. “We did extensive monitoring today – we even had people on kayaks looking out for manatees.”

He added that the city would provide precise GPS coordinates, and Port workers would ensure the containment cells do not trap wildlife. Once filled, Prayman said they would give the soil time to settle before planting new seagrass.

He expects the process to take eight or nine months, and Attorney Michael Dema believes the Army Corps of Engineers will issue final permitting in June. Councilmember Ed Montanari noted the city should prohibit boat traffic through the area.

Dema relayed that the Florida Fish and Wildlife Conservation Commission (FWC) must provide its regulatory consent, and he will soon bring an amended ordinance to the council for approval. He is also working with Mike Jefferis, leisure services administrator, to implement a “pardon our dust” campaign around the parks that also highlights new boating restrictions.

While Dema noted the ordinance would prohibit combustible gas engines, Councilmember Copley Gerdes noted increasingly popular electric motors could also “tear up” shallow seagrass.

“Ultimately, we’re going to be bound by a permit that requires us to protect that seagrass above and beyond anything else,” Dema said. “So, duly noted.”

The council unanimously approved the interlocal agreement to receive Port Manatee’s fill material in exchange for mitigation credits to offset its “unavoidable seagrass impacts.”