Army Corps awards $136 million contract for marsh to curb St. Lucie River pollution
Max Chesnes
ST. LUCIE COUNTY — The plan to build a marsh and two reservoirs to filter polluted water flowing into the St. Lucie River just reached a major milestone.
A $136.6 million contract to build part of the Indian River Lagoon South C-23/C-24 Reservoir and Stormwater Treatment Area was finalized this week, the Army Corps of Engineers announced Wednesday. Kiewit Infrastructure South Co. in Sunrise will build the stormwater treatment area. The reservoir contracts have not yet been awarded.
The human-made marsh north of State Road 70 will reduce pollution, including sediment, nitrogen and phosphorus flowing into the St. Lucie River Estuary and the southern section of the Indian River Lagoon.
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Once completed, the marsh could store an estimated 1.5 billion gallons of water — enough to douse nearly 5,000 acres of land in a foot of water, according to Michael Drog, the Corps' project manager.
The water entering the marsh will be stored in two reservoirs that could hold over 4 billion gallons of rainfall runoff annually, once both are completed in roughly a decade.
That water currently drains from an 827-square-mile watershed in western St. Lucie County into the North Fork of the St. Lucie River, polluting it with algae-feeding nutrients, bacteria, herbicides, pesticides and more.
"It's huge news, we're really excited about it," said John Maehl, Martin County's ecosystem restoration manager. "This is a pretty significant (marsh) in scope, and it will provide huge nutrient pollution reductions."
The marsh and reservoirs combined could remove 7.9 million cubic yards of muck from the river and reduce phosphorus by 41% and nitrogen by 26%. That's about 100 times more than the volume of the iconic “Spaceship Earth” ball at Epcot in Orlando.
That will help reduce cyanobacteria blooms, commonly called blue-green algae and sometimes containing the toxin microcystin.
The marsh also can serve as habitat for migratory birds, Maehl said.
Florida reservoir, STA projects
Construction on the marsh is expected to be completed by 2025, according to the Corps. The northern reservoir will finish next, estimated to be completed by 2028. Finally, the southern reservoir will wrap sometime in 2031.
The estimated $2.1 billion water project was approved in 2000 and funded in 2007.
The project, being built in partnership by the Corps and South Florida Water Management District (SFWMD), is part of the Comprehensive Everglades Restoration Plan (CERP), which former President Bill Clinton signed into law in 2000 and Congress funded in the 2007 Water Resources Development Act.
More potential storage capacity will be added to the system in a few years, when the SFWMD breaks ground on the C-25 Reservoir project.
According to the Corps, the two reservoirs and treatment marsh could provide:
- 12,000 acres of aboveground storage
- 9,000 acres of manmade wetlands
- 90,000 acres of natural areas
- 53,000 acres of restored wetlands (providing additional water storage)
- 90 acres of artificial submerged habitat created for aquatic vegetation
- 922 acres of submerged aquatic vegetation restored
- 2,650 acres of benthic habitat created in St. Lucie River and estuary
- 889 acres of restored oyster habitat
- $6.1 million in improved agricultural productivity through improved freshwater supplies
- $6 billion in regional economic benefit (based on 2007 price levels).
State water managers also recently completed a 6,600-acre water farm at Evans Properties' Bluefield Grove, estimated to store 9.2 billion gallons of rainfall runoff annually from western St. Lucie County.
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Max Chesnes is a TCPalm environment reporter focusing on issues facing the Indian River Lagoon, St. Lucie River and Lake Okeechobee. You can keep up with Max on Twitter @MaxChesnes, email him at max.chesnes@tcpalm.com and give him a call at 772-978-2224.