Treasure Coast Sun

St. Lucie County issued the following announcement on Sept. 29.

The U.S. Army Corps of Engineers (USACE), Jacksonville District announced the funding of two projects in St. Lucie County totaling more than $147 million for beach erosion and water quality improvements in the Indian River Lagoon.

USACE awarded a $136,637,750 construction contract for the Indian River Lagoon-South (IRL-S), C-23/C-24 Stormwater Treatment (STA) part of the Comprehensive Everglades Restoration Plan (CERP) to Kiewit Infrastructure South Co., of Sunrise, Florida. Additionally, the federal agency announced an $11.3 million contract to Great Lakes Dredge & Dock Co., LLC, of Houston, Texas, to construct a coastal storm risk management beach on South Hutchinson Island in St. Lucie County.

“The C-23/C-24 STA is the first major construction feature of the IRL-S project to address the C-23 and C-24 basins in St. Lucie County,” said Michael Drog, project manager with the Army Corps of Engineers. “When completed, this STA will provide an estimated 4,800 acre-foot of new storage and act to treat water from the future C-23/C-24 North and South Reservoirs.”

St. Lucie County Commissioner and Chair of the Erosion District Frannie Hutchinson has been working with the Army Corp to secure funding for this project for several years.

“This is fantastic news. A project of this magnitude will provide tremendous benefits for our water quality for generations to come,” added Commissioner Hutchinson. “This is perhaps our best week ever.”

Funding for the South Hutchinson Island beach project will be paid for with 35 percent of the funding from the Army Corp. and 65 percent from the Corps’ non-federal sponsor, the St. Lucie County Erosion District. The beach renourishment contract calls for the initial construction of a beach berm and vegetated dune along approximately 3.3 miles of the St. Lucie County shoreline, running south from Florida Department of Environmental Protection Range Monument R-98 to the Martin County line. Up to 800,000 cubic yards of sand will be dredged from federal waters off the St. Lucie County shore and placed on South Hutchinson Island to rebuild dunes and beaches. Dune vegetation will be planted once beach and berm construction are complete.

The Corps’ objectives are to reduce storm damage to property and infrastructure, including State Route A1A (a major hurricane evacuation route) within the project area, and to maintain environmental quality along the coast and adjacent areas for resident and visitor use, sea turtle habitat and aesthetics. Objectives over the course of the project’s 50-year analysis period also include maintaining recreational use of beach and nearshore areas for activities such as beach-going, surfing, fishing and wildlife viewing. The contractor is expected to begin mobilizing crew and equipment as early as November of this year. Construction is planned to be completed before May 1, 2022.

“This federal project has been nearly two decades in the making,” said Trisston Brown, Chief of the Jacksonville District’s Coastal/Navigation Section. “I am excited that success to launch this project has finally been achieved and initial construction of the St. Lucie South Hutchinson Island Coastal Storm Risk Management project is getting under way.”

Home to more than 3,000 species of plants and animals, the Indian River Lagoon is considered the most biologically diverse estuarine system in the continental United States.

The purpose of the STA is to reduce sediment, phosphorus and nitrogen going to the St. Lucie River Estuary and the southern portion of the Indian River Lagoon. Redirection of water from the C-23/24 basin to the north fork of the St. Lucie River will attenuate freshwater flows to the estuary.

Ultimately, the stored water will be released into the C-23/24 STA to sequester nutrients from water conveyed from the North and South Reservoirs. The C-23/24 STA is designed to remove phosphorus from stormwater entering the C-23/24 Reservoirs.

The multi-cell STA will be located both east and west of County Road (CR) 613 and consist of 1,970 acres of effective treatment area spread among five cells within the approximately 10-mile perimeter (two cells of roughly 200 acres each and three cells at roughly 500 acres each) and will have a normal operating depth of about 1 to 2- feet, 260 cubic feet per second (cfs) inflow and 200 cfs outflow. Inflowing water will be treated by filtering through emergent wetland vegetation.

Original source can be found here.