Major construction has been completed on the C-23 and C-24 Stormwater Treatment Areas, marking another milestone in the long-running effort to restore the St. Lucie Estuary and southern Indian River Lagoon.
State and local officials gathered last week to celebrate the progress on the projects, which are part of the larger Indian River Lagoon-South restoration initiative. The restoration plan, authorized in 2007, is designed to improve water quality, restore habitat and more closely mimic the region's natural freshwater flows.
Michael Drog, a project manager with the U.S. Army Corps of Engineers, said the treatment areas represent one piece of a broader restoration effort that has been underway for years.
"The C-23 and C-24 project components are part of the Indian River Lagoon-South project, which was authorized in 2007 and serves many ecosystem restoration goals for the affected basins and estuaries, including reestablishing the natural pattern of freshwater flows, native wetlands, and improving diverse plant and animal species for the Southern Indian River Lagoon and the St. Lucie Estuary," he said.
The project has steadily advanced over the past several years, with construction on the treatment areas beginning in 2021.
"We recently celebrated some big successes out of the project. We started the C-23, C-24 stormwater treatment area in 2021, and we recognized completion of the major construction features of that component here just recently last week," Drog said.
The U.S. Army Corps of Engineers has also secured funding for an interim pump station that will allow portions of the project to begin operating before all remaining components are complete.
"In addition, we also were able to move forward with adding an interim pump station to allow operations of the C-23, C-24 stormwater treatment area prior to the rest of the project components coming online," he said.
Although major construction has wrapped up, work will continue as crews establish vegetation throughout the treatment areas while additional infrastructure is built.
"At this time, what we'll be doing is utilizing the project as a rainfall-driven system. In the meantime, we'll be constructing a pump station, which will allow the permanent project benefits to occur, which includes 240 CFS of inflows from the C-24 canal and then 200 cubic feet per second outflows into Canal 71 and eventually into Ten Mile Creek and through the North Fork to the St. Lucie River," he said.
The treatment areas must also mature before they can deliver their full water-quality benefits.
"Right now, what we're working on for grow-in is we're establishing the natural vegetation, which will contribute to water quality by removing phosphorus and nitrogen from water in the basin. Meanwhile, we're also monitoring the health of the embankments, the health of the grow-in vegetation, and also working to establish that interim pump station to allow the project to achieve benefits," Drog said.
Drog said engineers are also making progress on the North Reservoir, which will operate alongside the South Reservoir as part of the larger restoration project.
When completed, the Indian River Lagoon-South project will provide more than 130,000 acre-feet of additional water storage, about 9,000 acres of stormwater treatment areas and nearly 90,000 acres of restored natural areas. The project is currently scheduled for completion in 2031.