The Army Corps C23-C24 reservoirs and stormwater treatment area (STA) represent a major step in efforts to clean the Indian River Lagoon and St. Lucie River, addressing decades of water quality challenges in the region.

Army Corps C23-C24 Reservoirs and STA: Project Overview

The U.S. Army Corps of Engineers is constructing two large reservoirs and a stormwater treatment area west of Fort Pierce as part of the Indian River Lagoon-South (IRL-South) Restoration Project. This initiative is a component of the broader Comprehensive Everglades Restoration Plan (CERP), which aims to restore water quality and natural flow patterns across South Florida.

According to the Army Corps, the C23-C24 reservoirs will store a combined 29.4 billion gallons of water, while the adjacent STA will provide storage for 997 million gallons. These facilities are designed to filter out millions of pounds of sediment, nitrogen, and phosphorus before water reaches the lagoon and river. Local residents have also become increasingly involved in environmental advocacy, such as campaigns to protect manatees in the C-24 Canal, highlighting the community’s commitment to safeguarding aquatic life.

Key Details and Construction Timeline

Construction crews are active along Sneed Road, roughly seven miles west of Florida’s Turnpike. Heavy machinery is moving earth and installing infrastructure, with temporary rural road closures occurring for culvert and utility work.

According to Michael Bush, project manager for the Army Corps of Engineers, the $2.1 billion C23-C24 project will remove significant amounts of pollutants each year, helping to improve the health of the estuary and lagoon.

C23-C24 Project Components

• Stormwater Treatment Area (STA): 997 million gallons of storage, lined with cattails and other vegetation to filter sediment and pollutants. Completion expected by spring 2026.
• South Reservoir: 3,537 acres, 16.5 feet deep, 18.83 billion gallons of storage. Projected completion by end of 2030.
• North Reservoir: 2,000 acres, 16.5 feet deep, 10.64 billion gallons of storage. Projected completion by end of 2031.

Purpose and Environmental Impact

The C23-C24 reservoirs are designed to capture stormwater runoff from an 827-square-mile watershed in western St. Lucie County. This runoff currently flows into the North Fork of the St. Lucie River and eventually the southern Indian River Lagoon.

Stormwater in this area contains herbicides, pesticides, fecal bacteria, sediment, and nutrients such as nitrogen and phosphorus. According to the Army Corps, these pollutants contribute to toxic algae blooms, degrade water quality, and threaten aquatic life, including oysters and seagrass. In response to these threats, some Port St. Lucie residents have advocated for boating restrictions to better safeguard manatees and reduce further ecological harm in the C-24 Canal.

Pollution Reduction Goals

• Provide 42 billion gallons of new water storage across IRL-South projects
• Reduce nitrogen and phosphorus loads by 597 metric tons per year
• Moderate flows to the estuary and improve salinity levels
• Rehydrate the North Fork floodplain
• Create new wetland, upland, and open-water habitats

Other IRL-South Restoration Projects

The Indian River Lagoon-South Restoration Project includes several major components, each targeting specific watersheds and pollution sources:

• C44 Reservoir and STA: Near Indiantown, completed and operational. Holds up to 16.5 billion gallons, capturing stormwater from western Martin County before releasing it to the C44 Canal and St. Lucie River.
• C25 Reservoir and STA: North of Taylor Creek and south of Florida’s Turnpike. Designed to hold 1.7 billion gallons annually, it treats stormwater from northwest St. Lucie County before releasing it into Taylor Creek and the lagoon near Fort Pierce North Bridge.

According to the Army Corps, these projects are part of a $5.5 billion regional effort, itself a component of the $23 billion CERP initiative.

Muck Removal and Algal Bloom Control

Future plans include removing approximately 7.9 million cubic yards of muck from the north and south forks of the St. Lucie River and the middle estuary. This muck contains legacy nutrients that fuel cyanobacteria (blue-green algae) blooms, which can produce toxins such as microcystin. In addition to water quality projects, local pushes for boating restrictions in the C-24 Canal have emerged as another strategy to protect sensitive species and habitats.

According to John Maehl, Martin County Public Works environmental resource administrator, removing muck will create 1,300 acres of new habitat for oysters and other aquatic life. The restored marshes may also serve as habitat for migratory birds.

Challenges and Ongoing Concerns

While the IRL-South projects offer substantial benefits, experts note that they are expensive, require years to build, and must be operated effectively to achieve their goals. Mark Perry, executive director of the Florida Oceanographic Society, emphasized the importance of addressing pollution at its source, such as through improved basin management and stricter pollution reduction programs.

A 2020 investigation by TCPalm reported that existing Basin Action Management Plans have not fully succeeded in stopping runoff pollution, highlighting the need for continued focus on source control.

Indian River Lagoon: Ecological and Economic Importance

The Indian River Lagoon is recognized as one of North America’s most biodiverse estuaries, home to over 4,300 species of plants and animals. The Environmental Protection Agency (EPA) has designated it an Estuary of National Significance.

According to the Army Corps, the lagoon contributes over $730 million to the regional economy. However, altered water flows, outdated stormwater systems, and fertilizer-laden runoff have degraded water quality and habitat over time.

Water Flow and Restoration Efforts

Historically, excess water from Lake Okeechobee was diverted east to the St. Lucie River and west to the Caloosahatchee River, reducing natural flows to the Everglades. These freshwater releases have lowered salinity and increased pollutant loads in the estuary.

The Army Corps reports that the IRL-South project will help reverse some of these damaging effects, improving conditions for both wildlife and people.

Frequently Asked Questions About Army Corps C23-C24 Reservoirs

What is the purpose of the Army Corps C23-C24 reservoirs?

The C23-C24 reservoirs are designed to capture and store stormwater runoff before it reaches the Indian River Lagoon and St. Lucie River. This helps remove pollutants and improve water quality in the region.

How much water will the C23-C24 reservoirs and STA hold?

According to the Army Corps, the two reservoirs will store 29.4 billion gallons of water, and the stormwater treatment area will hold 997 million gallons.

Are there other projects like the C23-C24 reservoirs in the Indian River Lagoon area?

Yes, the IRL-South Restoration Project includes other major efforts, such as the C44 and C25 reservoirs and stormwater treatment areas, targeting different watersheds in the region.

Can you visit the Army Corps C23-C24 reservoirs or STA?

The reservoirs and STA are primarily designed for water management and environmental restoration. Some areas may offer recreational opportunities in the future, but public access is currently limited during construction.

Where are the Army Corps C23-C24 reservoirs located?

The C23-C24 reservoirs and STA are located west of Fort Pierce in St. Lucie County, Florida, about seven miles west of Florida’s Turnpike along Sneed Road.

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