The Indian River Lagoon is the most biodiverse estuarine system in all of North America. The Final Feasibility Study for the Indian River Lagoon-South project recommends a plan in Martin, St. Lucie, and Okeechobee Counties that will improve water quality within the St. Lucie Estuary (SLE) and the Indian River Lagoon (IRL) by: reducing the damaging effects of watershed runoff, reducing high peak freshwater discharges to control salinity levels, and reducing nutrient loads, pesticides and other pollutants. The project will also provide water supply for agriculture to offset reliance on the Floridian Aquifer.

The plan includes 170,000 acre feet of storage in reservoirs (C-44, C-23 and 24 North and South Reservoirs and C-25 Reservoir) and storm water treatment areas (C-44, C-23, C-24 and C-25), provides storage on 92,000 acres of natural storage areas (Allapattah, Palmar, and Cypress Creek), and removes 7,900,000 cubic yards of muck from the St. Lucie River and Estuary.

C-44 Reservoir, the C-44 East STA, the C-44 West STA

The C-44 Reservoir and STAs replace the original C-44 Reservoir, C-44 West STA, C-44 East STA, and C-23/44 STA from the Indian River Lagoon South Feasibility Study. All component features associated with those components, including real estate, are no longer applicable. The features of the new C-44 components are explained below. Some structure numbers used for the C-44 component features in the feasibility study are used for similar features in the new components, however they are not the same structures.

The new C-44 reservoir and STAs include a 3,315-acre, 10-foot deep aboveground reservoir, a 3,000-acre STA to the west, and a 3,000-acre STA to the east. The C-44 reservoir and STAs are located in Martin County adjacent to and north of C-44 canal, and approximately midway between Lake Okeechobee and the Florida Turnpike.

C-23/24 Basins
The recommended plan includes five components within the C-23/24 Basin. These components are the C-23/24 North Reservoir, C-23/24 South Reservoir, C-23/24 Stormwater Treatment Area, Cypress Creek Complex - Natural Storage and Water Quality Treatment Area, and Allapattah Complex - Natural Storage and Water Quality Treatment Area.

An operational feature of the IRL-S Plan known as the northern and southern diversions are accomplished via use of the construction features described for this basin. The Allapattah - Natural Storage and Water Quality Treatment Area are located in Martin County. The balance of the C-23/24 Basin features are located in St. Lucie and Okeechobee Counties.

C-25 and Northfork and Southfork Basins
The recommended plan includes three components within the C-25 Basin and North Fork and South Fork basins of the SLR. These components include the C-25 Reservoir and Stormwater Treatment Area, Muck Remediation, Artificial Habitat, and North Fork Floodplain Restoration.