EA and FONSI for Caloosahatchee River – Alum Treatment Project Section 408

Published Dec. 6, 2023

The U.S. Army Corps of Engineers (USACE) Jacksonville District announces the availability of the final Environmental Assessment (EA) and Finding of No Significant Impact (FONSI) for Caloosahatchee River (C-43) West Basin Storage Reservoir – Reservoir Alum Treatment Project.

USACE conducted an EA, in response to a request from the South Florida Water Management District (SFWMD), to modify Caloosahatchee (C-43) West Basin Storage Reservoir (C-43 WBSR) by constructing an Alum Injection System on the C-43 WBSR Pump Station 470 pursuant to 33 U.S.C. 408 (Section 408). The EA evaluated various alternatives proposed by the SFWMD that would improve water quality in the Caloosahatchee River and downstream estuary in the study area. A description of the preferred alternative is described below:

The in-reservoir alum treatment system will be installed at the inflow of the C-43 WBSR. On the north side of Pump Station S-470, a tank farm will be constructed to store enough alum for a two-week period of average usage. The alum will be dispensed into the C-43 WBSR intake channels via four alum feed pumps from the five 13,800-gallon bulk alum storage tanks. Rapid, high-energy mixing of the alum will occur within the suction intake through the S-470 pumps, and in the discharge piping of Pump Station S-470 into the C-43 WBS

The C-43 WBSR project is designed to capture and store water from Lake Okeechobee and the C-43 Basin during Florida’s rainy season, retaining excess water during the wet season to minimize high flows which cause freshwater flushing in the estuary. The C-43 WBSR is currently under construction on a 10,700-acre (ac) parcel owned by South Florida Water Management District (SFWMD) and, when fully constructed, it will store approximately 55.4 billion gallons of water (170,000 ac-feet), for the congressionally authorized Comprehensive Everglades Restoration Plan (CERP) project. The C-43 WBSR, expected to be completed in 2024, will include construction of two 5,000-ac reservoir storage cells (Cells 1 and 2), three pump stations, a perimeter canal along with associated water control structures, and improvements to the State Road 80 Bridge and the Townsend Canal, which ultimately connects to the Caloosahatchee River.

The EA has been prepared and has been coordinated for Federal, Tribal, state, and public review. All comments submitted during the public review period have been responded to in the Final EA.

The EA and FONSI are available at the following link. Scroll to Hendry County, and documents are located on the bottom row:


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Jaz Levario

Release no. 23-080