Public Comment for Proposed 8.5 Square Mile Area Cutoff Wall pursuant to Section 408

USACE announces public comment on proposed seepage cutoff wall in the 8.5 Square Mile Area

Location of Proposed Seepage Cutoff Wall in 8.5 Square Mile Area

The U.S. Army Corps of Engineers Jacksonville District announces a 30-day public comment period for the Draft Environmental Assessment (EA) and Proposed Finding of No Significant Impact (FONSI) for the South Florida Water Management District’s (SFWMD) proposed construction of a seepage cutoff wall in the L-357W levee. The Jacksonville District, in response to a request from the SFWMD, is evaluating a modification to an existing Central and Southern Florida (C&SF) Project pursuant to 33 U.S.C. 408 (Section 408) to improve seepage management in the 8.5 Square Mile Area (SMA), also known as the Las Palmas community. The proposed action would be in Miami-Dade County. Improved seepage management would allow for greater operational flexibility of the Central and Southern Florida Project. Comments are due April 9, 2021.

Review the Draft Environmental Assessment (EA) and Proposed FONSI for the Proposed 8.5 Square Mile Area Seepage Cutoff Wall below:

Notice of Availability

Draft EA and FONSI

Appendix A

Appendix B

Appendix C

The SFWMD proposed action would include the construction of a 2.3-mile seepage cutoff wall made of a mix of soil, cement and bentonite slurry along the L-357W levee northwest of the S-357 pump station, and along the south side of the C-358 canal. The approximate depth of the curtain wall would be 55 to 65 feet deep below ground, with an approximate thickness of 28 inches. Construction is subject to Corps approval pursuant to 33 U.S.C. 408. If approval is granted, the SFWMD will complete construction at no cost to the Corps.

Operations in the project area are currently governed by the 2020 Combined Operational Plan (COP) Water Control Plan. Providing flood mitigation in the 8.5 SMA can influence regional operations including releases from Water Conservation Area (WCA) 3A to Everglades National Park (ENP). Conditions in October and November of 2020, including Tropical Storm Eta, highlight the role 8.5 SMA flood mitigation has in limiting operation of the WCAs during high water events. Various seepage management alternatives have been evaluated to afford increased system-wide flexibility under the 2020 COP Water Control Plan and future water control plans.

Please submit comments on the Draft Environmental Assessment (EA) and Proposed FONSI via email to Melissa.A.Nasuti@usace.army.mil (recommended subject: “8.5 SMA EA Comments”) by April 9, 2021.

What is Section 408?

Section 408 is the process that allows alteration to a federally authorized project. The proposed project cannot pose a risk to the public interest and will not impair the usefulness of the federally authorized project. Examples of federally authorized projects include, but are not limited to levees, dams and the federal navigation channel.

This requirement was established in Section 14 of the Rivers and Harbors Act of 1899, codified at 33 United States Code (USC) 408 (Section 408).

Section 408

Through the Civil Works program, the US Army Corps of Engineers (USACE) serves the public by providing the Nation with quality and responsive management of the Nation’s water resources.  As a result, USACE, in partnership with stakeholders, has constructed many Civil Works projects across the Nation’s landscape.  Given the widespread locations of these projects, many embedded within communities, over time there may be a need for others outside of USACE to alter or occupy these projects and their associated lands.  Reasons for alterations could include improvements to the projects; relocation of part of the project; or installing utilities or other non-project features.

In order to ensure that these projects continue to provide their intended benefits to the public, Congress mandated that any use or alteration of a Civil Works project by another party is subject to the approval of USACE.  This requirement was established in Section 14 of the Rivers and Harbors Act of 1899, which has since been amended several times and is codified at 33 USC 408 (Section 408).

Section 408 provides that USACE may grant permission for another party to alter a Civil Works project upon a determination that the alteration proposed will not be injurious to the public interest and will not impair the usefulness of the Civil Works project.

Additional Information on Section 408

USACE’s procedures for reviewing requests for Section 408 permission is contained in Engineer Circular (EC) 1165-2-220.  The corresponding internal guidance related to designating a lead district as referenced in EC 1165-2-220 can be found at this link.

To view a fact sheet with additional information about Section 408 and the revised policy, click here.

USACE reviewed and considered public comment on the draft EC 1165-2-220 to inform the final policy and procedural guidance.  To view the summary of comments received, click here.