US Army Corps of Engineers
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Civil Works Public Notices

Emergency Dredging Green Bay Dredge Cut Environmental Assessment

U.S. Army Corp of Engineers, Rock Island District
Published May 22, 2020
Pool 19 Emergency Dredge Placement Site 24

Map of the Pool 19 Emergency Dredge Placement Site 24

The U.S. Army Corps of Engineers, Rock Island District has released for public review the report titled: Emergency Dredging Green Bay Dredge Cut Environmental Assessment (EA), dated May 2020. The public is invited to submit comments regarding the alternative analysis for this project through June 26. Comments can be submitted via this online COMMENT FORM, through email at: PublicInvolvement@usace.army.mil, or by writing to the address below.

The purpose of this emergency dredging project is to restore the navigation channel back to standard operating standards. Restoring the channel would allow commercial navigation to continue with a reliable and safe navigation channel depth and width. Work to restore the area would begin as soon as practicable after the 2020 spring flood season. 

To view a full copy of the report click here: Emergency Dredging Green Bay Dredge Cut Environmental Assessment

To request a paper copy or CD, contact the Environmental Compliance Branch at 309-794-5791, email: PublicInvolvement@usace.army.mil, or write to :

U.S. Army Corps of Engineers
Rock Island District, ATTN: Joseph Jordan
Clock Tower Building – P.O. Box 2004
Rock Island, IL 61204-2004

PROJECT INFORMATION

The Emergency Dredging Green Bay Dredge Cut (Project) is located in Pool 19 along the right descending bank of the Upper Mississippi River, between river miles 389.0 and 390.0. The navigation channel centerline is the border between Illinois and Iowa (Henderson & Hancock Counties and Lee County, respectively). During the 2019 navigation season, the District identified approximately 133,000 cubic yards of material obstructing the navigation channel in the Mississippi River 9 – foot navigation project. The District’s concern is when the river’s flood elevations return to normal river levels, the sediment will block commercial shipping at this location. This would cause navigation delays for barges travelling upstream and downstream. The District commander issued an emergency dredging declaration on August 17, 2019, to remove the sediment, thereby returning the navigation channel to standard operating conditions.

The Project area has not been dredged since 1955. Additionally, the current dredging requirement is not within any of the 1955 dredging footprint. This area is not a recurrent dredging area. Prolonged high water in 2019 shifted the river bottom significantly in previously stable river reaches. Due to the lack of dredging requirements, the District has not completed a Dredged Material Management Plan for this area. This EA assesses the potential impacts of dredging this new shoaling and placement of dredged material.

PROPOSED AND ALTERNATIVE ACTIONS

The purpose of this emergency dredging project is to restore the navigation channel back to standard operating standards. Restoring the channel would allow commercial navigation to continue with a reliable and safe navigation channel depth and width. Work to restore the area would begin as soon as practicable after the 2020 spring flood season. 

A total of 24 alternatives were considered during the planning process and are described in Section II of the Emergency Dredging Green Bay Dredge Cut Environmental Assessment. A group of preferred alternatives were screened using an alternative matrix to determine placement sites, which meet the Federal Standard for environmental acceptability and cost effectiveness.

Proposed Action

Site 24, an unused water retention pond from an adjacent previous industrial operation, is the District’s preferred alternative. This site has the capacity for the emergency dredged material quantity, is an upland site without natural resource impacts, and the local land owners support using this site. Site 24 is located in Lee, County, within the Green Bay Levee and Drainage District (GBLDD). The District would remove the material from the channel using hydraulic dredging. Placement of the hydraulically dredged material will require management of the return water, as the sand/water mixture settles the water would be directed through the GBLDD’s drainage ditches.