The U.S. Army Corps of Engineers, Rock Island District, has released for public review, the Dubuque Forced Sewer Main Continuing Authorities Program Section 14 Feasibility Report and Integrated Environmental Assessment. The public is invited to submit comments regarding the alternative analysis and preferred alternative for this project through December 1.
The report and its appendices can be viewed at the following links:
The purpose of this Feasibility Report with Integrated Environmental Assessment is to evaluate the proposed project within the Continuing Authority Program and ensure U. S. Army Corps of Engineers planning guidance and National Environmental Policy Act requirements are met. The purpose of the Study is to formulate a plan using the USACE 6 Step Planning Process to stabilize the right descending riverbank of the Mississippi River on the southern edge of the City of Dubuque in Dubuque County, Iowa and to evaluate the potential effects of such action. This report provides planning, engineering, and preliminary construction details of the Tentatively Selected Plan. Final design and construction to proceed after the approval of the plan and receipt of appropriated funds for design and construction phases.
Comments can be submitted via this online COMMENT FORM , through email to: PublicInvolvement@usace.army.mil, or by writing to the address below.
Department of the Army
US Army Corps of Engineers, Rock Island District
Attn: Thorson (PD-F)
Clock Tower Building
P. O. Box 2004
Rock Island IL 61204-2004
The Study area is comprised of approximately 3,000 linear feet of riverbank south of the City of Dubuque, Iowa. The Dubuque Forced Sewer Main Section 14 Study is experiencing extended periods of high water and natural processes on the Mississippi River that have caused the right descending bank to erode. Natural processes along the riverbank have eroded the entire area with some areas of severe scour. This erosion has exposed the Dubuque Forced Sewer Main which transports 80% of the City of Dubuque’s wastewater. Years with extended periods of high water allowed these conditions to become worse. While these processes will continue to occur, this Study provides the opportunity to restore protection to vital infrastructure. Alternatives to this problem were evaluated and analyzed in this report to find the best solution.
PROPOSED ALTERNATIVE ACTIONS
During the process, four alternatives were considered. A Tentatively Selected Plan was developed after extensive data collection and public and agency collaboration. The planning team worked on varying options that will meet the purpose and need while addressing both agency and public suggestions and developed the following four alternatives that focused on varying percentages of land classification:
- No Action Alternative was based on the 1989 LUAP land classifications and proposes no change to those classifications.
- Alternative 1, Riprap Revetment - Tentatively Selected Plan, focused on balancing current conditions of conservation and recreation on Project lands.
- Alternative 2, Sheet Piles, Sheet piles are metal sheets pressed or molded to interlock with other such sheets. They are driven into the earth as piles and can be used to retain water, soil, or other materials.
- Alternative 3, Articulated Concrete Block Matting, is a system of interconnected concrete block units installed to provide an erosion resistant revetment. It is static protection and is applicable in high-risk applications where no additional bank or grade movement is allowable.
TENATIVELY SELECTED PLAN
All alternatives were evaluated against the Planning and Guidance criteria. The alternatives not selected consisted of driving sheet piling and using articulated concrete block matting. These alternatives lacked constructability and cost more than the tentatively selected alternative.
Alternative 1, the Tentatively Selected Plan, is the least cost alternative that fulfills project objectives while it 1) meets Project purposes and agency/public needs and desires, 2) is consistent with minimizing adverse environmental impacts and ensuring environmental sustainability, and 3) is compatible with all applicable laws and regulations as well as regional plans.