US Army Corps of Engineers
St. Paul District

Projects

Dredged Material Management Plan (DMMP): Pool 6

Published March 15, 2018
Updated: Sept. 19, 2019
Location

The Pool 6 Dredged Material Management Plan (DMMP) study area is located between Lock and Dam 5A at river mile 728.5 and Lock and Dam 6 at river mile 714.1. The study area borders the city of Winona, Minnesota, at the upstream end and extends downstream of the village of Trempealeau, Wisconsin.

Description

The U.S. Army Corps of Engineers operates and maintains the Upper Mississippi River 9-Foot Channel Navigation Project. The purpose of the DMMP is to prepare a coordinated long-term plan for managing dredged material from Pool 6.

Dredge material has many good uses, such as creating habitat and reinforcing existing infrastructure. The Corps also allows the public to access the material at certain sites at no cost. This use is termed “beneficial use.”

Maintenance dredging typically occurs at seven active dredge cuts in Pool 6. The annual average amount of material dredged in Pool 6 since 1981 is 25,000 cubic yards. Although a large capacity (1.3 million cubic yards estimated) will be dredged over 40 years, the amount of continuous “beneficial use” of the dredged material in Pool 6 allowed the Corps to develop a flexible DMMP that requires fewer real estate acquisitions, saving federal dollars.

Pool 6’s DMMP contains alternative plans that emphasize accommodating year-to-year placement rather than providing long-term storage capacity. The Corps selected a target year-to-year capacity of 168,000 cubic yards to provide ample space for the largest quantity of material likely to be dredged in one year.

The DMMP evaluated a list of potentially suitable sites and developed the Federal Standard or Base Plan for managing dredged material for a minimum of 20 years. The Federal Standard is defined as “the dredged material disposal alternative or alternatives identified by the Corps which represent the least costly alternatives consistent with sound engineering practices and meeting the environmental standards established by the [Clean Water Act’s] 404(b)(1) evaluation process…” (33 CFR 335.7).

Status

In fiscal year 2018, the Corps initiated planning for the Pool 6 DMMP and property acquisition under existing authorities.

A public meeting was conducted on February 21, 2019 presenting alternatives currently under consideration. The draft report will be released for public review and a public meeting will be held in early 2020. The U.S. Army Corps of Engineers, St. Paul District will evaluate and consider all public comments for the final DMMP. A final plan will be completed in spring 2020. Acquisition will be phased over time, pending prioritization of parcels and availability of funds.

Authority

Congress authorized the Upper Mississippi River 9-Foot Channel Navigation Project via the Rivers and Harbors Acts of 1930 and 1932.