US Army Corps of Engineers
St. Paul District

Projects

Dredged Material Management Plan (DMMP): Lower Pool 4

Published March 15, 2018
Updated: Sept. 19, 2019
Location
Dredged Material
Management Plan
website

The Lower Pool 4 Dredged Material Management Plan (DMMP) study area is located between Lock and Dam 4 and the foot of Lake Pepin, river miles 753.0 to 764.0. The study area includes the Minnesota communities in Wabasha County of Lake City, Wabasha, Reads Landing and Kellogg and the Wisconsin communities in Buffalo and Pepin Counties of Nelson, Alma and Buffalo City.

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 Lower Pool 4. Permanent dredged material placement sites previously used in Lower Pool 4 have nearly reached capacity. Relying totally on existing island transfer sites cannot be considered the least cost alternative, because material placed at island transfer sites will need to be offloaded to permanent sites resulting in double handling of material. Additional permanent sites are needed to accommodate dredging needs in Lower Pool 4.

Maintenance dredging has occurred at six active dredge cuts in Lower Pool 4. These cuts are expected to generate on average about 270,000 cubic yards of dredged material annually or 10.7 million cubic yards over the next 40 years. As a major tributary of the Upper Mississippi River, the Chippewa River enters Lower Pool 4 at river mile 763.5 and carries a very high sediment load. This load contributes to Lower Pool 4 generating more dredged material than any other pool in the St. Paul District.

The DMMP includes an evaluation of potentially suitable sites, which will develop into 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 C.F.R. § 335.7).

Status

In 2017, a draft DMMP was released to the public for a 30-day public comment period and extended for a total of 105 days for public review.

In 2018, the Corps completed evaluation of alternatives from the public comment period and continued to engage stakeholders. A memorandum of agreement was signed in June 2018 with the city of Wabasha to work in collaboration on a solution, including the possibility of a private/public partnership. Based on this engagement and coordination, the Corps has rewritten the draft report, requiring a new public review period that is planned for spring 2020. A final plan and subsequent real estate acquisition are anticipated in fiscal year 2020 and 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 by the Rivers and Harbors Acts of 1930 and 1932.