The purpose of the Dredged Material Management Plan (DMMP) is to prepare a coordinated long-term plan for managing dredged material from Lower Pool 4.
The Lower Pool 4 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.
The U.S. Army Corps of Engineers operates and maintains the Upper Mississippi River 9-Foot Channel Navigation Project. 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.
Maintenance dredging has occurred at six active dredge cuts. 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).
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 rewrote the draft report, and completed a public review on it in summer 2022. The final plan was completed in spring of 2023. Implementation of the plan is underway. A unique partnering opportunity with Wabasha, Minnesota, referred to as Section 217 was signed in summer 2023. Real estate acquisitions will be phased over time, pending prioritization of parcels and availability of funds.
Congress authorized the Upper Mississippi River 9-Foot Channel Navigation Project by the Rivers and Harbors Acts of 1930 and 1932.
Expended to date $5,271,500