Case Study: Duluth-Superior Harbor Dredged Material Management Plan

Duluth-Superior Harbor Dredged Material Management Plan


Policy-makers say it. Sportsmen say it. Environmental advocates say it. Everyone connected to the Great Lakes says it one time or another. “Lake Superior is different. Lake Superior is unique.” And to see how true this is, all one needs to do is look at all of the programs and initiatives that seek to preserve the water quality of Lake Superior or reduce the pollution going into the lake. With all of the attention focused on protecting Lake Superior, it should come as very little surprise that there are many stakeholders and many opinions regarding the dredging strategy for the Duluth-Superior Harbor.

The U.S. Army Corps of Engineers (USACE) completed a Dredged Material Management Plan (DMMP) for the Duluth-Superior Harbor in April 1999. For six years, state agencies, local governments, and the Seaway Port Authority of Duluth reviewed the plan and responded to the Corps of Engineers about different alternatives available to manage a projected 3 million cubic yards of material over the next 20 years. Through those years, one central question remained the focus. How to keep the navigation channels for the largest tonnage Great Lakes port maintained in a cost-effective manner while adhering to the policies and goals developed to protect this resource? To answer this question, the stakeholders have put their trust in communication, creativity and commitment.

No more room at Erie Pier

Since 1979, a large majority (90%) of dredged material from the Duluth-Superior Harbor has been placed at the Erie Pier Confined Disposal Facility (CDF). Erie Pier was built like many other CDFs in the Great Lakes under Public Law 91-611 in the late 1970s. Although initially designed to last for ten years and store only 1 million cubic yards of material, Erie Pier has lasted twice as long and stored twice as much material primarily through raising of the dikes and the recycling of the material for construction projects. Nevertheless, Erie Pier is finally reaching its capacity and the USACE needed to develop a management plan to provide for future dredging and disposal. That management plan is formally known as the Duluth-Superior Harbor Dredged Material Management Plan (DMMP).

Development of the DMMP

Every port that needs long-term navigational dredging is required to have a DMMP. The DMMP identifies the dredging needs for a period of 20 years and method(s) for management of the dredged material. Under current regulations and procedures, a DMMP’s Base Plan needs to adhere to the “Federal Standard” (33CRF335.7). These regulations clearly state that the USACE must select those alternatives that are the least costly, use sound engineering principles, and meet the environmental standards outlined in Section 404(b)(1) of the Clean Water Act. In the case of Duluth-Superior Harbor, the USACE-Detroit District indicated from the beginning of the DMMP process that the Corps needed to develop a Base Plan consistent with the Federal Standard.

As the development of the DMMP proceeded, it was evident that the Corps was going to recommend management alternatives that included open water disposal of dredged material. The open-water alternative included filling in six deep holes in the St. Louis Bay-harbor area. Although these holes were not natural, they were recognized as important fishery and benthic habitats and the States of Minnesota and Wisconsin opposed the filling of them. While open-water disposal was common up until the 1960s across the Great Lakes, its use has decreased. Because Minnesota and Wisconsin are concerned with protecting aquatic habitat, the states developed enforceable policies that prohibit the in-water disposal of dredged material unless it is part of a beneficial use project. The deep holes alternative proposed by the Corps of Engineers did not have any beneficial use component.

An impasse seemed apparent as both states indicated they would not be able to issue a Clean Water Act Section 401 water quality certification to the USACE for the deep hole alternative. Should USACE determine the deep hole alternative to be the Base Plan, a delay in maintenance dredging of the harbor could occur once the remaining available space in Erie Pier CDF was filled, unless the Corps and the states could come to an agreement for implementation of another dredged material management alternative.

Exploring Beneficial Use Alternatives

As development of the DMMP proceeded, there was growing interest among the states to incorporate beneficial use alternatives into the Base Plan. Those alternatives included habitat creation, mineland reclamation, beach nourishment, and developing Erie Pier into a dredged material recycling station. The Corps recognized the importance of protecting Lake Superior and was supportive of advancing beneficial use alternatives. However, regulations prevented the Corps of Engineers from incorporating most of these alternatives into the Base Plan except for beach nourishment because they did not represent the least costly alternatives. Other alternatives could be pursued but extra costs may be subject to a cost share between the federal government and the local sponsor (in this case, the Seaway Port Authority of Duluth).

Although the DMMP process began to shift more toward beneficial use, the states remained frustrated. The Port Authority was naturally concerned about the local match, while the state natural resources and environmental agencies questioned how federal regulations regarding dredged material management could in some instances contradict the objectives and the goals of many federal and international programs designed to protect the Great Lakes such as the Great Lakes Initiative.

USACE Signs the DMMP with Changes

In April 1999, after the stakeholders reviewed and commented on the Draft DMMP, the USACE issued a public notice that the DMMP had been signed. The Corps stated that the Base Plan (which included the deep hole alternative) would “be used only for the purpose of establishing the Federal baseline costs for future dredging and placement activities at Duluth-Superior Harbor.” The gist of this public notice was that the USACE would not pursue the deep hole alternative. However, the Corps would not have to spend any more money on dredging and disposal in the Duluth-Superior Harbor than they would have if the deep hole alternative had been implemented. The USACE also stated in the public notice that they would further pursue a habitat creation project at the 21st Ave. West Channel in St. Louis Bay. This habitat creation project would qualify for funding under Section 204 of The Water Resources Development Act of 1992 and subject to a 25% local match. The states are beginning to work together to find that funding, estimated to be $400,000. Therefore, if the habitat creation project is constructed, then the three alternatives for managing dredged material for the next twenty years will be:

  1. Continued Use of Erie Pier until full (2-5 years)
  2. Beach Nourishment (5 years)
  3. Habitat Creation at 21st Ave West Channel (10 years)

Also, the USACE and the states are committed to pursuing other beneficial use alternatives especially processing material at Erie Pier for construction and other purposes and using dredged material for mineland reclamation in taconite tailing basins on the Minnesota Iron Range.

Communication + Partnerships = Success

One factor that has made the DMMP process in the Duluth-Superior Harbor special and unique is the level of communication and the commitment toward cooperation. The Duluth-Superior Harbor Technical Advisory Committee (HTAC) has met quarterly for the last fifteen years to discuss maintenance dredging, the maritime industry, and need for environmental protection in the Duluth-Superior Harbor. It was through the HTAC meetings that an open communication link between the states and the USACE was nurtured.

Another effective tool that has produced favorable results is the Duluth-Superior Harbor Partnering Agreement; a document signed by the key stakeholders. Initiated by the USACE-Detroit District in 1996, this document outlines each state agency’s commitment to preserving the maritime industry, protecting the environment and resolving differences in a cooperative spirit. The Partnering Agreement also asks signatories to make a financial contribution to support the development and implementation of a work program. In 1998, $25,000 was raised allowing a regional planning agency to better facilitate the DMMP process as well as write harbor-related plans.


Lake Superior is a special and unique freshwater resource. It took six years to develop a dredging strategy for the Duluth-Superior harbor with significant give and take among stakeholders. The protracted planning process and contentiousness of the issues matched what was at stake. The implementation of the current DMMP will provide for appropriate maintenance dredging while protecting Lake Superior and the St. Louis River. Stakeholders have learned that the sun is setting on the old days of maintenance dredging and disposal and that cooperation and creativity often produces the best-possible results.

Note: This case study was prepared during the summer of 1999.

For Further Information

Andrew Bramson
Transportation Planner
Arrowhead Regional Development Commission
221 West 1st Street
Duluth, MN 55802
Phone: 218-529-7528