The purpose of the Dredged Material Management Plan (DMMP) is to prepare a coordinated long-term plan for managing dredged material in Pool 2. This plan was initiated due to increases in dredging volumes throughout Pool 2. Furthermore, three temporary dredged material placement sites need to be excavated in Lower Pool 2.
The Pool 2 DMMP study area is located between Lock and Dam 2 near Hastings, Minnesota, and extends upstream to Lock and Dam 1, from river miles 815.2 to 847.7, respectively. The study area includes Upper Pool 2, which is situated in the urban area of Minneapolis and St. Paul, Minnesota.
The U.S. Army Corps of Engineers operates and maintains the Upper Mississippi River 9-Foot Channel Navigation Project, and one method the Corps uses to keep the channel the authorized width and depth is dredging river soils or “material.”
Pool 2 has been experiencing higher flows due to rainfall and water runoff. As a result of more sediment, Pool 2 now requires additional dredging. Between 1981 and 2014, the average amount of material dredged per year in Pool 2 was approximately 107,000 cubic yards. The Corps’ September 2016 sediment assessment predicted future dredging requirements throughout Pool 2 to increase substantially, to approximately 169,000 cubic yards per year. Therefore, the 40-year target capacity for the Pool 2 DMMP is approximately 6.8 million cubic yards.
The DMMP identified potential suitable sites for the Federal Standard or Base Plan for managing dredged material over the next 40 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).
In July 2020, the Corps finalized the Pool 2 DMMP and started the federal acquisition process for the preferred permanent upland placement site of dredge material at Lower Grey Cloud Island. Currently, discussions continue between St. Paul District and the property owners for the acquisition of the property.
Congress authorized the Upper Mississippi River 9-Foot Channel Navigation Project via the River and Harbor Act of 1930.
Expended through August 2022 $1,398,748