Dredged material is material excavated at or below the ordinary high water level of waterbasins, watercourses, public waters, or wetlands (defined in Minn. Stat. 103G.005). For example, sediment might be dredged from lake or river bottoms to accommodate shipping traffic in a commercial port or recreational boating in a marina.
Dredged material can affect the environment. Carriage water and hydrostatic water from hydraulic or mechanical dredging processes, and stormwater runoff from sites where dredged material is stored or managed, can cause harm if it reaches surface water or groundwater. The type of dredging operation, its location, and contaminants in the dredged material will determine how the MPCA regulates the project.
The Department of Natural Resources regulates dredging activities, but dredging work is subject to the MPCA's water quality standards (see Minnesota Rules chs. 7050, 7060 and 7090). The MPCA also reserves the right to require a permittee to obtain an individual NPDES/SDS permit for dredging activity.
If your project involves dredging a stormwater pond, please see the "Stormwater sediment removal projects" section at the bottom of this page.
Do I need a permit?
- The MPCA may require a State Disposal System (SDS) permit for storing, treating, disposing, or reusing dredged materials on land in Minnesota, if the material was dredged from navigational channels, harbors, docks and marinas, and similar projects in the following areas:
- Mississippi River downstream of River Mile 857.6 (near the Soo Line Rail crossing near St. Anthony Parkway in Minneapolis)
- Minnesota River downstream of River Mile 27 (about two miles upstream of the CSAH 101 crossing in Shakopee)
- St. Croix River downstream of River Mile 26 (about three miles upstream of the East Chestnut St. crossing in Stillwater)
- St. Louis River downstream of the State Hwy 23 crossing
- St. Louis Bay or Duluth/Superior Harbor
- Out-of-state projects
- If the dredge project is in the areas listed above, a permit is required for volumes greater than 3,000 cubic yards that will be stored or reused.
- If the project is not located in the areas above or the material (at any volume) will going to a landfill with an MPCA permit that covers the management of dredged material, no permit is required.
For more, look at this guidance (see the decision flow chart for permitting dredge projects on page 4):
Projects that don't need permits
The MPCA recommends that unpermitted projects follow guidance and best management practices, including submitting the notification form below at least 30 days before the start of dredging. The MPCA reserves the right to require a permit for any dredge material disposal or reuse if necessary to protect the environment. The MPCA is unable to provide additional technical assistance for projects not requiring a permit.
Projects needing permits
Permits issued for specific projects or site activities are unique to the project and provide specific terms and conditions that must be met. The permit application will require descriptions of:
- The dredge project and any management area(s)
- The status of the receiving water
- What pollutants may be in the material
The MPCA will use these factors to determine the appropriate pollutant limits and monitoring. If your non-stormwater project requires permit coverage, submit these forms at least 180 days prior to beginning excavation:
Permitted projects must submit an annual report describing the disposition of the dredged materials.
Management of dredged material
Information on required sampling and analysis, permits, and management for dredged material:
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In general, dredged material may be disposed
- at a permitted solid waste facility
- through permitted on-site disposal
- by use or reuse for a beneficial purpose, including fill
Dredged materials may be placed at a short-term location during off-loading or rehandling activities, stored temporarily for dewatering prior to reuse, or stored long-term before final disposal, at the dredge project site or elsewhere. See your permit or chapter 5 of the management guidance above for ways to protect the material from contaminating stormwater.
Management levels for use/reuse
Dredged material is assigned a management level based on sediment characterization (analyzing the type and level of pollutants), which dictates its appropriate disposition:
- Level 1: Suitable for use or reuse on properties with a residential or recreational use category
- Level 2: Suitable for use or reuse on properties with an industrial use category
- Level 3: Contact MPCA staff for information on disposal requirements
Larger projects may produce dredge materials with different management levels. The material may be
- Separated and managed according the relevant management level
- Managed at the most restrictive management level, if separation is not feasible or the types are co-mingled prior to disposal
Table 5 in Chapter 5 of the management guidance specifies the soil reference values that are acceptable within each management level.
Other environmental approvals
In addition to the water quality concerns for dredged material, other environmental permitting or oversight may be required. Review the list below and obtain all applicable approval before beginning dredging activities.
US Army Corps of Engineers
The MPCA is not authorized to issue NPDES permits for discharges of dredged or fill material from dredge activities [40 CFR 122.3 (b)]. The US Army Corps of Engineers' (USCOE) Regulatory Programs include Section 10 of the Rivers and Harbors Act of 1899 and Section 404 of the Clean Water Act. The St. Paul District's regulatory jurisdiction covers the states of Minnesota and Wisconsin.
If a federal permit is needed for activities that may result in a discharge into U.S. waters, the permittee must also obtain a Section 401 water quality certification. In Minnesota, the MPCA administers the 401 Certification Program.
Minnesota Department of Natural Resources
Projects affecting the course, current, or cross-section of some water bodies may require a Public Waters Work Permit from the Minnesota Department of Natural Resources.
Environmental review looks at how a proposed project could potentially affect the environment and ways to avoid or minimize impacts before the project is permitted and built. Environmental review can be a one or two-step process: The shorter, less detailed Environmental Assessment Worksheet (EAW) or the longer, more complex and detailed Environmental Impact Statement (EIS). Go to the Environmental Quality Board or MPCA's Environmental review program web pages for more information.
Stormwater sediment removal projects
Refer to the modified approach for dredging urban stormwater facilities in Chapter 4 and the MPCA Stormwater pages for more information about other types of stormwater permits. All stormwater sediment removal projects that disturb one or more acres of soil as a result of sediment stockpiling, use, or reuse must obtain a NPDES/SDS construction stormwater permit unless otherwise exempted. Updates to the sediment removal guidance in 2012 included three main changes:
- Permits are not required when performing routine maintenance on stormwater conveyance and collection systems
- You don't need to notify the MPCA of sediment removal activities. The agency recommends that you keep records on sediment removal projects, including who did the removal, how much was removed, test results to characterize the waste, disposal location, and the date of sediment removal and disposal
- Revised BMPs include guidance from cities with experience doing sediment removal projects
This video offers some highlights of Minnesota's stormwater sediment removal guidance.