Minnesota Department of Transportation

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Project development

Environmental process | Environmental review | Stream or Water Body Modifications

Stream or Water Body Modifications process


Evaluating stream or water body modifications prevents impacts to fish and wildlife, potential problems such as erosion, bank instability (which can lead to erosion), aesthetic intrusion, flooding, and impediments to navigation.

Threshold criteria

Consider impacts on projects that have channel relocation, excavation, culvert installation or extension, bridge pier work, or any other activity that changes the course, current, or cross section of a stream or water body.  You do not have to use this guidance for centerline or ditch culverts primarily conveying storm water within highway right of way.  See the TPDP Wetlands section for information on addressing impacts to wetlands.

Assess the need for channel modification and the associated permits during the environmental process while addressing impacts.  Always consider alternatives that avoid channel changes.  Discuss mitigation measures to the extent possible.

The design study should refine the design concept(s) developed earlier.  Make mitigation refinements.  You can make an assessment during preliminary design to see if the project requires a Section 404/Section 10 permit or Minnesota Department of Natural Resources (MnDNR) Work in Public Waters Permit.  If a General or Nationwide 404/Section 10 permit applies, you will not need the individual permit.  You will typically obtain the MNDNR Public Waters and US Army Corps of Engineers (USACE) Section 404/Section 10 permits during final design.

Ensure that permanent construction features reducing or eliminating negative impacts are incorporated into project design during the final design phase.  You will normally obtain required permits at this stage.  You may include excerpts from the final design plans with the permit applications to satisfy the permitting agencies that special mitigation features are part of the project.  Final design ensures that the plans, specifications, and estimate (PS&E) package include all mitigation comments.

Class I Actions (Environmental Impact Statement (EIS) Projects)

Conduct an early assessment of the magnitude of potential impacts and assess the need for further study.  Include information about potential impacts of the various alternatives at the public hearing.

Draft EIS (DEIS)

Conduct an inventory of potential impacts for project alternatives.  Contact the USACE, United States Fish and Wildlife Service (USFWS), US Coast Guard (USCG), Minnesota Pollution Control Agency (MPCA), and the MNDNR to determine the level of agency interest.

Final EIS (FEIS)

Include the specifics of mitigation measures in the FEIS.  Include the letters of coordination/concurrence from United States Fish and Wildlife Service (USFWS), United States Army Corps of Engineers (USACE), and the United States Coast Guard (USCG).

Class II Actions (Categorical Exclusion (CATEX) Projects)

Assess potential impacts and discuss mitigation measures if appropriate.  Clearly state whether or not there is any change to the course, current, or cross section of any stream or water body.

Class III Actions (Environmental Assessment (EA) Projects)

Conduct an inventory of potential impacts for project alternatives.  Contact USACE, USFWS, USCG, MPCA and MNDNR to determine the level of agency interest and include letters of coordination/concurrence with the environmental documentation.

Agencies involved

Consultation with the USFWS is necessary for any federal action that requires impoundment (surface area of 10 acres or more), diversion, channel deepening, or other modification of a stream or water body according to the Fish and Wildlife Coordination Act.     

Consultation with MNDNR and obtaining permits from them is a requirement for any action that changes or diminishes the course, current, or cross section of public waters by any means, including filling, excavating, or placing materials in or on the beds of public waters according to the Work in Public Waters, Minnesota Statutes 103G.245.

Dredge and fill or excavation activities require a USACE Section 404 permit under the Clean Water Act.  For navigable waters, dredge and fill activities require coordination with the USCG and may require a permit from USACE according to the River and Harbors Act of 1899.


The following permits apply to stream or water body modification: