Minnesota Department of Transportation

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Project development

Environmental process | Environmental review

Stream or Water Body Modification


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, and flooding, and cause impediments to navigation.

When to use this subject

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.

How this subject fits into the overall project development process

Assess the need for channel modification and the associated permits during the environmental process while addressing impacts in the scoping phase. 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. If a General or Nationwide 404/Section 10 permit applies, you will not need the individual permit. You will typically obtain the Minnesota Department of Natural Resources (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.

Organizations involved