Minnesota Department of Transportation

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Project development

Environmental process | Environmental review

Water Quality


The purpose of addressing water quality (WQ) is to protect streams, lakes and wetlands from degradation of WQ.

When to use this subject

Use this guidance to address potential impacts to surface waters such as runoff and physical alterations. The WQ section primarily addresses post-construction runoff and permanent physical alterations of waters. Use the guidance for Erosion Control for construction-related impacts.

Address WQ issues whenever a project adds new sources or additional water to existing water sources in the project area. Also address WQ issues for bridge construction and drainage modification near sensitive water bodies since they will raise WQ issues.

Certain surface waters that require special consideration include calcareous fens, designated outstanding resource value waters, designated trout streams, trout lakes, and listed impaired waters.

Sensitive water bodies generally require special attention and early coordination. New construction and drainage modifications directing new or additional highway runoff to lakes, streams, and wetlands are also a concern. Consult with Office of Environmental Stewardship (OES) on any project with sensitive water bodies such as designated trout streams, trout lakes, calcareous fens, or outstanding resource values waters. These receive highway runoff and need special attention and coordination.

In addition to the above concerns, projects that increases impervious surfaces (such as added lanes, wider paved shoulders, etc.) initiate WQ concerns that will need examination.

The project may require volume control, ponding or other treatment of discharged stormwater. If so, consult with OES and the District Hydraulics/Water Resources Unit.

New WQ non-degradation rules may require additional evaluation of WQ impacts for all waters.

How this subject fits into the overall project development process

Start coordination early. Ensure that you incorporate all mitigation commitments into the plans, specifications, and estimate (PS&E) package during final design.

Organizations involved