Project Information

Planning & Design

Protecting water quality is an important part of the transportation planning process. CDOT has a process to consider and plan for all new highways or highway expansions. Water quality impacts are considered during several steps in the process. Depending on the extent of the project, one of several levels of environmental analysis can be conducted - categorical exclusion, environmental assessment, and environmental impact statement. Click here to learn more about CDOT's environmental analysis process.

Potential for impacts to water quality is evaluated in each type of environmental analysis. During the planning phase of a project, CDOT evaluates if permanent water quality should be installed and develops a stormwater management plan (SWMP). SWMPs help the construction site team protect water quality by describing site information, control measure (CM) locations, narratives, and details, and other important project information.

Seeding & Blanket

CDOT’s Erosion Control and Stormwater Quality Guide can be used to help project personnel select temporary and permanent control measures during design and through the construction of a project.


Once the project is planned and designed, it moves to the construction phase. If the construction site will disturb one acre or more, CDOT will request a stormwater construction permit from CDPHE. CDOT’s Water Quality Program and CDPHE’s permit requirements ensure that CDOT construction sites minimize contribution to stormwater pollution.