Environmental for Engineers

Environmental Clearance is required for every project, adhering to the National Environmental Policy Act (NEPA). For additional details, use the link below to the Environmental Program website and/or discuss with your resource specialist. NEPA took effect January 1, 1970, and is implemented by the Federal Council on Environmental Quality. This is a law enabling transportation officials to make project decisions that balance environmental factors with engineering and transportation needs.

NEPA requires a project to follow one of three paths to obtain environmental clearance: Categorical Exclusion, Environmental Assessment, or Environmental Impact Statement. A majority of our projects are Categorical Exclusions, which culminate in a signed CDOT Form 128 before Advertisement. The Form 128 documents the analysis done for the many individual environmental resources. More information for the Environmental Assessment and Environmental Impact Statement processes can be found in CDOT's NEPA Manual, linked to on the right side of this page.

More detail on each of the individual environmental resource areas listed below is in the “Clearance Processes for Environmental Resources” table in the “Manuals and Other References” box on the right side of this page. Each of these may be evaluated in order for the project to obtain environmental clearance.

  • Air Quality
  • Noise Analysis
  • Hazardous Materials
  • Threatened and Endangered Species
  • Migratory Birds
  • Wetlands
  • Paleontology
  • Historic Properties
  • 4(f)
  • 6(f)
  • Social Resources
  • Farmland
  • Floodplains
  • Noxious Weeds
  • Senate Bill 40
  • Water Quality
  • Stormwater Management Plans