Stormwater runoff from construction activities can have a significant impact on water quality. As stormwater flows over a construction site, it picks up pollutants like sediment, construction debris, and chemicals such as gas, fertilizer, and paint. Polluted stormwater runoff can harm or kill fish and other wildlife. Sedimentation can destroy aquatic habitat and high volumes of runoff can cause stream bank erosion.

Prior to obtaining a City of Thornton construction permit from City Development, the owner/contractor must obtain a Colorado Department of Public Health and Environment Stormwater Discharges Associated with Construction Activity Permit Application.

Under current regulations, this permit application covers construction sites disturbing one or more acres that include construction activities such as clearing, grading, excavation, and other ground disturbance activities.

Please click on the link below to access the Colorado Department of Public Health and Environment's website where more information can be obtained

Colorado Department of Public Health and Environment

The City of Thornton has composed its NPDES Phase II program in conjunction with the States Rules and Regulations.

Plesase click on the links below for the specific detail you are looking for.

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Thornton Concrete Truck Washout Detail

Thornton Storm Sewer Manhole Cover Detail

Thornton Standard SWMP Erosion Control Notes

Please direct any questions pertaining to this program to the Infrastructure –Engineering Services by calling 720-977-6256.