Understanding Highway Stormwater Runoff

Stormwater runoff occurs when water from rain or snowmelt flows over the ground. Stormwater can pick up pollutants such as oil, grease, chemicals, nutrients, metals and bacteria, and flow into stormwater systems or directly to the lake, streams, rivers or wetlands. The management of stormwater runoff is at once a simple concept and a complex problem. Precipitation runs off impervious surfaces rather than infiltrating naturally into the soil. The cumulative impact resulting from the increased frequency, volume, and flow rate of stormwater runoff events can lead to destabilization of downstream channels and can also result in increased wash-off pollutant loading to receiving waters.

Precipitation runoff from construction and land disturbance activities are also considered Stormwater Runoff, including: clearing, grading, excavation, stockpiling of fill material and other activities, which expose soil related to projects that build, expand or replace or demolish something (such as a home, a store, a golf course, a road, etc.). The U.S. Environmental Protection Agency (EPA) does not include routine earth-disturbing activities that are part of the day-to-day operation of a completed facility, such as landscape maintenance or the grading of existing gravel roads.

The EPA and State of Vermont Agency of Natural Resources offer informative web sites:

Other useful and informative links include: