Stormwater Management Program

When rain events occur they produce what is called stormwater runoff, which is the water that falls during a rain event that cannot be absorbed (infiltrate) into the ground and starts moving across your lawn, driveway, parking lot, or highway. As stormwater runoff moves across a surface, it picks up and transports whatever is in its pathway and generally deposits it in nearby streams, rivers, and lakes. This means that stormwater runoff can transport non-desirable items or pollutants into streams, rivers, and lakes.

Click image for copy of TDOT's TS4 Permit

As a recipient of a National Pollutant Discharge Elimination System (NPDES) permit from the Tennessee Department of Environment and Conservation (TDEC), TDOT is responsible for the management of stormwater runoff from its more than:

15,000 miles of highways and
190 facilities throughout the state.

TDOT’s highways and facilities throughout the state are collectively referred to as the transportation separate storm sewer system or TS4 This is why TDOT’s NPDES permit is commonly referred to as a TS4 permit and not the traditional MS4 designation for municipalities (cities and counties).

TDOT’s Stormwater Management Program consist of six (6) main components. Please use the links below to learn more about TDOT’s approach to stormwater management.

TDOT Stormwater Management Program Components

Education and Outreach