Importance of Missouri Waters

In Missouri, our surface water and groundwater resources are critical for the economic, health and well-being of our citizens.  Stormwater has the potential to carry pollutants from MoDOT's right-of-way into streams, rivers, and lakes.  MoDOT has developed a Stormwater Management Program to reduce pollutants in stormwater from MoDOT's roadways and facilities. 

Use the Explore This Topic to the left and the links below to review MoDOT's Stormwater Program components. 

National Pollutant Discharge Elimination System (NPDES)

Missouri Department of Transportation (MoDOT) is regulated under a National Pollutant Discharge Elimination System (NPDES) general, statewide operating permit that requires MoDOT to develop and implement a comprehensive program to reduce pollution, to the maximum extent practical, that discharges to surface waters resulting from stormwater runoff.

MoDOT requested a single NPDES Municipal Separate Storm Sewer System (MS4) permit for stormwater discharges from all MoDOT properties, facilities, and activities including construction. The Missouri Department of Natural Resources issued a modified Transportation Separate Storm Sewer System (TS4) permit on November 1, 2019.

MoDOT has developed a Stormwater Management Program (SWMP) to comply with the Permit requirements and address stormwater pollution related to highway planning, design, construction, and maintenance activities throughout the state.

Provisions of the Federal Clean Water Act and related state rules and regulations require a municipal separate storm sewer system (MS4) permit within communities designated as urbanized areas (UA), serving a population density of 50,000 people or more, or are located outside an urbanized area serving a jurisdiction with a population of at least 10,000 and a population density of 1,000 people per square mile or more. Furthermore, a municipal separate storm sewer means a conveyance or system of conveyances including roads and highways with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, paved or unpaved channels, or storm drains designated and utilized for routing of storm water. MoDOT has an MS4 individual permit developed specifically for a transportation agency, also known as a Transportation Separate Storm Sewer System Permit (TS4) , obtained from the Missouri Department of Natural Resources (MDNR), delegated by the Environmental Protection Agency (EPA). It requires MoDOT to develop and adhere to a Storm Water Management Plan (SWMP) comprised of six minimum control measures (MCMs).