Stormwater runoff is generated from rain and snowmelt events that flow over land or impervious surfaces, such as paved streets, parking lots, and building rooftops, and does not soak into the ground. The runoff picks up pollutants like trash, chemicals, oils, and dirt/sediment that can harm our rivers, streams, lakes, and coastal waters. To protect these resources, communities, construction companies, industries, and others, use stormwater controls, known as best management practices (BMPs). These BMPs filter out pollutants and/or prevent pollution by controlling it at its source.--EPA
To prevent pollutants from being washed or dumped into storm sewers, certain operators are required to obtain MS4 permits and develop stormwater management plans (SWMPs). The SWMP describes the best management practices (BMPs) that will be implemented to minimize the discharge of pollutants into the storm drain system.
NDOT was permitted as an MS4 in 2007. A Stormwater Management Plan was developed that documents stormwater management procedures and practices in six different program areas. Those program areas also referred to as minimum control measures (MCMs) are described below:
- NDOT Stormwater Management Plan
- NDOT MS4 Regulated Boundary Maps
- NDOT MS4 Annual Reports: 2018 | 2019 | 2020
MCM 1 & 2 – Public Education, Outreach and Involvement
NDOT conducts a number of educational efforts to inform its employees and the public it serves about stormwater. Education and outreach activities include the distribution of manuals, brochures, posters and newsletters, in addition to offering a number of training courses. The following links provide additional information related to stormwater education and outreach:
NDOT also engages the target audience in the process of developing and improving stormwater management practices and procedures. NDOT administrators meet on a regular basis to discuss stormwater efforts and to offer guidance and feedback for stormwater program managers and technical staff.
NDOT regularly participates in meetings that are open to the public, and, when appropriate, these meetings can be used as a venue to solicit input from the public regarding the Stormwater Management Program.
3 – Illicit Discharge Detection & Elimination
In general, illicit discharges include any discharge into a storm drain system that is not entirely composed of stormwater. The exceptions include water from firefighting activities and discharges from facilities already under an NPDES permit. Illicit discharges are a problem because, unlike wastewater, which flows to a treatment plant, stormwater generally flows to waterways without any additional treatment.
NDOT has developed an Illicit Discharge Detection and Elimination program with policies and procedures for identifying, enforcing, tracking and cleaning up illicit discharges within the storm sewer system. In addition, NDOT requires all applicable staff to receive routine training on identifying illicit discharges and the proper procedures for removal.
4 – Construction Stormwater Management
Uncontrolled stormwater runoff from construction sites can significantly impact rivers, lakes, and estuaries. Sediment in waterbodies from construction sites can reduce the amount of sunlight reaching aquatic plants, clog fish gills, smother aquatic habitat and spawning areas, and impede navigation.
The National Pollutant Discharge Elimination System (NPDES) stormwater program requires a stormwater permit for construction sites that disturb one or more acres of soil. Permitted sites are required to implement a Stormwater Pollution Prevention Plan (SWPPP) to manage stormwater runoff throughout the life of the project and to ensure vegetation is re-established before the permit can be closed.
NPDES Permit for Stormwater Discharges from Construction Sites
NDOT has developed a construction stormwater program to reduce pollutants in stormwater runoff from construction activities. Erosion and sediment control design, Stormwater Pollution Prevention Plans (SWPPPs), site inspections, certification training and contract administration procedures all help reduce the risk associated with disturbing soil during the construction process.
5 – Post Construction Stormwater Management
The goal of the Post Construction Stormwater Program is to minimize the discharge of potential pollutants in the highway's post-project stormwater runoff. NDOT accomplishes this by requiring Stormwater Treatment Facilities (STF’s) to be designed, constructed and maintained on new and redevelopment projects within MS4 areas. The stormwater treatment design process is described in Chapter 3 of the NDOT Drainage Design and Erosion Control Manual.
- Drainage Design and Erosion Control Manual, Chapter 3: Stormwater Treatment
- NDOT Stormwater Treatment Facilities – Maintenance Guides
6 – Pollution Prevention and Good Housekeeping
NDOT has created an operation and maintenance program with policies and procedures that minimize the impact of maintenance facility and highway facility operations on stormwater runoff. Staff members that operate and maintain maintenance facilities and the state highway system receive comprehensive environmental training.
For additional information regarding NPDES permits please visit the Nebraska Department of Environment and Energy website.