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Stormwater

INDOT and Stormwater Management

INDOT maintains almost 29,800 lane miles of highways, Operation and Maintenance Facilities, Welcome Centers and Rest Areas, and approximately 1,500 construction projects per year. This amount of impervious surface and construction activity can pose unique challenges for stormwater management.  Stormwater runoff is a major contributor to water pollution nationwide and one of the great challenges of stormwater management.

Day-to-day travel and activities on roadways can impact stormwater management, resulting in stormwater pollution but can also affect drainage:

  • Litter tossed or blown out of vehicles
  • Leaking oil or other fluids from vehicles
  • Heavy metals from brakes and engine wear
  • Salt and other winter weather treatments
  • Spills from traffic accidents
  • Construction activities
  • General facility usage and road maintenance

Construction Stormwater General Permit (CSGP)

The CSGP is a performance-based regulation designed to reduce pollutants that are associated with construction and/or land disturbing activities. A CSGP is required for construction activity (which includes clearing, grading, excavation and other land-disturbing activities) that results in the disturbance of one (1) acre or more of total land area. INDOT permits and manages anywhere between 100 to 150 CSGPs annually.  Additionally, INDOT is responsible for managing stormwater control measures for all projects, not just those with CSGP.

For more information about the CSGP go to IDEM’s website here.

For questions about permitting a CSGP for INDOT State Projects or Stormwater Management Design or Construction Standards contact the INDOT Stormwater Team at CSGP@indot.in.gov

Post-Construction Stormwater Management (PCSM)

INDOT's Municipal Separate Storm Sewer System General Permit (MS4GP) and the transition from Rule 5 (327 IAC 15-5) to the CSGP in 2021 requires INDOT to address discharges of post-construction stormwater run-off from new development and redevelopment. As areas develop and impervious surfaces increase, the stormwater velocity, quality, and types of pollutants exposed to stormwater can change and increase. INDOT has a requirement to provide Post-Construction Best Management Practices (PCBMPs), where applicable, to reduce pollutants and downstream impact from roadways and new facilities. The following are guidance documents and resources that show how INDOT is addressing PCSM and stormwater quality.

For questions about INDOT’s Post-Construction Stormwater Management program contact the INDOT PCSM Team at PCSM@indot.in.gov.

Design Memorandum 22-22 Post-Construction Stormwater Management
Post-Construction Stormwater Management Guidance 7-3-2024
PCSM Quick Facts

Resources
Inspection and Maintenance Plan Templates

INDOT Construction Stormwater Management Training

This training introduces participants to Erosion and Sediment Control regulations and practices.  This training is designed for Stormwater Quality Managers and others inspecting INDOT projects but can be taken by anyone interested in learning more about INDOT Stormwater Management.

For more information about the course, registration, renewals, and active status please visit the training course information page here.

Municipal Separate Storm Sewer System General Permit (MS4GP)

INDOT has been recognized as a Municipal Separate Storm Sewer System (MS4) and is required to create goals to reduce its impact on stormwater pollution. The requirements of the MS4GP influence nearly every aspect of INDOT’s operations, from construction projects and their design, operation and maintenance of facilities, employee education, and beyond.

INDOT is required to submit a Stormwater Quality Management Plan (SWQMP) and an Annual Report to IDEM. These are required to show INDOT is working toward the goals in the MS4GP to help protect Indiana’s stormwater run-off from INDOT’s roadways and construction projects.

For more information about the MS4GP go to IDEM’s website here.

For further information about INDOT’s MS4 Program please contact stormwater@indot.in.gov.

SWQMP Annual Reports

Supplemental Resources

See Something, Smell Something, Say Something

Help INDOT find drainage concerns or pollution in our right-of-way by reporting a concern to INDOT4U so we can improve the safety for our traveling public and environmental health across the State of Indiana.

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