Managing the Environmental & Project Development Process

1. Stormwater Management Managing the Environmental & Project Development Process

2. Regulations • Federal Water Pollution Control Act (Clean Water Act) • National Environmental Policy Act (NEPA) • ORC Chapter 6111 (Water Pollution Control) • Ohio EPA National Pollutant Discharge Elimination System (NPDES) Permits • Construction General Permit (CGP) • Watershed Specific CGP Managing the Environmental & Project Development Process

3. Stormwater Pollution • Primary Pollutants • Sediment • Heavy Metals • Oil & Grease • Solids • Salt • Sources • Brake dust, tire wear, fluids • Litter • Construction • Maintenance Activities • Atmospheric Deposition Managing the Environmental & Project Development Process

4. Stormwater Regulations • Permits • Construction General Permit • Watershed Specific Permit(s) • Administered by OEPA • Earth-disturbing activities > 1 acre • Primary Requirements: • Temporary sediment and erosion controls during construction • Post-construction stormwater management controls after construction (permanent) Managing the Environmental & Project Development Process

5. ODOT Responsibilities • Stormwater Management Plan • Required for ODOT’s “MS4” Stormwater Permit • Reduce the discharge of pollutants from ODOT’s storm sewer system • Minimum Control Measures (MCM’s) • MS4 = Municipal Separate Storm Sewer System Managing the Environmental & Project Development Process

6. NPDES Stormwater Regulations & ODOT Responses • Supplemental Specification 832 • Temporary sediment and erosion control during construction • L&D Manual, Vol. 2 Drainage Design • Post construction stormwater management controls (after construction -permanent) Managing the Environmental & Project Development Process

7. NPDES Post-Construction Stormwater Management • Required to Treat: • Water Quality • Remove pollutants • Water Quantity • Amount of stormwater that enters a stream • Challenge • Comply with permit requirements • Fit into linear project footprint • Limited ability to acquire right of way Managing the Environmental & Project Development Process

8. NPDES Post-Construction Stormwater Management • ODOT BMP Toolbox • Vegetated Filter Strip • Vegetated Biofilter • Manufactured Systems • Extended Detention • Retention Basin • Infiltration Techniques • Bioretention Cell • Constructed Wetlands Managing the Environmental & Project Development Process

9. NPDES STORMWATER Post-Construction Stormwater BMPs • Vegetated Filter Strip • Vegetated portion of the graded shoulder • Vegetated foreslope • Vegetated Biofilters • Vegetated portion of the • graded shoulder • Vegetated slope • Vegetated ditch Managing the Environmental & Project Development Process

10. NPDES STORMWATER Post-Construction Stormwater BMPs • Manufactured Systems • Proprietary underground structure • Offline configuration with existing storm sewer • Removes particulate matter through settlement or other means • NOTE: There are many different types of manufactured systems from a variety of companies Managing the Environmental & Project Development Process

11. NPDES STORMWATER Post-Construction Stormwater BMPs • Extended Detention • “Dry pond” • Captures storm water during rain events and slowly releases the entire captured volume over a period of time leaving a dry bottom • Retention Basins • “Wet pond” • Has a minimum water surface elevation between storms that is defined as the permanent pool. • Captures storm water during rain events and slowly releases the captured volume over a period of time. Managing the Environmental & Project Development Process

12. NPDES STORMWATER Post-Construction Stormwater BMPs Infiltration Techniques • Storm water filters through substrate consisting of soil, sand, or gravel • Discharges treated storm water into ground water rather than into surface waters Bioretention Cells • Depressed, low-lying areas that treat storm water through evapotranspiration and filtering • Underlying perforated storm sewer or underdrain carries treated storm water to an outlet • Extensive vegetation assists in the filtration of the storm water prior to filtering through the soil Constructed Wetlands • Treat storm water through bio-retention • Designed in a similar manner as a retention basin • Depressed, heavily planted areas designed to maintain a dry weather flow depth of 0.5 to 2 feet Managing the Environmental & Project Development Process

13. NPDES STORMWATER Stormwater Associated with Construction Activity in the Big Darby Creek Watershed and Olentangy Watershed Watershed Specific Permits includes: • Groundwater Recharge, if applicable • Riparian Setback Mitigation • Temporary Sediment Basin Locations • Ohio EPA review and approval of SWPPP Managing the Environmental & Project Development Process

14. Stormwater Associated with Construction Activity in other specific watersheds: • OEPA has developed TMDL Reports for 50 impaired watersheds • The following watersheds have water quality report recommendations for developing a watershed specific Construction General Permit: • Chagrin River • Little Miami River Managing the Environmental & Project Development Process

15. Construction Activity Stormwater Permits Consequences for ODOT: • Increased project footprint • Additional assessment and documentation: • Wider ditches, stormwater ponds & wetlands • Structural additions, manufactured systems… • Increased mitigation: • Stream restoration • Environmental covenants • On going Research Managing the Environmental & Project Development Process

16. Questions? Becky Humphreys (614)387-1125 Stormwater Program Manager Becky.Humphreys@dot.state.oh.us Managing the Environmental & Project Development Process