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Stormwater Management University of North Carolina at Chapel Hill

Stormwater Management University of North Carolina at Chapel Hill. Sharon Myers, L.G. Environment, Health, and Safety samyers@email.unc.edu (919) 962-9752. What is Stormwater Runoff?. NC DENR definition:

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Stormwater Management University of North Carolina at Chapel Hill

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  1. Stormwater Management University of North Carolina at Chapel Hill Sharon Myers, L.G. Environment, Health, and Safety samyers@email.unc.edu (919) 962-9752

  2. What is Stormwater Runoff? NC DENR definition: Stormwater runoff is water from rain or melting snow that “runs off” across the land instead of seeping into the ground. This runoff usually flows into the nearest stream, creek, river, lake or ocean. The runoff is not treated in any way.

  3. UNC Stormwater Management Goals • “Balance growth with the preservation of the natural drainage system.” • Meet Town of Chapel Hill Development Plan requirements • Meet NPDES Phase II requirements • Meet TMDL Requirements for Jordan Lake

  4. A Little Background • In 1999 we realized we would be subject to Phase II permitting requirement • Did some research - Duke was paying stormwater fee to Durham of about $230,000 per year • We already were on our way to a good program via master planning process

  5. UNC’s Phase II Application • Submitted application to DENR on March 10, 2003 • Have been through two revision cycles • NC DENR is drafting the permit

  6. 6 Minimum Measures of Phase II • Public Education and Outreach • Public Involvement/Participation • Illicit Discharge Detection and Elimination • Construction Site Stormwater Runoff Control • Post-construction Stormwater Management • Pollution Prevention/Good Housekeeping

  7. Public Outreach and Education • Colleges have a unique population to educate about stormwater issues • Students, employees, and visitors can be reached though university publications, websites, and events • Many UNC employees live outside of Chapel Hill, so town’s outreach program may not be effective

  8. Public Participation • Colleges have many willing volunteers who care about environmental issues • UNC sponsors several stream cleanups every year • Various campus groups participate in drain marking activities

  9. Stream Clean Ups

  10. Illicit Discharge Detection and Elimination • Old buildings have old sanitary sewer pipes • Old buildings have floor drains that connect to the stormwater system • Liquids other than stormwater are disposed to floor drains • Sometimes people dispose of paint, wash water, etc. to the stormwater system • System needs to be completely mapped

  11. Chemetrics Kits • Immediate Results • Ammonia, Detergent, Phenol, Chlorine, Phosphate • Relatively Inexpensive

  12. Construction Site Runoff Control • UNC has erosion and sedimentation control requirements • Emphasis is on covering exposed soils and maintaining ESC measures • Tree protection helps • Construction managers are key • Neighbors help • NC Land Quality Section is our regulatory agency

  13. Post Construction Stormwater Management • Phase II program – mostly addresses water quality • Town of Chapel Hill – addresses rate and volume of runoff in addition to quality

  14. NPDES Phase II Post-Construction Requirements • Control and treat difference between pre and post-development runoff volume for the 1 yr. 24 hr. storm • Volume drawdown in 24 to 120 hrs. • 85% removal for total suspended solids • 30 foot stream buffers • Deed restrictions to protect BMPs • Maintenance program for BMPs

  15. Chapel Hill Development Plan Stormwater Requirements • No increase in the volume of run-off • 2 Year, 24 hour, 3.6” storm event • No increase in peak runoff rates • Remove 85% of suspended solids for the first inch of precipitation • Promise to improve our stormwater practices.

  16. The Problem with Pavement • Increase in pavement or buildings (impervious surface) causes • More water to run off • Water to run off faster • Degraded water quality

  17. Analysis of Best Management Practices (BMPs) • UNC BMP requirements • allow stormwater to infiltrate • allow stormwater reuse • reduce runoff • fit existing landscaping (National Landmark for Outstanding Landscape Architecture by the American Society of Landscape Architects) • allow continued University growth

  18. Infiltration Bed with Reuse • Carmichael Intramural field with storage/infiltration in underlying gravel with water reuse from cistern • Storage:73,500 CF or 550,000 gallons

  19. Riverjacks Open Into Recharge Bed + Pervious Asphalt Stone Bed with 40% Void Space for Storage/Recharge Pervious Pavement

  20. Green Roofs • Carrington Hall Nursing School Addition - offices with a view • Rams Head Center - parking, gym, good food, stormwater

  21. Other BMPs Under Consideration • Rain gardens • Tree trenches • Landscape conversions (lawn to fields, planting areas, reforestation) • Cisterns • Water quality inlets

  22. Pollution Prevention and Good Housekeeping • Secondary containment and covered chemical storage • Thoughtful usage of fertilizers and pesticides • Education for proper disposal of maintenance chemicals and wash waters • Proper disposal or composting of grounds maintenance waste • Street and parking lot sweeping

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