Stormwater Management University of North Carolina at Chapel Hill Sharon Myers, L.G. Environment, Health, and Safety (919)

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.

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

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

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 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

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

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

Stream Clean Ups

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

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

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

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

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

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.

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

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

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

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

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

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

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