Green Infrastructure at the Campus and Watershed Scale at the University of North Carolina at Chapel Hill Carolyn Elfland, UNC Chapel Hill Sharon Myers, UNC Chapel Hill Ted Brown, Biohabitats, Inc. Sally Hoyt, Biohabitats, Inc.

Carolina North Main Campus Mason Farm

Overview Background Regulatory Framework Central Campus BMP Implementation Lessons Learned Carolina North Opportunities

Background Central Campus 740 acres 13.4 million square feet in million square feet to be added by 2010 Stormwater Issues Flooding and pipe surcharging increasing in frequency and severity Need to improve water quality leaving the campus

Background Satellite Campus – Carolina North 1000 acres Undeveloped except for small general aviation airport Plan to develop 250 acres in 50 years Aggressive sustainability goals, including stormwater

Regulatory Framework Town of Chapel Hill Zoning 85% TSS removal for first 1 inch of preciptation Volume leaving site post-development shall not exceed volume pre-development for the 2 year 24 hour storm event (3.60 inches) Rate leaving site post-development shall not exceed rate pre-development for the 1 year storm – 3.0 inches 2 year – 3.60 inches 25 year – 6.41 inches 50 year – 7.21 inches

Regulatory Framework Jordan Lake TMDL Existing development or redevelopment 35% total nitrogen reduction 5% total phosphorus reduction New development 2.2 lbs/acre/year unit loading rate target for total nitrogen 0.82 lbs/acre/year unit loading rate target for total phosphorus

Watersheds Bolin (lavender) Battle (gray) Chapel (blue) Meeting of the Waters (pink) Morgan (beige)

Campus Best Management Practices Type of BMP Number Green Roofs 3 Permeable Pavement 7 Bioretention9 Vegetated Conveyance 2 Ponds and Wetlands 9 Underground Water Quality Devices 7 Underground Storage (including cisterns) 19 Land Cover Conversions 15

Best Management Practices PhillipsHall/MemorialHall

EstesStorageLot

FridayCenterLot

CarringtonHall

HookerFields

RamsHeadCenter

plastic storage modules cisterns RamsHeadCenter Best Management Practices

RamsHeadCenter

RamsHeadCenter

RamsHeadCenter

Fed-ExGlobalEducation

Land Cover Pre- Construction Change Without BMPs Change With BMPs Pervious Acreage acres acres Impervious Acreage acres acres Total Nitrogen +224 lbs/yr -556 lbs/yr Total Phosphorus +14 lbs/yr -57 lbs/yr

Central Campus Lessons Learned Don’t put cisterns on roofs Cistern water is not free Make careful plant selections for green roofs Porous paving design makes a difference High quality fill material is important Education is critical

Carolina North Carolina North Applying Central Campus Lessons in an Integrated, Sustainable and Holistic Manner

Carolina North Up to 250 acres of a 1,000 acre parcel to be developed sustainably (energy, landscape, water, transportation, buildings) over next 50 years.Up to 250 acres of a 1,000 acre parcel to be developed sustainably (energy, landscape, water, transportation, buildings) over next 50 years. Currently small regional airstrip surrounded by mixed hardwood and pine forest.Currently small regional airstrip surrounded by mixed hardwood and pine forest. Site also contains an inactive municipal landfill, a chemical waste site currently undergoing remediation and old municipal public works and bus depot yardsSite also contains an inactive municipal landfill, a chemical waste site currently undergoing remediation and old municipal public works and bus depot yards

Phase 1 – First 15 Years

Phase 1 Principles Respect the ecology of the site Focus on transit-oriented development Create a sense of identity and place Provide appropriate local connections for bike, pedestrian, transit & roadways Design for efficient land use with appropriate density

Stormwater Strategies Develop a water budget for the site that mimics the natural, undisturbed infiltration capacity of the land using practices and techniques that emphasize vegetative filtering and uptake and/or infiltration.Develop a water budget for the site that mimics the natural, undisturbed infiltration capacity of the land using practices and techniques that emphasize vegetative filtering and uptake and/or infiltration. Provide water quality treatment for all impervious areas using practices that emphasize vegetative filtering and uptake and/or infiltration.Provide water quality treatment for all impervious areas using practices that emphasize vegetative filtering and uptake and/or infiltration. Provide treatment as close to the generating source as possible.Provide treatment as close to the generating source as possible. Horace Williams - Carolina North

Existing Land Cover for Phase 1 at Carolina North

Proposed Land Cover for Phase 1 at Carolina North

Summary of Existing and Proposed Conditions Peak Discharge and Runoff Volume Assumes no water quality or water quantity controls in place.Assumes no water quality or water quantity controls in place.

Summary of Peak Discharge and Runoff Volume with Application of Green Infrastructure Assumes half of impervious surface (~34 acres) is converted to either green roofs or porous pavement.Assumes half of impervious surface (~34 acres) is converted to either green roofs or porous pavement. Still requires ~8 acre-feet of storage to provide peak flow attenuation.Still requires ~8 acre-feet of storage to provide peak flow attenuation.

New Development Nutrient Loading Pre- and Post-development Jordan lake unit loading criteria (2.2 lbs/ac/yr and 0.82 lbs/ac/yr for TN and TP, respectively) are required for 20 acres of new development.Jordan lake unit loading criteria (2.2 lbs/ac/yr and 0.82 lbs/ac/yr for TN and TP, respectively) are required for 20 acres of new development. Computations based on Tar Pamlico unit loading spreadsheet.Computations based on Tar Pamlico unit loading spreadsheet.

Nutrient Export with Application of Green Infrastructure Components Half the rooftops to be green roofs, the other half served by cisterns.Half the rooftops to be green roofs, the other half served by cisterns. Half of the transportation area porous, and half of the managed turf area converted to forest.Half of the transportation area porous, and half of the managed turf area converted to forest. Green roofs behave like managed pervious areas. Area draining to cisterns removed from the total area (total area is reduced from 20 acres to 16.7 acres).Green roofs behave like managed pervious areas. Area draining to cisterns removed from the total area (total area is reduced from 20 acres to 16.7 acres). Area consumed by porous pavement has same loading as managed pervious area.Area consumed by porous pavement has same loading as managed pervious area. BMPs removal as 35% and 45% for total nitrogen and total phosphorus, respectively.BMPs removal as 35% and 45% for total nitrogen and total phosphorus, respectively.

Conclusion UNC has committed to wide-scale implementation of green infrastructure elements across its campus, using an adaptive management approach.UNC has committed to wide-scale implementation of green infrastructure elements across its campus, using an adaptive management approach. Campus is evolving towards a whole systems approach that considers the benefits and treatment capabilities of soils, vegetation, and topography as well as the beneficial uses achieved through rainwater harvesting and water conservation.Campus is evolving towards a whole systems approach that considers the benefits and treatment capabilities of soils, vegetation, and topography as well as the beneficial uses achieved through rainwater harvesting and water conservation. Carolina North will be an example of UNC holistically applying green infrastructure principles in a fully integrated and multi-functional manner.Carolina North will be an example of UNC holistically applying green infrastructure principles in a fully integrated and multi-functional manner. The intended outcome of UNC’s green infrastructure efforts is to maintain the sense of place that defines the campus community by creating and enhancing connections and linkages between human and natural systems in a manner that promotes education, stewardship, and participation.The intended outcome of UNC’s green infrastructure efforts is to maintain the sense of place that defines the campus community by creating and enhancing connections and linkages between human and natural systems in a manner that promotes education, stewardship, and participation.

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