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Using Native Plant Communities as a Template for Green Roof Design . Doug Daley, P.E. Environmental Resources Engineering SUNY College of Environmental Science and Forestry Syracuse, NY Annual Meeting of the American Ecological Engineering Society June7-9, 2012. Summary.
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Using Native Plant Communities as a Template for Green Roof Design Doug Daley, P.E. Environmental Resources Engineering SUNY College of Environmental Science and Forestry Syracuse, NY Annual Meeting of the American Ecological Engineering Society June7-9, 2012
Summary • Native plant communities are used as the basis for a Proof-of-Concept design approach • Rooftop growing conditions at SUNY ESF Gateway Building will emulate dune and alvar communities found along the eastern shore of Lake Ontario • Rooftop system will meet hydrologic performance requirements, support efforts to conserve unique ecological resources, and educate ESF’s broad community, including parents, students, Board, SUNY, municipal officials, designers,…
Green Roof Design in NY • NYS Stormwater Management Design Manual: Green Roof (Chapters 4/5) • Runoff reduction by storage and ET
Design Components - Functional • Structural support • Waterproof barrier • Drainage layer (soil) supports vegetation, no clay, porosity > 15% • Geosynthetic filter fabrics to prevent clogging • Plants with tolerance for regional climate, harsh rooftop conditions and shallow rooting depth (e.g. alpine, arid)
Role of Vegetation • Evapotranspiration • Vegetation on extensive roof captures about 10% of storm event (Michigan State, VanWoert, et al, 2005, JEQ, 34(3): 1036-1044) • Medium captures about 50% • Other values • Aesthetic • Habitat • Conservation
Green Roof Classes • Intensive • Wide variety of plant species, including shrubs and trees, greater diversity of choice • Deeper substrate >4” to 6” • Park-like and accessible • Extensive • Shallow soil (<=4”) • Herbs, mosses, grasses, sedums (NYSDEC) • “Low” maintenance – 2 visits/year to remove “invasives” • Native vegetation is recommended (NYSDEC)
Great Lakes Sand Dunes • Growing conditions include extreme temperatures, strong winds, shifting sands American beachgrass, Ammophilabreviligulata http://www.seagrant.sunysb.edu/glhabitat/PDFS/ELODWAFactSheetDunePlants.pdf
Endangered plant species found there: • Champlain beachgrass (Ammophilabreviligulata), • rough avens (Geumlaciniatum), • woodland bluegrass (Poasylvestris), • marsh horsetail (Equisetum palustre), • large twayblade (Liparisliliifolia), • livid sedge (Carexlivida), • giant pine drops (Pterosporaandromedea) • sand dune willow (Salix cordata).
Alvar Barrens • Prairie-like barrens • Flat, thin- to no-soiled, rocky (limestone bedrock) • Grasslands, limestone woodlands, cedar forests, pavement barrens • Adapted to extreme conditions: • Shallow soil, regular spring flooding, summer drought • Local Nature Conservancy efforts at Chaumont Barrens Preserve, Jefferson County • Extend through Michigan http://www.epa.gov/ecopage/shore/lakeont.html
Plenty of Options for Color and Texture Selected Alvar Species Agropyrontrachycaulum – slender wheatgrass Aquilegia canadensis – wild columbine Artemisacampestrisvar.caudata– tall wormwood Asterciliolatus– aster Bromuskalmii – brome grass Carexeburnea– ebony sedge Carexgranularis– sedge Carexvulpinoidea– brown fox sedge Danthoniaspicata – poverty grass Deschampsiacespitosa – tufted hairgrass Fragariavirginiana –wild strawberry Geumtriflorum – prairie smoke Juniperuscommunis – common juniper Muhlenbergiaglomerata – spike or marshmuhly Oligoneuron album – upland white aster Penstemonhirsutus - hairy beardtongue Rosa blanda – meadow rose Saxifragavirginiensis – early saxifrage Solidagohispida – goldenrod Solidagonemoralis– gray goldenrod Sporobolusheterolepis – northern prairie dropseed Zigadenuselegansvar.glaucus– white camas Ziziaaurea– golden alexanders
Green PRoof • Original design – SUNY CF • Thin soil, sedums • Uprising • Original thought? • Creative design? • World-class environmental science and design programs? • Team of ecologists, LA, engineer
Green PRoof of Concept – Day 13 8” Bed 3” Bed
Tall wormwood, Artemisacampestris var. caudata(Day 10-134) Rapid coverage, great survival
Sand cherry, Prunuspumilavar. depressa Sand cherry was pruned to reduce competition, and provided great color and cover
MiraDrain G4 Drainage Composite • Filter fabric • Moisture retention mat • Drainage mat • Protection Fabric • Storage Capacity = 0.32” rain (7.97 L/m2 )(1.63 lb water/SF) • Flow rate = 75 gpm/SF
Green Roof Runoff Reduction • Water Quality volume (WQv) = 678 CF • Storage Volume= 739 + 0 + 132 + 0 = 871 cf • WQv<Storage P (in) = 90% Rainfall Event Number (See Figure 4.1) = 0.9 I = Impervious Cover = 100 Percent Rv = 0.95 A = site area = 9500 SF Minimum Rv = 0.2 if WQv > RRv
Dune and Alvar Plantings Sand Dune Willow Salix cordata American Beachgrass Wavy Hairgrass Canada Wild Rye Field Wormwood Eastern Sand Cherry
Monitoring • Soil temperature, moisture content • Survival, growth and cover • Pioneers • Precipitation, runoff
Design and Management Issues • Designer resistance • Innovative? Need proof of concept • Faith? • Plant propagation • Sedums are widely available • Cost • Additional soil, unusual plants and increased structural loads • Management • is it a garden, or a native system?
Summary • Native plant communities are used as the basis for a Proof-of-Concept design approach • Rooftop growing conditions at SUNY ESF Gateway Building will emulate dune and alvar communities found along the eastern shore of Lake Ontario • Rooftop system will meet hydrologic performance requirements, support efforts to conserve unique ecological resources, and educate ESF’s broad community, including parents, students, Board, SUNY, municipal officials, designers,…
Acknowledgments • Co-Authors/Investigators/Photographers (SUNY ESF) • Tim Toland • Don Leopold • Terry Ettinger • James Johnson • SUNY Construction Fund • NY Economic Development • Illustrations: Sea Grant New York