Influence of Climatic Factors on Stormwater Runoff Reduction of Green Roofs
North Temperate Zone Greenskins Lab
Runoff Retention / Precipitation (Annual %) Vancouver, BC 29% Malmö, Sweden 47 % Rock Springs, PA 50% Goldsboro, NC 62% Kinston, NC 63% Genova, Italy 51.5 % Washington D.C. 74% Berlin, Germany 75%
Water Balance of Green Roof
Quantify Green Roof Runoff GR Runoff = I + P - ET ± ΔSW GR runoff: green roof runoff I: irrigation P: precipitation ET: evapotranspiration ΔSW: change in soil water content Greenskins Lab
SCS-CN Method Q: runoff P: rainfall CN: curve number Greenskins Lab
Crop Coefficient Method ETc = Kc x ETo ETc: ETo: Kc: evapotranspiration or water use pan evaporation or reference ET crop coefficient Hargreaves- Samani Method Tmean : Tmax : Tmin: Ra: mean daily air temperature daily maximum temperature daily minimum temperature extraterrestrial radiation. Greenskins Lab
Soil: Plant: Rainfall: Temperature: Type, Depth High water use / low water use Amount, Duration, Intensity, Antecedent dry period Monthly mean temperature
Sand (High Porosity ) Soil depth Field capacity Plant available water Loam (Medium Porosity ) Clay (Low Porosity ) Greenskins Lab
Extensive Green Roofs Soil depth: 150mm Available water: 5 18% 7.5 27mm
Rainfall Amount
Rainfall Amount Runoff Retention Low Runoff Reduction Vancouver, BC Washington D.C. Goldsboro, NC Genova, Italy Kinston, NC Malmö, Sweden
Rainfall Amount Runoff Retention Low Runoff Reduction Over 100mm Rainfall Vancouver, BC Washington D.C. Goldsboro, NC Genova, Italy Kinston, NC Malmö, Sweden
Monthly precipitation: below 100mm Runoff Reduction Events 0-25% 26-50% 51-75% 76%-100% Vancouver, BC 13(24) 0 2 1 10 Events happened during the months where total rainfall was below 100mm Rainfall events with detailed measurement
Monthly precipitation: below 100mm Runoff Reduction Events 0-25% 26-50% 51-75% 76%-100% Vancouver, BC 13(24) 0 2 1 10 Rock Springs, PA 11(16) 0 1 1 9 Goldsboro, NC 19(39) 0 1 8 10 Kinston, NC 2(11) 0 0 0 2 Genova, Italy 18(30) 3 2 2 11 Washington D.C. 47(65) 2 1 1 43
Monthly precipitation: over 100mm Runoff Reduction Events 0-25% 26-50% 51-75% 76%-100% Vancouver, BC 11(24) 7 3 1 0 Events happened during the months where total rainfall was over100mm Rainfall events with detailed measurement
Monthly precipitation: above 100mm Runoff Reduction Events 0-25% 26-50% 51-75% 76%-100% Vancouver, BC 11(24) 7 3 1 0 Rock Springs, PA 5(16) 0 3 1 1 Goldsboro, NC 20(39) 2 7 5 6 Kinston, NC 9(11) 2 0 2 5 Genova, Italy 12(30) 10 0 1 1 Washington D.C. 18(65) 1 2 5 10
Monthly Mean Temperature
Rainfall Amount Runoff Retention Low Runoff Reduction Vancouver, BC Washington D.C. Goldsboro, NC Genova, Italy Kinston, NC Malmö, Sweden
Rainfall Amount Runoff Retention Low Runoff Reduction Mean Temperature below 15 C Vancouver, BC Washington D.C. Goldsboro, NC Genova, Italy Kinston, NC Malmö, Sweden
Monthly Mean Temperature : below 15 C Runoff Reduction Events 0-25% 26-50% 51-75% 76%-100% Vancouver, BC 11(24) 7 2 1 0 Events happened during the months where mean temperature was below 15 C Rainfall events with detailed measurement
Monthly Mean Temperature : below 15 C Runoff Reduction Events 0-25% 26-50% 51-75% 76%-100% Vancouver, BC 11(24) 7 2 1 0 Rock Springs, PA 6(16) 1 4 0 1 Goldsboro, NC 7(39) 0 0 3 4 Kinston, NC 4(11) 2 0 0 2 Genova, Italy 14(30) 9 0 2 3 Washington D.C. 44(65) 3 3 3 35 Mostly small rainfall events
Monthly Mean Temperature : above 15 C Runoff Reduction Events 0-25% 26-50% 51-75% 76%-100% Vancouver, BC 13(24) 0 2 1 10 Events happened during the months where mean temperature was above 15 C Rainfall events with detailed measurement
Monthly Mean Temperature : above 15 C Runoff Reduction Events 0-25% 26-50% 51-75% 76%-100% Vancouver, BC 13(24) 0 2 1 10 Rock Springs, PA 10(16) 0 1 1 8 Goldsboro, NC 32(39) 2 8 10 12 Kinston, NC 7(11) 0 0 2 5 Genova, Italy 16(30) 4 2 1 9 Washington D.C. 21(65) 0 0 3 18
Duration, Intensity
Runoff Reduction Events 0-25% 26-50% 51-75% 76%-100% Vancouver, BC 24 7 5 2 10 3.8m 18h 5.6mm 23h Light Rock Springs, PA 3.6mm 2.5h 6.4m 24.75h 2.8mm 3h 9.9m 5.5h 9 1 4 2 2 12.95mm 0.8h 15.24m 0.75h 17.53mm 0.16h 17.27mm 0.16h 36.32m 2.25h 18mm 3.75h 39.4mm 3.25h Heavy 17.02mm 0.16h 24.89m 4.25h
Antecedent Dry Period
Runoff Reduction Events 0-25% 26-50% 51-75% 76%-100% Vancouver, BC 24 7 5 2 10 Rock Springs, PA 9 1 4 2 2 Genova, Italy 0d 1d 1d 28d 11 5 4 1 1 0d 4d Long 5d 7d 2d 13d Long Long Long 0d 7d 0d 1d 4d 0d 1d 2d 4d 9d Short Short
Summary
Rainfall Amount Temperature Duration, Intensity Antecedent Dry Period
Philadelphia Rainfall (2004) Rainfall Amount
Philadelphia Rainfall (2004) Mean Temperature > 15 C
Calculated Runoff Reduction: Philadelphia Intensive green roof Extensive green roof 200mm 0 mm Jan Dec Jan Dec 90% 24%
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