Study on the Runoff Generation Mechanism of Green Roofs under Stormwater Scenarios
Green roofs (GRs) are widely employed in urban areas to mitigate the detrimental impacts by stormwater flooding. However, a simple yet physical method for assessing the hydrological performance of GR is still lacking. In this study, we first perform an analysis on the relationship between rainfall depth P and runoff amount R based on the water balance principle and discuss the different runoff generation mechanisms on GR. A field experiment is then conducted to examine the P-R relationship constructed in the previous analysis, which demonstrates good validity in estimating runoff generated on our GR. Numeric simulations via HYDRUS-1D are then carried out to investigate the runoff generation mechanism on GR as well as to examine the applicability of the proposed assessment method. The simulation results indicate that both the saturation and infiltration excess processes occurred on our GR; nonetheless, the infiltration-excess runoff accounts for only a small portion of the total runoff. This implies that the proposed linear model is applicable for estimating the runoff from GR even under heavy rainfall condition where the infiltration-excess mecha- nism is supposedly active.
文章引用: 孙 挺 , 杨文宇 , 倪广恒 (2014) 暴雨条件下绿化屋顶产流机制研究。 水资源研究， 3， 20-28. doi: 10.12677/JWRR.2014.31004
 ZHANG, D.-L., LIN, Y., ZHAO, P., et al. The Beijing extreme rainfall of 21 July 2012: “Right results” but for wrong reasons. Geophysical Research Letters, 2013, 40(7): 1426-1431.
 MENTENS, J., RAES, D. and HERMY, M. Green roofs as a tool for solving the rainwater runoff problem in the urbanized 21st century? Landscape and Urban Planning, 2006, 77(3): 217226.
 TILLINGHAST, E., HUNT, W., JENNINGS, G., et al. Increasing stream geomorphic stability using storm water control measures in a densely urbanized watershed. Journal of Hydrologic Engineering, American Society of Civil Engineers, 2013, 17(12): 1381-1388.
 CARSON, T. B., MARASCO, D. E., CULLIGAN, P. J., et al. Hydrological performance of extensive green roofs in New York City: Observations and multi-year modeling of three full-scale systems. Environmental Research Letters, 2013, 8(2), Article ID: 024036.
 CARTER, T. and RASMUSSEN, T. C. Hydrologic behavior of vegetated roofs. JAWRA Journal of the American Water Resources Association, Blackwell Publishing Ltd, 2006, 42(5): 1261-1274.
 DENARDO, J., JARRETT, A., MANBECK, H., et al. Stormwater mitigation and surface temperature reduction by green roofs. 2005, 48(4): 1491-1496.
 FASSMAN-BECK, E., VOYDE, E., SIMCOCK, R., et al. 4 living roofs in 3 locations: Does configuration affect runoff mitigation? Journal of Hydrology, 2013, 490: 11-20.
 FIORETTI, R., PALLA, A., LANZA, L. G., et al. Green roof energy and water related performance in the Mediterranean climate. Building and Environment, 2010, 45(8): 1890-1904.
 PALLA, A., GNECCO, I. and LANZA, L. G. Compared performance of a conceptual and a mechanistic hydrologic models of a green roof. Hydrological Processes, 2012, 26(1): 73-84.
 STOVIN, V., VESUVIANO, G. and KASMIN, H. The hydrological performance of a green roof test bed under UK climatic conditions. Journal of Hydrology, 2012, 414-415: 148-161.
 TEEMUSK, A. and MANDER, Ü. Rainwater runoff quantity and quality performance from a greenroof: The effects of shortterm events. Ecological Engineering, 2007, 30(3): 271-277.
 JIM, C. Y. and PENG, L. L. H. Substrate moisture effect on water balance and thermal regime of a tropical extensive green roof. Ecological Engineering, 2012, 47: 9-23.
 GETTER, K. L., ROWE, D. B. and ANDRESEN, J. A. Quantifying the effect of slope on extensive green roof stormwater retention. Ecological Engineering, 2007, 31(4): 225-231.
 MORGAN, S., CELIK, S. and RETZLAFF, W. Green roof stormwater runoff quantity and quality. Journal of Environmental Engineering, American Society of Civil Engineers, 2013, 139(4): 471-478.
 SIMMONS, M. T., GARDINER, B., WINDHAGER, S., et al. Green roofs are not created equal: the hydrologic and thermal performance of six different extensive green roofs and reflective and non-reflective roofs in a sub-tropical climate. Urban Ecosystems, 2008, 11(4): 339-348.
 VANWOERT, N. D., ROWE, D. B., ANDRESEN, J. A., et al. Green roof stormwater retention: Effects of roof surface, slope, and media depth. Journal of Environment Quality, 2005, 34(3): 1036-1044.
 VOLDER, A. and DVORAK, B. Event size, substrate water content and vegetation affect storm water retention efficiency of an un-irrigated extensive green roof system in Central Texas. Sustainable Cities and Society, 2013.
 DIGIOVANNI, K., GAFFIN, S. and MONTALTO, F. Green roof hydrology: Results from a small-scale lysimeter setup (Bronx, NY). American Society of Civil Engineers, 2010.
 DUNNETT, N., NAGASE, A. and HALLAM, A. The dynamics of planted and colonising species on a green roof over six growing seasons 2001-2006: Influence of substrate depth. Urban Ecosystems, 2008, 11(4): 373-384.
 VILLARREAL, E. L. Runoff detention effect of a sedum greenroof. Nordic Hydrology, 2007, 38(1): 99-105.
 CARTER, T. and JACKSON, C. R. Vegetated roofs for stormwater management at multiple spatial scales. Landscape and Urban Planning, 2007, 80(1-2): 84-94.
 HILTEN, R. N., LAWRENCE, T. M. and TOLLNER, E. W. Modeling stormwater runoff from green roofs with HYDRUS1D. Journal of Hydrology, 2008, 358(3-4): 288-293.
 SHE, N. and JOSEPH PANG, P. A deterministic lumped dynamic green roof model. American Society of Civil Engineers, 2008.
 ŠIMŮNEK, J., ŠEJNA, M., SAITO, H., et al. HYDRUS 1D software package for simulating the one-dimensional movement of water, heat, and multiple solutes in variably-saturated media. HYDRUS-1D, Department of Environmental Sciences, University of California Riverside, 2009: 1-332.
 VAN GENUCHTEN, M. T. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Science Society of America Journal, 1980, 44(5): 892-898.