ABSTRACT

An increasing interest in retrofitting rooftops as green roofs require improved understanding of the impact on runoff within urban catchments. In this study, a model of Risvollan, an urban catchment in the coastal city of Trondheim, Norway was built using the PCSWMM (Storm Water Management Model) model version 7.2.2780. Rooftops in the catchment were retrofitted as green (vegetated) or grey (non-vegetated – expanded clay, detention-based) roofs. The detention impact was evaluated for nine scenarios using three exceedance thresholds by measuring runoff at the catchment outlet. It was found that implementing green roofs on as little as 11% of the roof area can substantially reduce maximum flows. The implementation of the grey roofs outperformed the green roofs in all the investigated aspects: duration, number, and volume. The study provides insight to urban planners and decision-makers in how to quantify the contribution of rooftop detention to runoff reduction for stormwater management.

摘要

人们越来越需要对屋顶进行改造，因为绿色屋顶需要更好地了解城市集水区对径流的影响。在这项研究中，使用版本7.2.2780的PCSWMM（暴风水管理模型）构建了挪威沿海城市特隆赫姆的城市集水区Risvollan的模型。集水区的屋顶改建为绿色（植被）或灰色（非植被–膨胀粘土，基于滞留的）屋顶。通过测量集水口的径流量，使用三个超限阈值对九种情景的滞留影响进行了评估。人们发现，仅在屋顶面积的11％处安装绿色屋顶可以大大减少最大流量。在研究的所有方面：持续时间，数量和体积方面，灰色屋顶的实施均优于绿色屋顶。