Quinn Ruth, Rougé Charles, Stovin Virginia
Department of Civil and Structural Engineering, The University of Sheffield, UK.
Water Res X. 2020 Dec 13;10:100081. doi: 10.1016/j.wroa.2020.100081. eCollection 2021 Jan 1.
Rainwater harvesting systems in urban settings are increasingly relied upon to mitigate pluvial flooding on top of providing an additional water supply. Alternative designs have been proposed to support their dual use. Stormwater management performance is typically evaluated through long-term averages. However, long-term assessment is not aligned with the goal of attenuating the impacts of short duration high-intensity rainfall events. This paper contributes a framework for evaluating the dual-use performance of design alternatives. The framework incorporates a set of stormwater management metrics that provides a robust characterisation of performance during significant rainfall events. To the usual long-term volumetric retention metric, we add: 1) metrics that represent the total volume and duration above predevelopment (greenfield) runoff rates; and 2) robust peak outflow rate and retention efficiencies based on the long-term median of a representative sample of significant rainfall events. Our multi-criteria performance visualisations of alternative dual-use designs highlight the importance of carefully designing the forecast-based controlled release mechanisms built into active systems. This work has direct implications for design guidance standards, which we discuss.
城市环境中的雨水收集系统越来越多地被用于缓解暴雨洪水，同时还能提供额外的供水。人们提出了替代设计方案来支持其双重用途。雨水管理性能通常通过长期平均值来评估。然而，长期评估与减轻短历时高强度降雨事件影响的目标不一致。本文提出了一个评估设计方案双重用途性能的框架。该框架纳入了一组雨水管理指标，这些指标能在重大降雨事件期间对性能进行有力的表征。除了通常的长期体积保留指标外，我们还增加了：1）代表超过开发前（绿地）径流率的总体积和持续时间的指标；2）基于重大降雨事件代表性样本的长期中位数得出的稳健峰值流出率和保留效率。我们对替代双重用途设计的多标准性能可视化突出了精心设计主动系统中基于预测的控释机制的重要性。这项工作对设计指导标准有直接影响，我们将对此进行讨论。
