ABSTRACT

Rainwater Harvesting System (RWHS) can play a multipurpose role, contributing to the management of rainwater runoff, in addition to the water supply. This article assessed the potential reduction in stormwater runoff by adopting small-scale RWHS in the Brazilian semiarid region based on the Curve-Number (CN). RWHS could minimize runoff in frequency and volume, leading the built environment to perform closer to the land’s natural conditions. Before urbanization, the region had a CN of 76. In post urbanization, a case study of multiple houses showed that the adoption of RWHS could reduce the CN from 86 to 80. A reasonable design (0.5 demand fraction and 2000 L tank capacity) could minimize runoff volume by 34% and frequency of occurrence by 66%. Even RWHS with a minimal design, i.e. small tank capacity and low demand, might contribute to the safety of people, resilience, and sustainability of the city’s infrastructure.

摘要

雨水收集系统（RWHS）可以发挥多种作用，除了供水以外，还有助于雨水径流的管理。本文通过基于曲线数（CN）的巴西半干旱地区采用小型RWHS评估了雨水径流的潜在减少量。RWHS可以最大程度地减少径流量和径流量，从而使建筑环境更接近土地的自然条件。在城市化之前，该区域的CN为76。在城市化之后，对多个房屋进行的案例研究表明，采用RWHS可以将CN从86降低到80。合理的设计（0.5的需求量和2000 L的储罐容量）可以减少径流量34％，减少发生频率66％。即使是最小设计的RWHS，例如小水箱容量和低需求，