Are the current On-site Stormwater Detention (OSD) policies the best solution for source control stormwater management? A case study of Australian and Brazilian cities

In recent decades On-site Stormwater Detention (OSD) systems have been implemented in many cities around the world. However, a few studies have evaluated the effectiveness of OSD policies. Therefore, this paper compared the use of OSD in Australian and Brazilian cities, evaluating aspects of regulations, technical details and management matters. The results showed that Australian OSD design guidelines are a few steps ahead of Brazilian manuals. However, it is not possible to affirm that the catchment-based approach, adopted by most Australian councils, is better than the site-based approach, embraced by Brazilian cities, since neither is supported by monitoring data of real OSD performance. In general, all municipalities have the same management problems. There is no control over the number of OSDs built in the cities or even the conditions of the systems. Thus, the authors proposed some directions on how OSD policies could be improved.

近数十年来，现场雨水滞留（On-site Stormwater Detention, OSD）系统已在全球诸多城市得到应用。然而，针对OSD政策有效性的评估研究却为数不多。为此，本研究对比了澳大利亚与巴西两国城市的OSD应用情况，从法规规范、技术细节与管理议题三个维度展开评估。研究结果显示，澳大利亚的OSD设计指南相较于巴西的相关手册更为完善。但目前尚无法断言，多数澳大利亚市政当局采用的集水区导向（catchment-based）模式，就优于巴西城市所推行的场地导向（site-based）模式——因为二者均缺乏真实OSD运行性能的监测数据支撑。总体而言，两国市政部门均面临相同的管理困境：既未对城市中已建成的OSD数量进行管控，也未对系统的运行状态实施监管。据此，本文作者提出了若干优化OSD政策的可行方向。