Bioretention for enhancing urban stormwater management

雨水是加拿大水道污染的主要来源，因为它在到达接收水之前，会吸收大量沉积在陆地表面的总悬浮固体、营养物质、有机物、重金属和其他污染物。低影响开发技术(LID)是一种可以改善雨水水质、减少雨水量的现代雨水管理方法。生物保育就是其中一项技术，它涉及到陆地表面的植被洼地。**自90年代S首次使用以来，生物保育得到了广泛的实施，但主要是以临时方式和温和温暖的气候地区，这些地区在加拿大大多数气候带都不典型。去除污染物的基本过程仍然缺乏知识，因此，可预测的生物保留设计所需的实用工具也是如此。为了使工程从业者有信心在加拿大使用这种技术，需要清楚地量化生物保留在管理雨水数量和质量方面的好处，并需要开发设计生物保留的实用工具。拟议的研究项目将把计算机模拟与在不同规模(空间尺度)和两个不同气候带发展的生物保育设施上收集的观测相结合，以回答以下问题：i)控制生物保育中污染物(特别是营养物质)去除的潜在过程是什么？Ii)如何比较和评估不同水文条件(如不同大小的降雨事件)和不同污染物负荷下的生物滞留性能？三)如何利用从不同规模的生物保育设施获得的知识来开发预测工具？Iv)生物保育在加拿大不同的气候条件下表现如何？对这些问题的回答将导致开发可靠的方法来预测生物固位的好处和优化生物固位设计。该项目的结果不仅将提供关于生物固位的有用和明确的技术信息，而且还将为生物固位设计提供实用、有用的工具。**

Stormwater is a major source of pollution in Canadian waterways because it picks up high amounts of total suspended solids, nutrients, organic matter, heavy metals and other pollutants that are deposited on the land surface, before reaching the receiving waters. Low Impact Development technologies (LIDs) are modern stormwater management methods that can improve stormwater quality and reduce stormwater quantity. Bioretention, which involves vegetated depressions in the land surface, is one of these technologies. ** Since its initial use in the 90's, bioretention has seen widespread implementation but primarily in an ad hoc manner and in regions of mild and warm climates, which are atypical of most climate zones in Canada. The knowledge of the underlying processes to remove pollutants is still lacking and hence, so are the practical tools necessary for predictable bioretention design. In order to equip engineering practitioners with the confidence to use such a technology in Canada, the benefits of bioretention in managing stormwater quantity and quality need to be clearly quantified, and the practical tools for designing bioretention need to be developed. The proposed research project will combine computer modelling with observations collected on bioretention facilities developed at different sizes (spatial scales) and in two different climate zones, to answer the following questions: i) What are the underlying processes controlling the removal of pollutants (especially nutrients) in bioretention? ii) How can bioretention performance under different hydrologic conditions (such as different size rain events) and different pollutant loads be compared and evaluated? iii) How can knowledge obtained from bioretention facilities at very different scales be used to develop predictive tools? iv) How does bioretention perform under varying Canadian climate conditions? The answers to these questions will lead to the development of reliable approaches for predicting the benefits of bioretention and optimizing bioretention design. The results from this project will not only provide useful and definitive technical information on bioretention, but the practical, useful tools necessary for bioretention design. **