Bioretention application for stormwater management in cold climate

城市化改变了自然的水文循环，将吸水性强的绿色土地变成了混凝土硬地面，导致雨水径流增加，水质恶化。作为一种补救措施，低影响开发（LID）的概念已被引入雨水管理。LID是一种基于生态系统的雨水管理方法，通过复制自然水文和过程来管理靠近其源头的雨水，并恢复土壤和植被中的生物降解过程。生物滞留系统正在成为管理城市雨水数量和质量的最佳管理做法。在暖温带气候条件下，生物滞留系统可有效减少暴雨水量和峰值流量，改善暴雨水质。但是，生物滞留系统在寒冷和半干旱气候中的适用性，如埃德蒙顿和加拿大北方草原，还没有研究。该项目的目标是：（1）调查和确定生物滞留系统的当地土壤改良剂选择，（2）检查寒冷气候下生物滞留系统减少暴雨水量和峰值流量以及改善水质的情况，（3）评估生物滞留系统的长期性能，（4）了解系统中主要污染物的污染物减少和迁移机制，（5）评价生物滞留系统处理融雪径流的适用性。该项目将采取系统的方法进行实验室和实地实验，以实现这些目标。该项目的成果将填补有关寒冷气候下生物滞留系统性能的知识空白，并为寒冷气候下生物滞留系统的更好设计提供标准。从事该项目的研究生将接受高质量的培训，并获得在寒冷气候中实施生物滞留系统的宝贵经验，因此，变得更加就业。

Urbanization has altered the natural hydrologic cycle by turning the absorbent green lands into concrete hard surfaces and resulted in increased storm water runoff and deteriorated water quality. As a remedy, Low Impact Development (LID) concept has been introduced to storm water management. LID is an ecosystem-based approach to manage storm water by replicating natural hydrology and processes to manage storm water close to its source and to restore the biodegradation processes in soils and vegetation. Bioretention systems are becoming best management practices for managing urban storm water quantity and quality. Bioretention systems are shown effective in reducing storm water volume and peak flow and improving storm water quality in warm and temperate climate. However, the applicability of bioretention system in cold and semi-arid climate, such as Edmonton and Canadian Northern Prairies, has not been studied. The objectives of this project are: (1) to investigate and determine local soil amendments options for bioretention systems, (2) to examine storm water volume and peak flow reduction and quality improvements by bioretention systems in cold climate, (3) to evaluate long-term performance of bioretention systems, (4) to understand the pollutant reduction and transport mechanism of major pollutants in the system, and (5) to assess applicability of bioretention system to treat snowmelt runoff. This project will take a systematic approach to conduct laboratory and field experiments to achieve these objectives. The outcome of the project will fill knowledge gaps regarding performance of bioretention systems in cold climate and provide criteria for better design of bioretention systems in cold climate. The graduate students working on this project will receive high quality training and gain valuable experience on implementation of bioretention systems in cold climate, therefore, becoming more employable.