Bioretention application for stormwater management in cold climate

城市化改变了自然水文循环，将具有吸水性的绿地变成混凝土坚硬的表面，导致雨水径流增加，水质恶化。作为补救措施，低影响发展（LID）概念已被引入雨水管理。LID是一种基于生态系统的方法，通过复制自然水文和过程来管理靠近源头的雨水，并恢复土壤和植被的生物降解过程，从而管理雨水。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实践。在温暖和温带气候下，生物滞留系统在减少暴雨水量和峰值流量以及改善暴雨水质方面表现出有效的效果。然而，生物滞留系统在埃德蒙顿和加拿大北部草原等寒冷半干旱气候下的适用性尚未得到研究。本项目的目标是：(1)调查和确定生物滞留系统在当地的土壤修复方案；(2)研究寒冷气候下生物滞留系统对暴雨水量和峰值流量的减少和质量的改善；(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运输机制；(5)评估生物滞留系统处理融雪径流的适用性。本项目将采用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，并为更好地设计寒冷气候下的生物滞留系统提供标准。从事该项目的研究生将接受高质量的培训，并获得在寒冷气候下实施生物滞留系统的宝贵经验，从而更容易就业。

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.