Impacts of Urbanization on Stormwater Pollutant Loadings and River Water Quality

雨水/融雪径流将积聚在道路和其他城市表面的人为和自然污染物冲入雨水下水道，然后进入受纳水体，对水质和生态系统构成严重威胁。尤其是在加拿大和美国北部的市政当局，冬季使用的大量道路除冰盐/沙子可能会在春季径流到接收水体的过程中产生冲击效应，据报道，氯浓度超过加拿大急性暴露指南的600%。在快速城市化和气候变化的背景下，这种威胁将进一步加剧和复杂化。该计划的长期目标是揭示和量化城市化和气候变化对接收水体的耦合影响，并研究提高城市和河流/湖泊的可持续性和弹性的创新方法，以将此类影响降至最低。在接下来的5年里，我将以埃德蒙顿和北萨斯喀彻温河为例，重点研究城市化对雨水污染物负荷和受纳河流水质的影响。该计划提出了两项研究。目的1研究较少报道的常见但重要污染物(营养物、沉积物、盐分)的暴雨负荷的时空变异性，未报道的城市化水平与负荷的关系，以及春季径流期间负荷对受纳河流的潜在冲击效应。目标2将首次量化城市雨水中一种新出现的污染物(微塑料，MPS)的负载量，并调查未探索的水动力对MP在河流中的运输和去向的影响。对于目标1和目标2中的MP装载，建议在选定的风暴排水口进行现场监测。对于目标2，将进行不同水动力条件和不同MP特性(材料/密度、尺寸和形状)下MP在水槽中的输送和再悬浮的实验室试验。基于粒子图像测速技术、粒子跟踪测速技术和平面激光诱导荧光技术，发展了一种新型的MP速度和浓度测量技术。将对目标1的污染物负荷和河流水质进行数值模拟，并对目标2的MP输送和再悬浮进行数值模拟。提案中列出的所有主要设备/软件都可以在美国大学的水资源组使用。拟议的研究将产生关于城市雨水污染物负荷以及MPS在水中的运输和去向的创新和原创性知识。研究结果还将有助于加拿大三级政府制定/调整关于城市发展和河流/湖泊的最大总污染物负荷以及除冰盐/沙和雨水管理的许多计划/政策。这项研究将在咨询公司、公用事业公司和政府部门非常希望的领域培训7名HQP。

Stormwater/snowmelt runoff flushes anthropogenic and natural pollutants accumulated on roads and other urban surfaces into storm sewers and then into receiving water bodies, posing significant threats to the water quality and ecosystem. This is particularly true for municipalities in Canada and the northern US where the large amounts of road de-icing salts/sands used in winter can potentially have a shock effect during spring runoff to the receiving water bodies, with chloride concentration reported as high as 600% over the Canadian acute exposure guideline. In the context of fast urbanization and climate change, such threats will be further intensified and complicated. The long-term goals of this program are to reveal and quantify the coupled impacts of urbanization and climate change to receiving water bodies and to research innovative ways to enhance the sustainability and resiliency of both cities and rivers/lakes to minimize such impacts. In the next 5 years, I will focus on urbanization impact to stormwater pollutant loadings and receiving river water quality using Edmonton and the North Saskatchewan River as an example. Two studies are proposed in the program. Aim 1 will research the less-reported temporospatial variability of stormwater loadings of common yet important pollutants (nutrients, sediments, salts), the un-reported relation of urbanization level with the loadings, and the overlooked potential shock effect of the loadings to receiving rivers during spring runoff. Aim 2 will quantify, for the first time, the loading of an emerging pollutant (microplastics, MPs) in urban stormwater, and investigate the unexplored hydrodynamic impact to MP transport and fate in rivers. Field monitoring is proposed at selected storm outfalls for Aim 1 and MP loading in Aim 2. Lab experiments will be conducted for Aim 2 on MP transport and re-suspension in a flume under different hydrodynamic conditions and with different MP properties (materials/densities, sizes and shapes). An innovative measurement technique for MP velocity and concentration will be developed based on particle image velocimetry, particle tracking velocimetry and planar laser-induced fluorescence. Numerical modeling will be conducted for pollutant loadings and river water quality in Aim 1, and MP transport and re-suspension in Aim 2. All the major devices/software listed in the proposal are available for use in the Water Resources Group at the UofA. The proposed research will generate innovative, original knowledge on urban stormwater pollutant loadings and transport and fate of MPs in water. The research results will be also useful in Canada's three levels of governments in making/adjusting numerous plans/policies on urban development and maximum total pollutant loadings to rivers/lakes, as well as on de-icing salts/sands and stormwater management. The research will train 7 HQP in areas that are highly desirable by consulting firms, utility companies and government sectors.