A study of mixing, water quality and ice cover formation in stormwater ponds

在城市地区，不透水表面的存在导致地表径流的体积和速率大大增加。雨水管理湖，或雨水池，主要是通过暂时储存地表径流，然后以减慢的速度释放，来控制过量的水。雨水池的设计不仅可以减少洪水，还可以通过去除污染物来改善水质。池塘通常位于城市的细分区域，它们靠近住宅产生了两个问题。首先，藻类大量繁殖和水生植物过度生长导致水质差，导致附近居民经常抱怨气味和难看的池塘浮渣的存在。其次，居民们发现冰冻的雨水池对滑冰、曲棍球和扫帚球等冬季娱乐活动很有吸引力，但不可预测的冰盖行为使这些活动变得危险。对冰盖安全的担忧以及埃德蒙顿雨水池中令人讨厌的藻类大量繁殖的持续问题是这项研究计划的动机。拟议研究的目的是：

In urban areas the presence of impervious surfaces results in greatly increased volumes and rates of surface runoff. Stormwater management lakes, or stormwater ponds, are used primarily to control the excess water by temporarily storing surface runoff and then releasing it at a decreased rate. Stormwater ponds are designed not only to reduce flooding but also to improve water quality by removing pollutants. Ponds are often located in urban subdivisions and their close proximity to residential dwellings creates two problems. First, poor water quality caused by algae blooms and excessive aquatic plant growth lead to frequent complaints from nearby residents about odours and the presence of unsightly pond scum. Second, residents find frozen stormwater ponds attractive for winter recreational activities such as skating, hockey and broomball but unpredictable ice cover behaviour makes these activities dangerous. Concerns about the safety of ice covers and the ongoing problems with nuisance algae blooms in Edmonton's stormwater ponds are the motivation for this research proposal. The objectives of the proposed research are to: (i.) Identify the causes of poor water quality in stormwater management ponds. (ii.) Evaluate methods to reduce algae growth in stormwater management ponds. (iii.) Identify the causes of ice cover variability in stormwater management ponds. We propose to achieve these objectives by conducting a two year field measurement program and by applying state-of-the-art numerical models to four Edmonton stormwater ponds. The field measurements will be used to determine the factors that control ice cover formation and algae growth. A coupled hydrodynamic-biogeochemical numerical model will be used to determine the causes of excess algae growth and to evaluate remediation methods to improve water quality. A hydrodynamic numerical model that includes a new ice cover algorithm will be used to predict ice cover formation and to determine the factors that cause pond ice covers to be unsafe.