Kashyap Shalini, Dibike Yonas, Shakibaeinia Ahmad, Prowse Terry, Droppo Ian
Environment and Climate Change Canada, Water & Climate Impact Research Centre, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada.
Environment and Climate Change Canada, Canada Centre for Inland Waters, 867 Lakeshore Rd, Burlington, ON, L7S 1A1, Canada.
Environ Sci Pollut Res Int. 2017 Jan;24(3):2286-2303. doi: 10.1007/s11356-016-7931-3. Epub 2016 Nov 3.
Flows and transport of sediment and associated chemical constituents within the lower reaches of the Athabasca River between Fort McMurray and Embarrass Airport are investigated using a two-dimensional (2D) numerical model called Environmental Fluid Dynamics Code (EFDC). The river reach is characterized by complex geometry, including vegetated islands, alternating sand bars and an unpredictable thalweg. The models were setup and validated using available observed data in the region before using them to estimate the levels of cohesive sediment and a select set of chemical constituents, consisting of polycyclic aromatic hydrocarbons (PAHs) and metals, within the river system. Different flow scenarios were considered, and the results show that a large proportion of the cohesive sediment that gets deposited within the study domain originates from the main stem upstream inflow boundary, although Ells River may also contribute substantially during peak flow events. The floodplain, back channels and islands in the river system are found to be the major areas of concern for deposition of sediment and associated chemical constituents. Adsorbed chemical constituents also tend to be greater in the main channel water column, which has higher levels of total suspended sediments, compared to in the flood plain. Moreover, the levels of chemical constituents leaving the river system are found to depend very much on the corresponding river bed concentration levels, resulting in higher outflows with increases in their concentration in the bed sediment.
利用一种名为环境流体动力学代码（EFDC）的二维数值模型，对阿萨巴斯卡河下游麦克默里堡和尴尬机场之间的沉积物及相关化学成分的水流和输运情况进行了研究。该河段具有复杂的几何形状，包括植被岛屿、交替出现的沙洲以及难以预测的深泓线。在使用这些模型估算河流系统内粘性沉积物以及一组选定的化学成分（包括多环芳烃（PAHs）和金属）的含量之前，先利用该地区现有的观测数据对模型进行了设置和验证。考虑了不同的水流情景，结果表明，沉积在研究区域内的大部分粘性沉积物来自上游干流的入流边界，不过在洪峰流量事件期间，埃尔斯河也可能有很大贡献。河流系统中的漫滩、支流和岛屿被发现是沉积物及相关化学成分沉积的主要关注区域。与漫滩相比，主河道水柱中吸附的化学成分往往也更多，主河道水柱中的总悬浮沉积物含量更高。此外，发现离开河流系统的化学成分含量在很大程度上取决于相应的河床浓度水平——河床沉积物中化学成分浓度增加会导致更高的流出量。
