Authors: Shalini Kashyap Yonas Dibike Ahmad Shakibaeinia Terry Prowse Ian Droppo
Publish Date: 2016/11/03
Volume: 24, Issue: 3, Pages: 2286-2303
Abstract
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 twodimensional 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 sedimentThe financial support for this study was provided by the Government of Alberta and Environment Canada Joint OilSands Monitoring Program JOSMP The authors would like to thank Drs Fred Wrona and Anil Gupta of Alberta Environmental Monitoring and Science Division as well as Drs Patricia Chambers and Malcolm Conly of Environment and Climate Change Canada for their contributions and constructive suggestions at the various stages of this project The authors acknowledge the help of Ali Oveisy in developing the model grids and Paul Craig from Dynamic Solutions International for his support of the EFDC software The authors would like to thank Dr Fay Hicks for providing some of the lower Athabasca River crosssection data and Dr Roderick Hazewinkel from Alberta Environment and Parks for facilitating access to the LIDAR data used for preparing the bathymetry for the Athabasca River and its flood plains
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