Two-dimensional numerical modelling of sediment and chemical constituent transport within the lower reaches of the Athabasca River.
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.
Environment and Climate Change Canada, Water & Climate Impact Research Centre, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada. shalini.kashyap@gmail.com.
Shalini
http://orcid.org/0000-0002-4365-2557
S
Kashyap
Environment and Climate Change Canada, Water & Climate Impact Research Centre, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada.
Yonas
Y
Dibike
Environment and Climate Change Canada, Water & Climate Impact Research Centre, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada.
Ahmad
A
Shakibaeinia
Environment and Climate Change Canada, Water & Climate Impact Research Centre, 3800 Finnerty Road, Victoria, BC, V8P 5C2, Canada.
Terry
T
Prowse
Environment and Climate Change Canada, Canada Centre for Inland Waters, 867 Lakeshore Rd, Burlington, ON, L7S 1A1, Canada.
Ian
I
Droppo
D004784:Environmental Monitoring / Q000379:methods; D055868:Floods; D019015:Geologic Sediments; D008670:Metals; D008962:Models, Theoretical; D011084:Polycyclic Aromatic Hydrocarbons; D045483:Rivers; D014874:Water Pollutants, Chemical
D008670:Metals; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical
Athabasca River; EFDC; Numerical modelling; River engineering; Sediment transport; Water quality