A New Framework for Modelling Fine Sediment Transport in Rivers Includes Flocculation to Inform Reservoir Management in Wildfire Impacted Watersheds
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Environmental Studies, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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Environment Canada, Burlington, ON L7R 4A6, Canada
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Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2G7, Canada
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Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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Sustainable Agriculture Sciences Department, Rothamsted Research, North Wyke, Okehampton EX20 2SB, UK
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Ministry of Forests, Lands, Natural Resource Operations and Rural Development, Government of British Columbia, Penticton, BC V2A 7C8, Canada
*
Author to whom correspondence should be addressed.
Academic Editor: Maria Mimikou
Water 2021, 13(17), 2319; https://doi.org/10.3390/w13172319
Received: 31 July 2021 / Revised: 19 August 2021 / Accepted: 20 August 2021 / Published: 24 August 2021
(This article belongs to the Special Issue Modelling of River Flows, Sediment and Contaminants Transport)
Fine-grained cohesive sediment is the primary vector for nutrient and contaminant redistribution through aquatic systems and is a critical indicator of land disturbance. A critical limitation of most existing sediment transport models is that they assume that the transport characteristics of fine sediment can be described using the same approaches that are used for coarse-grained non-cohesive sediment, thereby ignoring the tendency of fine sediment to flocculate. Here, a modelling framework to simulate flow and fine sediment transport in the Crowsnest River, the Castle River, the Oldman River and the Oldman Reservoir after the 2003 Lost Creek wildfire in Alberta, Canada was developed and validated. It is the first to include explicit description of fine sediment deposition/erosion processes as a function of bed shear stress and the flocculation process. This framework integrates four existing numerical models: MOBED, RIVFLOC, RMA2 and RMA4 using river geometry, flow, fine suspended sediment characteristics and bathymetry data. Sediment concentration and particle size distributions computed by RIVFLOC were used as the upstream boundary condition for the reservoir dispersion model RMA4. The predicted particle size distributions and mass of fine river sediment deposited within various sections of the reservoir indicate that most of the fine sediment generated by the upstream disturbance deposits in the reservoir. Deposition patterns of sediment from wildfire-impacted landscapes were different than those from unburned landscapes because of differences in settling behaviour. These differences may lead to zones of relatively increased internal loading of phosphorus to reservoir water columns, thereby increasing the potential for algae proliferation. In light of the growing threats to water resources globally from wildfire, the generic framework described herein can be used to model propagation of fine river sediment and associated nutrients or contaminants to reservoirs under different flow conditions and land use scenarios. The framework is thereby a valuable tool to support decision making for water resources management and catchment planning.
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Keywords:
cohesive sediment; erosion; water supply; turbidity; gravel bed river; ingress; watershed management; source water protection; climate change adaptation; landscape disturbance
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MDPI and ACS Style
Stone, M.; Krishnappan, B.G.; Silins, U.; Emelko, M.B.; Williams, C.H.S.; Collins, A.L.; Spencer, S.A. A New Framework for Modelling Fine Sediment Transport in Rivers Includes Flocculation to Inform Reservoir Management in Wildfire Impacted Watersheds. Water 2021, 13, 2319. https://doi.org/10.3390/w13172319
AMA Style
Stone M, Krishnappan BG, Silins U, Emelko MB, Williams CHS, Collins AL, Spencer SA. A New Framework for Modelling Fine Sediment Transport in Rivers Includes Flocculation to Inform Reservoir Management in Wildfire Impacted Watersheds. Water. 2021; 13(17):2319. https://doi.org/10.3390/w13172319
Chicago/Turabian StyleStone, Micheal, Bommanna G. Krishnappan, Uldis Silins, Monica B. Emelko, Chris H.S. Williams, Adrian L. Collins, and Sheena A. Spencer 2021. "A New Framework for Modelling Fine Sediment Transport in Rivers Includes Flocculation to Inform Reservoir Management in Wildfire Impacted Watersheds" Water 13, no. 17: 2319. https://doi.org/10.3390/w13172319
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