A Physically Based Model of Deposition, Re‐Entrainment, and Transport of Fine Sediment in Gravel‐Bed Rivers. Issue 8 (16th August 2022)

• Record Type: Journal Article
• Authors: Haddadchi, Arman; Rose, Calvin W.
• Is Part Of: Water resources research. Volume 58:Issue 8(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-16
• Subjects: suspended sediment -- deposition -- entrainment -- sediment routing; Hydrology -- Periodicals; 333.91
• DOI: 10.1029/2021WR031782
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: Interpreting the links between transient in‐channel fine sediment storage and the dynamics of suspended sediment transport during flood events helps the understanding of river geomorphology, and also the impacts of fine sediment on water quality and bed habitats of rivers and downstream receiving environments. We present a unique physically based model of suspended sediment transport which is intimately coupled with fine sediment deposition and re‐entrainment processes within the gravel bed. This multi‐size fraction theory provides unique information about the effect of fine sediment size classes due to their dynamics and associated river bed changes in net deposition. The data from a series of flood events from the Oreti River, located in Southland, New Zealand were used to test the ability of this theory to provide a description of the dynamics of the fine sediment size distribution, their concentration, load, and rate of river bed deposition and re‐entrainment. After calibration of the model using the data from one flood event, the model provides good agreement between observed and modeled fine sediment concentration and event load for seven subsequent test events. One of the main applications of this theory in future is for routing suspended sediment concentration and changes on fine sediment deposition down a river network. Plain Language Summary: This study introduce a new theory for determining suspended sediment transport and deposition and re‐entrainment of deposited fine sediments in gravel bed rivers. We tested the theory using data from the Oreti River and found good agreements between observed and predicted suspended sediment concentration during flood events and suspended sediment load. Key Points: A new physically based theory of suspended sediment transport with sediment deposition and re‐entrainment rates is presented The theory provides user‐defined size fraction classes integrating at each time step to determine total fine sediment transport The optimization of parameters obtained using the calibration event provide accurate prediction of sediment dynamics for seven test events