Effect of morphologic and hydraulic factors on hysteresis of sediment transport rates in alluvial streams

Abstract

Unsteady flow events, such as those caused by extreme precipitation events or reservoir flushing, can result in hysteresis of sediment transport rates in alluvial streams. Over the past 20 years, several experimental studies have been conducted that monitored sediment transport rates in response to unsteady flow event hydrographs. Previous literature has identified numerous morphological and hydraulic factors, including sediment composition, sediment supply, hydrograph characteristics, bed morphology, and mode of sediment transport, that affect hysteresis of sediment transport rates. This manuscript reviews and evaluates the degree of influence of these factors on hysteresis in order to develop a comprehensive understanding of the dominant factors responsible for this phenomenon. This systematic evaluation suggests that the mode of sediment transport and sediment composition are the most dominant factors influencing the resulting type of hysteresis. Further research is required to investigate the effect of other factors, such as non-uniform stream bed composition and planform geometry, and develop predictive models to assess the sediment transport response to unsteady flow events.

Bed Load Sediment Transport and Morphological Evolution in a Degrading Uniform Sediment Channel Under Unsteady Flow Hydrographs

“…It is well recognized that five common classes of hysteresis loop exist for bed load sediment transport under unsteady hydrograph flows, defined as follows: (i) single‐valued , (ii) CW , (iii) CCW, (iv) single‐valued plus a loop , and (v) figure‐8 (e.g., Waters & Curran, ; Williams, ). A recent review of the different morphological and hydraulic factors affecting hysteresis patterns in sediment transport by Gunsolus and Binns () also indicates that the sediment transport mode, bed composition, sediment supply, hydrograph characteristics, and bed morphology all have prominent roles in the type of hysteresis observed. In the current study, the hysteresis patterns for uniform sediment transport under all hydrographs tested are grouped into the three general classifications of CW (i.e., (ii)), CCW (i.e., (iii)), and mixed/no hysteresis (M/N; i.e., (i), (iv), and (v); see Figure and S3).…”

“…It is well recognized that five common classes of hysteresis loop exist for bed load sediment transport under unsteady hydrograph flows, defined as follows: (i) single-valued, (ii) CW, (iii) CCW, (iv) single-valued plus a loop, and (v) figure-8 (e.g., Waters & Curran, 2015;Williams, 1989). A recent review of the different morphological and hydraulic factors affecting hysteresis patterns in sediment transport by Gunsolus and Binns (2017) also indicates that the sediment transport mode, bed composition, sediment supply, hydrograph…”

The impact of hydrograph variability and frequency on sediment transport dynamics in a gravel‐bed flume

“…These experiments illustrate the importance of unsteady hydrograph parameters (shape, flashiness, duration and frequency) on sediment transport and the resulting bed morphology, yet the exact influence of hydrograph characteristics on sediment transport and bed morphology remains largely unknown, as recent studies point out (Gunsolus and Binns, ; Phillips et al, ). Moreover, little work has been done to date that combines changes in hydrograph shape and frequency to investigate sediment transport dynamics.…”

“…Unsteady flow and associated bedload are known to produce hysteresis, i.e. a lag between discharge and bedload transport rates (Gunsolus and Binns, 2017). The mechanistic interpretation of this phenomenon is the modulation of the sediment yields due to the fluctuation of the hydraulic forces exerted on the riverbed (Gunsolus and Binns, 2017) and due to the origin of sediments (proximal or distal availability of sediments) (Juez et al, 2018;Matos et al, 2018).…”

Impact of Unsteady Flow Events on Bedload Transport: A Review of Laboratory Experiments

“…Laboratory research on sediment transport in unsteady flow has been summarized to some extent in a few review papers. They focused on sediment transport characteristics in relation to pollutant transport in unsteady flow [10], factors affecting the hysteretic relationship between flow rate and sediment transport [22], and presented current laboratory techniques applied in bedload studies, both in steady and unsteady flow conditions, and dedicated a few sections to the impact of sediment supply, armoring, and hydrograph on bedload transport in unsteady flow [15].…”