River Mechanics

Juliën, Pierre Y.

doi:10.1017/9781316107072

Cited by 52 publications

(18 citation statements)

References 174 publications

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“…For this study, the Manning roughness parameter was in the range of a hydraulically smooth channel (0·01 < n < 0·02) (Julien, 2002). In addition, the mean diameter (d 50 ) of the sediment mixture was smaller than the pure sand sediment.…”

Section: Fluvial Erosionmentioning

confidence: 89%

Cantilever failure investigations for cohesive riverbanks

Patsinghasanee¹,

Kimura²,

Shimizu³

et al. 2017

Proceedings of the Institution of Civil Engineers - Water Manag

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Section: Fluvial Erosionmentioning

confidence: 89%

Cantilever failure investigations for cohesive riverbanks

Patsinghasanee¹,

Kimura²,

Shimizu³

et al. 2017

Proceedings of the Institution of Civil Engineers - Water Manag

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“…The river roughness coefficient was calculated with the Manning equation for wide channels due to its large width ( w ) compared to the channel depth ( d ), as w / d ≈ 64. The median of sediment particles within the river bed ( D 50 = 36 mm) is typical of gravels (Julien, 2002). Additionally, the flow data exhibit a considerable difference between the average and bankfull streamflow discharge ( Q bf ≈ 4 Q avg ), hence providing a sufficiently wide range to emphasize the differences in the pertinent HZ characteristics among the different submergence ratios.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Streamflow, Ambient Groundwater, and Sediment Anisotropy on Hyporheic Zone Characteristics in Alternate Bars

Monofy

Boano

2021

Water Resources Research

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The hyporheic zone (HZ) is the area where surface water and groundwater interact in sediments immediately beneath and adjacent to streams, rivers, and riverine estuaries. It possesses unique chemical and biological properties stemming from the mixing between groundwater and surface water (Hester & Gooseff, 2010), and its high potential for nutrients removal and pollutant attenuation has attracted the attention of many researchers (Galloway et al., 2019). The hyporheic flow (Q h) is hydrologically defined as the volume of stream water per unit of time, which flows through the subsurface domain, and it starts and terminates at the stream after a certain period of time (Gooseff, 2010). The hyporheic flux (q h) is the corresponding flow per unit area through the streambed. It differs from groundwater flux by its exchanging back and forth across the sediment-water interface (SWI) at a relatively small scale, typically centimeters to tens of meters; however, groundwater flow travels unidirectionally over much longer distances (Boano et al., 2014). Geomorphic features, including alternate bars, ripples, and meanders, can play a significant role in hyporheic flow characteristics (Herzog et al., 2016). A distinctive feature of alternate bars emerges from the induced 3-D patterns of hyporheic flow due to the hydraulic head variation on its morphology (Tonina & Buffington, 2007, 2009; Trauth et al., 2013). Many studies have been carried out on the HZ characteristics in the 3-D gravel bars morphology. Laboratory experiments and 3-D dimensional modeling were conducted to investigate the effect of streamflow and bar's amplitude variations on hyporheic exchange (Tonina & Buffington, 2007). Besides, the alluvium depth can constrain the HZ extent (Tonina & Buffington, 2011). A predictive model was proposed to estimate the hyporheic residence times (T) dependence on bar submergence, hydraulic conductivity, and the slope of a stream reach (Marzadri et al., 2010). Moreover, the undermining effect of ambient groundwater on HZ was analyzed by Trauth et al. (2013) for fully submerged bars. Despite these many studies, the HZ characteristics in partially submerged bars are not fully understood. The importance of bars with low submergence lies in their common occurrence during low stream flow periods,

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“…Here, U represents the average horizontal component of the velocity in the stream, C is the suspended sediment concentration (mg/L), and E is the eroded or settled sediment balance at each time step. Equations (6), (7), and (8) are solved through a 1-D advection-erosion/settling-diffusion finite difference scheme forward in space and time, where the results are in agreement with a forward time centered space scheme [24,25], as presented in Equation (9), where the courant number is less than 0.5.…”

Section: Shear Stress Erosion-based Formulationmentioning

confidence: 66%

Fine Sediment Modeling During Storm-Based Events in the River Bandon, Ireland

García

Harrington

2019

Water

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The River Bandon located in County Cork (Ireland) has been time-continuously monitored by turbidity probes, as well as automatic and manual suspended sediment sampling. The current work evaluates three different models used to estimate the fine sediment concentration during storm-based events over a period of one year. The modeled suspended sediment concentration is compared with that measured at an event scale. Uncertainty indices are calculated and compared with those presented in the bibliography. An empirically-based model was used as a reference, as this model has been previously applied to evaluate sediment behavior over the same time period in the River Bandon. Three other models have been applied to the gathered data. First is an empirically-based storm events model, based on an exponential function for calculation of the sediment output from the bed. A statistically-based approach first developed for sewers was also evaluated. The third model evaluated was a shear stress erosion-based model based on one parameter. The importance of considering the fine sediment volume stored in the bed and its consolidation to predict the suspended sediment concentration during storm events is clearly evident. Taking into account dry weather periods and the bed erosion in previous events, knowledge on the eroded volume for each storm event is necessary to adjust the parameters for each model. This is achieved by predicting three points of the SSC-time curve: the maximum concentration, C max ; the time to the peak concentration, TPE; and the time from descent from the peak concentration, TDE. From these three points, exponential and logarithmic curves are proposed to represent the complete curve. Other classical models [9,10] are based on shear stress values in the bed, proportional to the bed erosion transported due to the streamflow. These models based on shear stress use an erosion rate, M, with erosion commencing when a critical value of shear stress, τ c , is exceeded. Other authors have previously studied storm events to quantify the fine sediment transport within a reach in a gravel bed river [11,12] through field measurements, considering important aspects such as sediment storage in the mainstream channel and its evolution during inter-event periods. The relationship between suspended sediment concentration, SSC, and fine sediment ingress into gravel bed rivers has been experimentally studied through sediment traps installed in the bed of the stream [13,14]. In general, factors that influence the suspended sediment load during storm events have been extensively studied in recent decades, although much effort is still needed to provide models with the capacity to predict the SSC with low uncertainty indices [5][6][7][8][15][16][17].

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River Mechanics

Cited by 52 publications

References 174 publications

Cantilever failure investigations for cohesive riverbanks

Cantilever failure investigations for cohesive riverbanks

The Effect of Streamflow, Ambient Groundwater, and Sediment Anisotropy on Hyporheic Zone Characteristics in Alternate Bars

Fine Sediment Modeling During Storm-Based Events in the River Bandon, Ireland

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