Pages 76-91
8、From dredged sediment to supplementary cementitious material: characterization, treatment, and reuse
Mouhamadou Amar, Mahfoud Benzerzour, Joelle Kleib, Nor-Edine Abriak
Pages 92-109
9、Sediment organic matter source estimation and ecological classification in the semi-enclosed Batan Bay Estuary, Philippines
Yuya Ogawa, Yuki Okamoto, Resurreccion Bitoon Sadaba, Mamoru Kanzaki
Pages 110-119
10、Vertical concentration profile of nonuniform sediment
Zhilin Sun, Haolei Zheng, Dan Xu, Chunhong Hu, Chaofan Zhang
Pages 120-126
11、Valorization of harbor dredged sediment activated with blast furnace slag in road layers
Abdelwaheb Ben Slama, Nesma Feki, Daniel Levacher, Moncef Zairi
Pages 127-135
12、Design of sediment detention basins: Scaled model experiments and application
Anita Moldenhauer-Roth, Guillaume Piton, Sebastian Schwindt, Mona Jafarnejad, Anton J. Schleiss
Pages 136-150
13、A 2D well-balanced, coupled model of water flow, sediment transport, and bed evolution based on unstructured grids with efficient variable storage strategy
Zhiyuan Yue, Qingquan Liu, Wei Huang, Peng Hu, Zhixian Cao
Pages 151-160
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1、Numerical investigation of the effect of seasonal variations of depth-of-closure on shoreline evolution
Xuan Tinh Nguyen, Minh Thanh Tran, Hitoshi Tanaka, Trung Viet Nguyen, Yuta Mitobe, Cong Dien Duong
Pages 1-16
https://doi.org/10.1016/j.ijsrc.2020.03.016
https://www.sciencedirect.com/science/article/pii/S100162792030038X
Abstract: The current study presents the effects of seasonal variations in the depth-of-closure (Dc) on shoreline evolution using a numerical, one-line shoreline model. Beach erosion of the southern beach of the Nha Trang Coast, which is located in south central of Vietnam, is selected as the study area. This study area is immensely influenced by the tropical monsoon climate that has a clear pattern of large waves in the northeast monsoon season and calm waves in the non-monsoon season. The analysis of the long-term measured shoreline variations from a video-camera system has found a strong correlation of these variations to the monsoon-dominated wave characteristics in the Nha Trang Bay. Therefore, a new approach for determining the depth-of-closure with consideration of the seasonal wave climate changes is purposed in the current study. By implementing this new approach into a numerical, one-line shoreline model, it is found that the seasonal variations of Dc appear to better describe the periodical shoreline evolution due to the monsoon-dominated wave characteristics for the Nha Trang Coast. Such important findings are considered to commonly apply for monsoon-dominated coastal regions in general. These findings are useful information not only for scientific readers but also for the coastal authorities and managers in order to make better countermeasure plans against this kind of erosion mechanism in the future.
Keywords: Video camera;；Shoreline change; One-line theory; Nha Trang Beach; Depth-of-closure; Monsoon wave climate
2、Experimental assessment and prediction of temporal scour depth around a spur dikeManish Pandey, Manousos Valyrakis, Meilan Qi, Anurag Sharma, Ajay Singh LodhiPages 17-28
https://doi.org/10.1016/j.ijsrc.2020.03.015
https://www.sciencedirect.com/science/article/pii/S1001627920300378
Abstract: Spur dikes are river training structures that have been extensively used worldwide for towards enhancing flood control and the stability of embankments and riverbanks. However, scour around spur dikes can be a major problem affecting their stability and hydraulic performance. The precise computation of temporal scour depth at spur dikes is very important for the design of economical and safe spur dikes. This study focuses on experimentally assessing the temporal variation of scour depth around a vertical wall spur dike and identifying the parameters, which mostly influence spur dike performance for a channel bed surface comprised of sand-gravel mixtures. In the current study, the authors did physical experiments in a flume based study to obtain new data, aimed at deriving a new predictive model for spur dike scour and comparing its performance to others found in the literature. It was found that the dimensionless temporal scour depth variation increases with an increase in (i) the threshold velocity ratio, (ii) the densimetric Froude number of the bed surface sediment mixture, (iii) the flow shallowness (defined as the ratio of the approach flow depth, y, to the spur dike’s transverse length, l), and (iv) the flow depth-particle size ratio. It is also concluded that the temporal scour depth variation in the sediment mixture is influenced by the non-uniformity of sediment and decreases with an increase in the non-uniformity of the sediment mixture. A new mathematical model is derived for the estimation of temporal scour depths in sand-gravel sediment mixtures. The proposed equation has been calibrated and validated with the experimental data, demonstrating a good predictive capacity for the estimation of temporal scour depth evolution.
Keywords: Spur dike; Sand-gravel sediment mixture; Clear-water scour; Time-dependent scour depth
3、Effect of shrub-grass vegetation coverage and slope gradient on runoff and sediment yield under simulated rainfallDandan Han, Jingcheng Deng, Chaojun Gu, Xingmin Mu, .Peng Gao, Jianjian GaoPages 29-37
https://doi.org/10.1016/j.ijsrc.2020.05.004
https://www.sciencedirect.com/science/article/pii/S100162792030055X
Abstract: Evaluating the benefits of sediment and runoff reduction in different vegetation types is essential for studying the mechanisms of soil and water conservation on the Loess Plateau. The experiment was conducted in shrub-grass plots with nine levels of mixed vegetation coverage from 0% to 70%, three slopes (10°,15°, and 20°) and two rainfall intensities (1.0 and 2.5 mm/min). The results showed that the vegetation coverage and slope gradient significantly affect runoff and sediment yield. Shrub-grass vegetation coverage had a significant effect on the runoff start-time, runoff flow velocity, runoff rate, and soil erosion rate on hillslopes. Mixed vegetation coverage could effectively delay the runoff start- time and decrease the runoff flow velocity. However, the effects of the slope gradient on runoff and sediment yield are opposite to those of vegetation coverage. Shrub-grass vegetation coverage could effectively increase runoff and sediment yield reduction benefits, while their benefits were affected by the rainfall intensity. At the 1.0 mm/min rainfall intensity, the reduction in the sediment production rate was greater than that under the 2.5 mm/min intensity. However, when the shrub-grass vegetation coverage exceeded 42%, the runoff reduction benefit was more obvious at higher rainfall intensities. The cumulative sediment yield increased with increasing cumulative runoff, and the rate of increase in the cumulative runoff was greater than that of the cumulative sediment yield with increasing of shrub-grass vegetation coverage. Moreover, there was a power function relationship between cumulative sediment yield and cumulative runoff yield (P < 0.05). Our paper is expected to provide a good reference on the ecological environment and vegetation construction on the Loess Plateau.
Keywords: Simulated rainfall; Shrub-grass coverage; Slope; Runoff and sediment yield
4、Coupled and splitting bedload sediment transport models based on a modified flux-wave approachHossein Mahdizadeh, Soroosh SharifiPages 38-49
https://doi.org/10.1016/j.ijsrc.2020.05.001
https://www.sciencedirect.com/science/article/pii/S1001627920300524
Abstract: Numerical modeling of free-surface flow over a mobile bed with predominantly bedload sediment transport can be done by solving the shallow water and Exner equations using coupled and splitting approaches. The coupled method uses a coupling of the governing equations at the same time step leading to a non-conservative solution. The splitting method solves the Exner and the shallow water equations in a separate manner, and is only capable of modeling weak free-surface and bedload interactions. In the current study, an extended version of a Godunov-type wave propagation algorithm is presented for modeling of morphodynamic systems using both coupled and splitting approaches. In the introduced coupled method the entire morphodynamic system is solved in the form of a conservation law. For the splitting technique, a new wave Riemann decomposition is defined which enables the scheme to be utilized for mild and strong interactions. To consider the bedload sediment discharge within the Exner equation, the Smart and Meyer-Peter & Müller formulae are used. It was found that the coupled solution gives accurate predictions for all investigated flow regimes including propagation over a dry-state using a Courant-Friedrichs-Lewy (CFL) number equal to 0.6. Furthermore, the splitting method was able to model all flow regimes with a lower CFL number of 0.3.Keywords: Bedload sediment transport; Coupled solution; Flux-wave method; Shallow water equations; Splitting technique; Wave propagation algorithm
5、Sensitivity analysis of influencing parameters on slit-type barrier performance against debris flow using 3D-based numerical approachMinseop Kim, Seungrae Lee, Tae-Hyuk Kwon, Shin-Kyu Choi, Jun-Seo JeonPages 50-62
https://doi.org/10.1016/j.ijsrc.2020.04.005
https://www.sciencedirect.com/science/article/pii/S1001627920300512
Abstract: Extreme rainfall-induced debris flow can be catastrophic to an urban area, and installation of slit-type barriers can prevent such damage while minimizing negative impact on environments. However, the performance of slit-type barriers against debris flows remains poorly identified partly due to the innate complexity in interactions between debris flow and solid structure. This paper investigated the flow behaviors of debris affected by slit-type barriers using the computational fluid dynamics (CFD) method, in which the numerical model based on the volume of fluid method was verified using the physical modeling results. The sensitivity analysis was performed by building metamodels to determine the primary parameters influencing the barrier performance against debris flows among various variables, in which the effect of input properties and design parameters, particularly the soil concentration in fluidized debris, initial velocity and volume of debris, the barrier height, and the opening ratio, was evaluated from the perspectives of the flow energy reduction and debris trapping. The initial velocity and volume of debris were found to play a significant role in determining the debris flow characteristics. A decrease in the opening ratio in the channel primarily facilitated the energy reduction and trapping due to the reduced opening size. However, the barrier height exhibited a limited effect when the height was sufficiently high to block the debris flow volume. In addition, it was observed that the double barrier system effectively increased the energy reduction while keeping the benefit of open-type barrier. The developed simulation method and obtained results provide an effective tool and an insight that can contribute to an optimum design of the debris-flow barrier.
Keywords: Debris flow; Slit-type barrier; Numerical simulations; Sensitivity analysis; Mitigation effect
6、Temporal trends of hydro-climatic variables and their relevance in water resource management
Karim Solaimani, Mahmoud Habaibnejad, Abdollah Pirnia
Pages 63-75
https://doi.org/10.1016/j.ijsrc.2020.04.001https://www.sciencedirect.com/science/article/pii/S1001627920300470
Abstract: Identification of temporal changes in hydrological regimes of river basins is an important topic in contemporary hydrology because of the potential impacts of climate change on river flow regimes. For this purpose, long-term historical records of rainfall (P), runoff (Q) and other climatic factors were used to investigate hydrological variability and trends in the Tajan River Basin over the period 1969–1998. Actual evaporation (E), rainfall variability index (d), evaporation ratio (CE) and runoff ratio (CQ) were estimated from the available hydroclimatological records. Mann-Kendall trend analysis and non-parametric Sen's slope estimates were performed on the respective time series variables to detect monotonic trend direction and magnitude of change over time. Rainfall variability index showed that 1973 was the wettest year (δ = +2.039) while 1985 was the driest (δ = -1.584). Also, decades 69–78 and 89–98 were recognized as the wettest and driest decades respectively. The gradient of variation of climatological parameters showed that during the study period, all three parameters of rainfall, evaporation and runoff have decreased and the variations of rainfall and evaporation were significant at the 95% level. Investigation of hydrological changes due of dam construction (1999) showed that the amount and annual distribution of discharge were completely different pre and post-dam construction. Discharge decreased in high water months and increased in low water months to meet water supply demands, especially for agriculture. The relationship between temperature and rainfall trends is compared for three stations in Mazandaran Province (Gorgan, Babolsar and Ramsar) from 1956 to 2003 and nine other stations with different statistical periods of 19–36 years, relating trends to northern hemisphere and global trends. Decreases in temperature were accompanied by decreases in rainfall, and vice versa. These trends were not observed in northern hemisphere and world scales, where temperature increases are accompanied by decreases in rainfall. These variations of hydroclimatological parameters show undesirable water resources situations during the statistical periods if the trend continues severe water resource crises.Keywords: Climate change; Human activity; Hydroclimatological; Trend analysis; Mazandaran; Tajan basin7、Suspended sediment yield modeling in Mahanadi River, India by multi-objective optimization hybridizing artificial intelligence algorithmsArvind Yadav, Snehamoy Chatterjee, Sk Md EqueenuddinPages 76-91https://doi.org/10.1016/j.ijsrc.2020.03.018https://www.sciencedirect.com/science/article/pii/S1001627920300408AbstractRiver sediment produced through weathering is one of the principal landscape modification processes on earth. Rivers are an integral part of the hydrologic cycle and are the major geologic agents that erode the continents and transport water and sediments to the oceans. Estimation of suspended sediment yield is always a key parameter for planning and management of any river system. It is always challenging to model sediment yield using traditional mathematical models because they are incapable of handling the complex non-linearity and non-stationarity. The suspended sediment modeling of the river depends on the number of factors such as rock type, relief, rainfall, temperature, water discharge and catchment area. In this study, we proposed a hybrid genetic algorithm-based multi-objective optimization with artificial neural network (GA-MOO-ANN) with automated parameter tuning model using these factors to estimate the suspended sediment yield in the entire Mahanadi River basin. The model was validated by comparing statistically with other models, and it appeared that the GA-MOO-ANN model has the lowest root mean squared error (0.009) and highest coefficient of correlation (0.885) values among all comparative models (traditional neural network, multiple linear regression, and sediment rating curve) for all stations. It was also observed that the proposed model is the least biased (0.001) model. Thus, the proposed GA-MOO-ANN is the most capable model, compared to other studied models, for estimating the suspended sediment yield in the entire Mahanadi river basin, India. The results also suggested that the proposed GA-MOO-ANN model is unable to estimate suspended sediment yield satisfactorily at gauge stations having very small catchment areas whereas performing satisfactorily on locations having moderate to the large catchment area. The models provide the best result at Tikarapara, the gauge station location in the extreme downstream, having the largest catchment area.
Keywords: Artificial neural network; Genetic algorithm; Multi-objective genetic algorithm; Suspended sediment yield; Mahanadi river
8、From dredged sediment to supplementary cementitious material: characterization, treatment, and reuse
Mouhamadou Amar, Mahfoud Benzerzour, Joelle Kleib, Nor-Edine Abriak
Pages 92-109
https://doi.org/10.1016/j.ijsrc.2020.06.002https://www.sciencedirect.com/science/article/pii/S1001627920300664 AbstractNowadays, the preservation of natural resources, the reuse, and the recycling of waste and by-products in the cement industry are gaining increasing attention in a sustainable development project. In this perspective, many studies focus on finding solutions in order to propose environmentally friendly materials. Nowadays the sediments represent a way to preserve the natural resources by their reuse as a secondary raw material in multiple applications (concrete, roads, landscaped mound, etc.). However, they commonly contain contaminants, organic matter (5%–30%), high water content (50%–200%), and relatively small particle size (Dmax ≤ 300 μm). Therefore to improve the mechanical properties of this material as well as its physiochemical ones, specific methods of characterization and appropriate treatment techniques (calcination, chemical treatment, etc.) are required. This article presents a bibliographical review of the efficient use of sediments in cementitious matrix. It details experimental tests that must be performed to ensure the durability of sediment-based structure and assess their environmental impact under prescribed conditions.
Keywords: Sediment; Characterization; Calcination; Pozzolanicity; Durability
9、Sediment organic matter source estimation and ecological classification in the semi-enclosed Batan Bay Estuary, Philippines
Yuya Ogawa, Yuki Okamoto, Resurreccion Bitoon Sadaba, Mamoru Kanzaki
Pages 110-119
https://doi.org/10.1016/j.ijsrc.2020.05.007
https://www.sciencedirect.com/science/article/pii/S1001627920300585
AbstractL The large organic matter flow in tropical coastal areas is recognized as an important process in the global carbon (C) cycle. However, the nature of organic matter flow in semi-enclosed tropical estuaries remains unclear due to the various environmental processes (tidal change, river flow, waves from the sea, and internal circulation) and organic matter sources therein. Thus, sediment organic matter (SOM) sources, and their distribution pattern, are key to understanding ecosystem material flow. Our research in the Batan Bay Estuary, Philippines, a semi-enclosed estuary under large mangrove deforestation, was conducted to determine ecosystem properties through analysis of C and nitrogen stable isotope ratios and environmental factors. First, we determined that mangrove litter, microphytobenthos, and phytoplankton are the main SOM sources in the Batan Bay Estuary. Second, the estuary was classified into three ecological zones (the Bay zone, Back-barrier zone, and River zone). In addition, we estimated SOM source ratios using the Stable Isotope Analysis in R package and determined different organic matter sources in different zone. The high ratios of mangrove litter as SOM indicate that a large amount of terrestrial plant organic matter remains despite the heavy mangrove deforestation that has occurred since the 1980s, and that the Back-barrier zone consists of a different type of ecosystem that promotes accumulation of C from mangrove litter and microphytobenthos.
Keywords:Mangrove; Sediment organic matter; Stable isotope; Carbon; Nitrogen; SIAR
10、Vertical concentration profile of nonuniform sediment
Zhilin Sun, Haolei Zheng, Dan Xu, Chunhong Hu, Chaofan Zhang
Pages 120-126
https://doi.org/10.1016/j.ijsrc.2020.06.008https://www.sciencedirect.com/science/article/pii/S100162792030072X
Abstract: A new formula for the concentration profile of nonuniform sediment is derived using the diffusion differential equation with equilibrium bed concentration. The interaction coefficient for nonuniform sediment particles as a function of both relative diameter and geometric standard deviation of nonuniform sediment is taken into account in the settling velocity. The diffusion coefficient is obtained from the logarithmic velocity profile. This new formula possesses several advantages as follows: (1) avoids theoretical defect of the Rouse formula, which states that the sediment concentration is infinite at the bottom and zero at the water surface. (2) suitable for an arbitrary fraction of nonuniform sediment, and (3) easy to apply with a simple form. The formula yields less difference among concentration profiles for various particles than that for uniform sediment and reveals the law for fractional concentration distribution of nonuniform sediment. The calculated concentration agrees well with the measured data from the Yangtze River.
Keywords: Nonuniform sediment; Concentration profile; Interaction coefficient
11、Valorization of harbor dredged sediment activated with blast furnace slag in road layers
Abdelwaheb Ben Slama, Nesma Feki, Daniel Levacher, Moncef Zairi
Pages 127-135
https://doi.org/10.1016/j.ijsrc.2020.08.001https://www.sciencedirect.com/science/article/pii/S1001627920300846
Abstract: The valorization solutions for dredged sediment have been the subject of a great number of investigations over the previous decades. In the current present study, treatment of polluted dredged sediment fom the commercial port of Sfax, Tunisia, is proposed. An industrial byproduct (blast furnace slag) was used to bind raw sediment for a reuse in road engineering.Following standards of this field, the raw sediment first was identified and classified according to the French technical guidance. Then an environmental assessment was applied due to the presence of heavy metals. The concentrations were measured on the raw sediment particles so as to control the binding effect on heavy metals. Sediment mixtures consisted of a mix of sand and a blast furnace slag activated with quicklime. Different mixtures were tested and some were proposed for sub-layer applications. The Sfax commercial port raw sediment is considered as a sandy loam with a very low fraction of clay. The measured concentrations of heavy metals exceed the recommended thresholds for cadmium, copper, lead, and zinc. These can induce hazardous effects in the case of their dumping into the sea. On the other hand, the concentrations of the detected elements after leaching tests run on raw sediment samples are very low compared to the thresholds; such results highlight a possible recycling of the raw sediment in subgrade layers without any negative impact. Suitable formulations were deduced for road engineering tests relying on the ratio the California Bearing Ratio index and the immediate bearing index. If the obtained ratio exceeds one, the treated sediment can be recycled and used in road layers.
Keywords: Sediment; Sfax commercial port; Blast furnace slag; Valorization; Road layers; Bearing capacity
12、Design of sediment detention basins: Scaled model experiments and application
Anita Moldenhauer-Roth, Guillaume Piton, Sebastian Schwindt, Mona Jafarnejad, Anton J. Schleiss
Pages 136-150
https://doi.org/10.1016/j.ijsrc.2020.07.007https://www.sciencedirect.com/science/article/pii/S1001627920300792
Abstract: Sediment detention basins are implemented on mountain rivers to trap solid material that may aggravate the flooding of downstream settlements. However, retention structures built in the past may unnecessarily retain sediment during non-hazardous flood events, resulting in high maintenance costs and sediment deficit downstream. In addition, the so-called spontaneous self-flushing of previously retained sediment during floods has occasionally been observed. Recent research suggests to design sediment detention basins for controlling sediment passage with a guiding channel across the deposition area upstream of a hybrid barrier. Such barriers consist of a check dam with a slot orifice and an upstream bar screen with a bottom clearance in order to benefit from a combined mechanical-hydraulic retention control. The present paper enhances this pioneering research with the help of new experimental data, including a wide range of sediment mixtures and large wood, as well as variable barrier heights. Improved design criteria are provided regarding the bar screen and the basin storage capacity. The functionality of the enhanced concept for sediment detention is illustrated by a case study on a physical model: the protection of the Villard-Bonnot village (France) against torrential hazards.Keywords: Sediment continuity; Sediment trap; Bedload; Open check dam; Sediment flushing
13、A 2D well-balanced, coupled model of water flow, sediment transport, and bed evolution based on unstructured grids with efficient variable storage strategy
Zhiyuan Yue, Qingquan Liu, Wei Huang, Peng Hu, Zhixian Cao
Pages 151-160
https://doi.org/10.1016/j.ijsrc.2020.07.005https://www.sciencedirect.com/science/article/pii/S1001627920300779
Abstract: In recent decades, a few Godunov-type, finite volume two-dimensional (2D) unstructured grid, coupled flow, and sediment models (GF2DUCM) have been developed for flows over erodible beds. These kinds of models are generally analyzed as a Vertex Model (VM) that define topography at the cell vertex, which can lead to the non-conservation of mass regarding flow, sediment, and bed evolution. Here, a full cell-cantered variable storage method (Central Model or CM) is applied as the solution of the GF2DUCM. In this method, terrain elevation is defined at the cell centroids; this accurately describes the physical relations between the water depth and topography deformation. This approach can fully eliminate calculation errors in topography deformation at local cells caused by the interpolation of topography deformation at the cell vertex, and reduced uncertainty in the computation of the GF2DUCM. The model performance is systematically tested using a series of laboratory experiments, which demonstrate the mass conservation feature and high accuracy in reproducing hydrodynamic and morphological processes.
Graphical abstract
A well-balanced, two-dimensional (2D) coupled flow–sediment model is established for flows over erodible beds. A Godunov-type, conserved, unstructured grid, finite-volume algorithm with an efficient variable storage strategy is proposed to ensure a strictly conserved system of fluid, sediment, and erodible bed over arbitrary topography. A series of numerical tests demonstrate that the model could successfully simulate dam-break flood processes over fixed and erodible beds.
Keywords: Two-dimensional coupled model; Well-conserved; Unstructured grids; Finite-volume algorithm; Erodible bed; Central model
