Cross-shore distribution of longshore sediment transport: comparison between predictive formulas and field measurements

2001 ◽  
Vol 44 (2) ◽  
pp. 79-99 ◽  
Author(s):  
Atilla Bayram ◽  
Magnus Larson ◽  
Herman C. Miller ◽  
Nicholas C. Kraus
1972 ◽  
Vol 1 (13) ◽  
pp. 51 ◽  
Author(s):  
M.M. Das

A review of laboratory and field studies on suspended sediment under waves shows that although about five analytical or semi-empirical approaches have been attempted to predict the vertical distribution of suspended sediment, none of the approaches has had its general validity proven. This is mainly due to the lack of knowledge about the characteristics of turbulence of the wave boundary layer and to the lack of a suitable suspended sediment measuring technique for use in waves. Six different suspended sediment measuring techniques have been used in the studies previewed. Although none of them gives completely reliable laboratory or field measurements, an optical system appears to show promise in obtaining information on the mechanics of suspension under waves. The reanalysis of longshore sediment transport data and tests of the relationships Q = A..E , Q = A,,E , and I = A„E , where Q is volume transport rate in cubic yards per day, E is longshore component of wave energy flux in lbs per day per foot of beach and I is immersed weight transport rate in lbs per day, for different subsets of data and using the method of least squares, showed that a single set of A-, A„ and B does not fit all subsets of data with minimum average percentage deviation of observed values from those predictable by the relationships. The subset of data consisting of all but the observations with light weight sediments can be described by the line of fit, Q =1.93 X 10-4E , with the observed data differing from the predicted ones by 74 percent on the average.


2012 ◽  
Vol 1 (33) ◽  
pp. 40 ◽  
Author(s):  
Cüneyt Baykal ◽  
Ayşen Ergin ◽  
Işıkhan Güler

This paper presents an energetic-based simple approach for the computation of cross-shore distribution of total longshore sediment transport (LST) rates. The proposed approach (Baykal 2012) follows similar assumptions with the given formula of Bayram et al. (2007) for the total LST rate (Qlst,t) across the surf zone and is applied to investigate the relation between the rate of dissipation in wave energy flux due to wave breaking and total longshore sediment flux using the available laboratory measurements of Wang et al. (2002) and Gravens and Wang (2007) and the field measurements carried out at Duck site, North Carolina, USA between years 1995-1998 (Miller 1999). The proposed approach is also compared with some of the available distributed total load models. From the comparative studies, it is found that the proposed approach shows good agreement with both the laboratory and field measurements, using a single empirical constant, both qualitatively and quantitatively, especially for the cases where the wave conditions are highly energetic (both for plunging and spilling type breakers) and the suspended load is the main mode of sediment transport in the surf zone.


Author(s):  
Mina Rashvand ◽  
Mohsen Soltanpour ◽  
Amir Masoud Moattar Kharrazi

The rapid sedimentation at the entrance of Paresar intake basin is studied, in which unnatural wrack accumulation at the coast, combined with the existing sand, resulted in a major increase in the actual Longshore Sediment Transport (LST) rate. Considering the volume of updrift fillet at the northwest of main breakwater and the estimated LST rate, the advancement of updrift shoreline was highly unexpected. Sands and vegetative wracks were observed only 3 years after constructing the rubble mound breakwaters, resulting in water depth decrease at the entrance. Employing field measurements and numerical modeling, it is revealed that general wind-induced currents in Caspian Sea, which were ignored in the design, have a small effect on increasing LST rate. The unusual sedimentation can be mainly related to the high percentage of wrack particles at updrift coast.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/UNNnjDHL41k


Fluids ◽  
2021 ◽  
Vol 6 (11) ◽  
pp. 397
Author(s):  
Muhammad Zikra ◽  
Shaskya Salsabila ◽  
Kriyo Sambodho

The Port of 2 × 110 MW Nagan Raya Coal Fired Steam Power Plant is one of the facilities constructed by the State Electricity Company in Aceh Province, Indonesia. During its operation, which began in 2013, the port has dealt with large amounts of sedimentation within the port and ship entrances. The goal of this study is to mitigate the sedimentation problem in the Nagan Raya port by evaluating the effect of maintenance dredging. Field measurements, and hydrodynamic and sediment transport modeling analysis, were conducted during this study. Evaluation of the wind data showed that the dominant wind direction is from south to west. Based on the analysis of the wave data, the dominant wave direction is from the south to the west. Therefore, the wave-induced currents in the surf zone were from south to north. Based on the analysis of longshore sediment transport, the supply of sediments to Nagan Raya port was estimated to be around 40,000–60,000 m3 per year. Results from the sediment model showed that sedimentation of up to 1 m was captured in areas of the inlet channel of Nagan Raya port. The use of a passing system for sand is one of the sedimentation management solutions proposed in this study. The dredged sediment material around the navigation channel was dumped in a dumping area in the middle of the sea at a depth of 11 m, with a distance of 1.5 km from the shoreline. To obtain a greater maximum result, the material disposal distance should be dumped further away, at least at a depth of 20 m or a distance of 20 miles from the coastline.


Author(s):  
J. J. Williams ◽  
L. S. Esteves ◽  
M. A. Lisniowski ◽  
H. L. S. Perotto

1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).


Author(s):  
Naoki AKITA ◽  
Risa KATO ◽  
Hoang Hai DONG ◽  
Tomoaki NAKUMURA ◽  
Norimi MIZUTANI

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2038
Author(s):  
Gennady Gladkov ◽  
Michał Habel ◽  
Zygmunt Babiński ◽  
Pakhom Belyakov

The paper presents recommendations for using the results obtained in sediment transport simulation and modeling of channel deformations in rivers. This work relates to the issues of empirical modeling of the water flow characteristics in natural riverbeds with a movable bottom (alluvial channels) which are extremely complex. The study shows that in the simulation of sediment transport and calculation of channel deformations in the rivers, it is expedient to use the calculation dependences of Chézy’s coefficient for assessing the roughness of the bottom sediment mixture, or the dependences of the form based on the field investigation data. Three models are most commonly used and based on the original formulas of Meyer-Peter and Müller (1948), Einstein (1950) and van Rijn (1984). This work deals with assessing the hydraulic resistance of the channel and improving the river sediment transport model in a simulation of riverbed transformation on the basis of previous research to verify it based on 296 field measurements on the Central-East European lowland rivers. The performed test calculations show that the modified van Rijn formula gives the best results from all the considered variants.


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