scholarly journals STUDY OF RAPID SEDIMENTATION AT PARESAR INTAKE BASIN, CASPIAN SEA, DUE TO LARGE WRACK PARTICLES AND WIND-INDUCED CURRENTS

2020 ◽  
pp. 4
Author(s):  
Mina Rashvand ◽  
Mohsen Soltanpour ◽  
Amir Masoud Moattar Kharrazi
Keyword(s):  
Numerical Modeling ◽  
Sediment Transport ◽  
Water Depth ◽  
Caspian Sea ◽  
Field Measurements ◽  
Longshore Sediment Transport ◽  
Major Increase ◽  
Induced Currents ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

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

scholarly journals Study of Current- and Wave-Induced Sediment Transport in the Nowshahr Port Entrance Channel by Using Numerical Modeling and Field Measurements

2020 ◽  
Vol 8 (4) ◽  
pp. 284 ◽  
Author(s):  
Ayyuob Mahmoodi ◽  
Mir Ahmad Lashteh Neshaei ◽  
Abbas Mansouri ◽  
Mahmood Shafai Bejestan
Keyword(s):  
Numerical Modeling ◽  
Caspian Sea ◽  
Recirculation Zone ◽  
Numerical Models ◽  
Field Measurements ◽  
Sediment Sources ◽  
The Caspian Sea ◽  
Access Channel ◽  
Negative Impacts ◽  
Wave Induced

The Nowshahr port in the southern coastlines of the Caspian Sea is among the oldest northern ports of Iran, first commissioned in the year 1939. In recent years, this port has been faced with severe sedimentation issues in and around its entrance that has had negative impacts on the operability of the port. The present study aims at identifying major reasons for severe sedimentation in the port entrance. First, field measurements were evaluated to gain an in-depth view of the hydrodynamics of the study area. Numerical models then were calibrated and validated against existing field measurements. Results of numerical modeling indicated that wind-induced current is dominant in the Caspian Sea. The numerical results also indicated that in the case of an eastward current direction, the interaction between current and the western breakwater arm would lead to the formation of a separation zone and a recirculation zone to the east of the port entrance region. This eddying circulation could transport suspend settled sediments from eastern shoreline towards the port entrance and its access channel. The results of this paper are mostly based on the study of current patterns around the port in the storm conditions incorporate with the identification of sediment sources.

scholarly journals SUSPENDED SEDIMENT AND LONGSHORE SEDIMENT TRANSPORT DATA REVIEW

1972 ◽  
Vol 1 (13) ◽  
pp. 51 ◽  
Author(s):  
M.M. Das
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Field Measurements ◽  
Field Studies ◽  
Volume Transport ◽  
Transport Rate ◽  
General Validity ◽  
Average Percentage ◽  
Longshore Sediment Transport ◽  
Semi Empirical

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.

scholarly journals AN ENERGETIC TYPE MODEL FOR THE CROSS-SHORE DISTRIBUTION OF TOTAL LONGSHORE SEDIMENT TRANSPORT

2012 ◽  
Vol 1 (33) ◽  
pp. 40 ◽  
Author(s):  
Cüneyt Baykal ◽  
Ayşen Ergin ◽  
Işıkhan Güler
Keyword(s):  
Sediment Transport ◽  
Surf Zone ◽  
Field Measurements ◽  
Sediment Flux ◽  
Type Model ◽  
Main Mode ◽  
Total Load ◽  
Empirical Constant ◽  
Longshore Sediment Transport ◽  
Rate Of Dissipation

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.

scholarly journals Toward a Better Understanding of Sediment Dynamics as a Basis for Maintenance Dredging in Nagan Raya Port, Indonesia

Fluids ◽  
2021 ◽  
Vol 6 (11) ◽  
pp. 397
Author(s):  
Muhammad Zikra ◽  
Shaskya Salsabila ◽  
Kriyo Sambodho
Keyword(s):  
Sediment Transport ◽  
Surf Zone ◽  
Field Measurements ◽  
Wave Direction ◽  
Inlet Channel ◽  
Longshore Sediment Transport ◽  
Modeling Analysis ◽  
Aceh Province ◽  
Maintenance Dredging ◽  
Wave Induced

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.

Field Measurements and Modelling of Longshore Sediment Transport

2007 ◽  
Author(s):  
J. J. Williams ◽  
L. S. Esteves ◽  
M. A. Lisniowski ◽  
H. L. S. Perotto
Keyword(s):  
Sediment Transport ◽  
Field Measurements ◽  
Longshore Sediment Transport
Sign in / Sign up

Export Citation Format

Share Document