Measurement of Longshore Sediment Transport Rates in the Surf Zone on Galveston Island, Texas

2008 ◽  
Vol 2 ◽  
pp. 62-73 ◽  
Author(s):  
Alison L. Rogers ◽  
Thomas M. Ravens
2017 ◽  
Vol 21 (1) ◽  
pp. 1-13 ◽  
Author(s):  
V. Sanil Kumar ◽  
P. R. Shanas ◽  
G. Udhaba Dora ◽  
Johnson Glejin ◽  
Sajiv Philip

1986 ◽  
Vol 1 (20) ◽  
pp. 135 ◽  
Author(s):  
R.G. Dean

An attempt is made to conduct a rational assessment of the potential adverse effects of coastal armoring on adjacent shorelines and to propose methodology for mitigation, where appropriate. Specific attention is directed toward claims that armoring causes: profile steepening, increased longshore sediment transport, intensified local scour, transport of sand to substantial offshore distances, etc. The assessment presented here is based on a combination of sound principles and the availability or lack, of laboratory and field data to either support or refute the claims. Although it is found that data relating to coastal armoring effects are sparse, conclusions can be drawn. There seems to be no factual data to support the contentions that armoring causes profile steepening, increased longshore transport, transport of sand to a substantial distance offshore, or significantly delayed profile recovery following a severe erosion event. Armoring does have the potential to cause intensified local scour both in front of and at the ends of an armored segment. Reasons for these effects, based on knowledge of response of a natural profile, are presented. Additionally, armoring which projects into the active surf zone can act as a partial barrier to the net longshore sediment transport, thereby causing downdrift erosion. Methodology is presented for quantifying the appropriate mitigation for a particular armoring situation. The proposed mitigation is the annual placement of sand in the vicinity of the armoring to offset its potential adverse effects. The two potential adverse effects addressed in the methodology include the reduction of sediment supplied to the system as a result of the armoring and the blockage of longshore sediment transport by a protruding armoring installation.


1978 ◽  
Vol 1 (16) ◽  
pp. 95 ◽  
Author(s):  
Toru Swaragi ◽  
Ichiro Deguchi

The distributions of longshore and on-offshore sediment transport rates in a surf zone were measured by an apparatus which was able to separately record both components of the sediment transport rate,, The characteristics of their distributions were discussed from the bottom shear stresses which were measured by the shear meter under the same wave conditions as the laboratory experiment of the sediment transport. The maximum bottom shear stress took place at the depth between the breaking depth of waves and the depth where the velocity of the longshore current showed a maximum. On the other hand, the maximum on-offshore and longshore sediment transport rates occured at the depth slightly shallower than the depth where the maximum bottom shear stress took place. What's more, the longshore sediment transport rates were represented by the longshore current velocity and the bottom shear stress generated by waves and the longshore current. However, the distribution of the on-offshore sediment transport rates showed more complicated profile than that of the longshore sediment transport rates because there were no eminent unidirectional flow in the direction normal to the shore line. Therefore, the on-offshore sediment transport rates could not be formulated by the bottom shear stresses.


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.


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.


1978 ◽  
Vol 1 (16) ◽  
pp. 93 ◽  
Author(s):  
Matthew N. Gree ◽  
Ole Secher Madsen

Siltation rates anticipated at harbor entrances, in navigation channels and at inlet structures as well as possible adverse effects caused by these and other coastal engineering constructions are often assessed based on considerations of longshore sediment transport rates. The ability to predict the longshore sediment transport rate is consequently of considerable importance in many coastal engineering problems. The engineering need for an ability to predict longshore sediment transport rates is evidenced by the fact that the development of empirical relationships preceeded, by decades, any attempts at rigorous analyses of the mechanics of sediment transport processes in the surf zone. A predictive relationship for longshore sediment transport rates, which enjoys considerable popularity in the United States, is the empirical relationship suggested by the U.S. Army (1973), Coastal Engineering Research Center (CERC) in their Shore Protection Manual (SPM-73).


1988 ◽  
Vol 1 (21) ◽  
pp. 103
Author(s):  
A.S. Arcilla ◽  
A. Vidaor ◽  
J. Pous

In this paper an improved bulk formulation for the longshore sediment transport rate is presented. It is based on a simplified hydrodynamic analysis of surf zone flow and supplemented by an exhaustive dimensional analysis. The proposed model includes the effect of the surf zone dynamic state (e.g. variation of longshore sand transport, II, with breaker type) and it is now being used in the one- and twoline shoreline evolution models developed by the Maritime Engineering Laboratory in Barcelona.


1995 ◽  
Vol 32 (2) ◽  
pp. 77-83
Author(s):  
Y. Yüksel ◽  
D. Maktav ◽  
S. Kapdasli

Submarine pipelines must be designed to resist wave and current induced hydrodynamic forces especially in and near the surf zone. They are buried as protection against forces in the surf zone, however this procedure is not always feasible particularly on a movable sea bed. For this reason the characteristics of the sediment transport on the construction site of beaches should be investigated. In this investigation, the application of the remote sensing method is introduced in order to determine and observe the coastal morphology, so that submarine pipelines may be protected against undesirable seabed movement.


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

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