scholarly journals A COMPREHENSIVE SEDIMENT BUDGET FOR THE MISSISSIPPI BARRIER ISLANDS

2012 ◽  
Vol 1 (33) ◽  
pp. 81 ◽  
Author(s):  
Dirk-Jan Walstra ◽  
J. De Vroeg ◽  
J. Van Thiel de Vries ◽  
C. Swinkels ◽  
A. Luijendijk ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Transport Model ◽  
Barrier Islands ◽  
Sediment Budget ◽  
Littoral Drift ◽  
Island Restoration ◽  
Mississippi Sound ◽  
Longshore Transport ◽  
Sound Side ◽  
Order Of Magnitude

In order to conceive any realistic plan for post-Katrina island restoration, it is necessary to understand the physical processes that move sand along the littoral drift zone off the coast of Mississippi. This littoral zone influences the character of the Mississippi barrier islands as they exist in an ever changing cycle. To help in this understanding, a sediment transport model was conducted to establish a current sediment budget for the islands. This study evaluated the existing regional sediment transport magnitudes and directions for the Mississippi and Alabama barrier islands fronting Mississippi Sound including daily conditions and hurricanes. A method was developed to incorporate all relevant hurricanes from 1917 to 2010 in the analysis. For the long term average net longshore transport along the southern shorelines of the barriers (i.e. exposed to the Gulf of Mexico), the contribution of year-averaged conditions and hurricanes are of similar order of magnitude, although the mean annual percentage occurrence of hurricanes is no more than about 3%. Along the northern shores (Mississippi Sound side) the transport is considerably smaller and the contributions of cold fronts and hurricanes to the sediment transports are more or less equal. For the year-averaged conditions (excluding hurricanes) a westward directed net transport is found. The net effect of the historic hurricanes is also westward in direction. However, for individual hurricanes (e.g. Camille and Katrina) the net transport along Ship Island can be directed eastward due to the dominance of ebb flows after the eye of the hurricane had passed.

scholarly journals NUMERICAL MODEL INVESTIGATION OF SELECTED TIDAL INLET-BAY SYSTEM CHARACTERISTICS

1978 ◽  
Vol 1 (16) ◽  
pp. 76
Author(s):  
William N. Seelig ◽  
Robert M. Sorensen
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Transport Model ◽  
Tidal Inlet ◽  
Inlet Channel ◽  
Astronomical Tide ◽  
Order Of Magnitude ◽  
Flow And Sediment Transport ◽  
Transport Factors ◽  
System Characteristics

A spatially integrated one-dimensional numerical model of inlet bay hydraulics has been combined with a simple sediment transport model to investigate selected tidal inlet-bay system characteristics. A parametric study has been performed using the models to determine the effect of various factors on the net direction and order of magnitude of inlet channel flow and sediment transport. Factors considered include astronomical tide type, storm surge height and duration, variation in bay surface area, time-dependent channel friction factor, and the addition of a second inlet connecting the bay and sea.

scholarly journals THE IMPACT OF BARRIER ISLAND DEGRADATION ON HURRICANE-INDUCED SEDIMENT TRANSPORT

2018 ◽  
pp. 49
Author(s):  
Ke Liu ◽  
Qin Chen ◽  
Kelin Hu
Keyword(s):  
Sediment Transport ◽  
Storm Surge ◽  
Coastal Wetland ◽  
Transport Model ◽  
Three Dimensional ◽  
Barrier Islands ◽  
Coastal Morphology ◽  
Major Barrier ◽  
Barataria Bay ◽  
The Impact

Hurricanes are recognized as a strong forcing in changing coastal morphology by redistributing sediments. Barrier islands protect estuaries from storm surge and severe waves and confine water and sediment discharge into estuaries during a hurricane event. In this study, we developed a three-dimensional, fully coupled storm surge, waves, and sediment transport model. The impacts of barrier islands degradation on hurricane hydrodynamics and sediment dynamics were evaluated by comparing a hypothetical model configuration for four major barrier islands in Terrebonne Bay and Barataria Bay against a baseline configuration. With the hypothetical deterioration of barrier islands, model results showed that the sediment transport from the shelf to the estuary increased in Terrebonne Bay but decreased in Barataria Bay. In the simulations, most of the deposition on coastal wetland still originated from the bay even when the barrier islands were degraded.

Longshore sediment transport and a sediment for the Malpeque barrier system, southern Gulf of St. Lawrence

1977 ◽  
Vol 14 (11) ◽  
pp. 2429-2439 ◽  
Author(s):  
J. W. Armon ◽  
S. B. McCann
Keyword(s):  
Sediment Transport ◽  
Transport System ◽  
Prince Edward Island ◽  
Barrier Island ◽  
Sediment Budget ◽  
Budget Analysis ◽  
Longshore Sediment Transport ◽  
Longshore Transport ◽  
Principal Source ◽  
Wave Hindcasting

Wave hindcasting and refraction techniques were used to establish inshore wave conditions and longshore sediment transport rates along a 43 km barrier island shoreline at Malpeque, Prince Edward Island, in the southern Gulf of St. Lawrence. Net longshore sediment transport is directed southeastwards, at rates varying from 40 000 m3 year−1 to greater than 200 000 m3 year−1. The information on longshore transport was combined with volumetric estimates of shore normal sedimentary exchanges to define the sediment budget of the barrier sands at Malpeque. The results of the budget analysis indicate that subtidal erosion in the shoreface zone is the principal source of sand for the longshore transport system.

Sandy sediment budget of the midcoast of Rio Grande do Sul, Brazil

2015 ◽  
Vol 73 (3) ◽  
pp. 49-69 ◽  
Author(s):  
Lucas Marchi da Motta ◽  
Elírio Ernestino Toldo ◽  
Luiz Emílio de Sá ◽  
Brito de Almeida ◽  
José Carlos Nunes
Keyword(s):  
Coastal Zone ◽  
Rio Grande ◽  
Sediment Budget ◽  
Sandy Sediment ◽  
Rio Grande Do Sul ◽  
Littoral Drift ◽  
Littoral Cell ◽  
Dune Field ◽  
Engineering Research ◽  
Longshore Transport

Calculation of the coastal sediment budget involves estimation of the timing and intensity of processes of erosion, transport, and deposition, as well as an understanding of local and regional sediment dynamics. The modern sedimentary deposits present in the coastal zone constitute the physical basis of coastal ecosystems. Knowledge of the dynamics of these sediments from the source to sink area, through regional sediment management, is critical to understanding the long-term stability of the coastal zone and the fate of these important natural resources. In this article, the littoral cell concept has been applied to the midcoast of Rio Grande do Sul, a wave-dominated and dissipative-intermediate sandy coast in southern Brazil. To analyze littoral drift variations along the 275 km long study area, the shoreline was divided into 12 cells. Littoral drift rates were estimated and compared using the energy flux method. Wave parameters were obtained from WAVEWATCH III. The sand volume of the coastal dune field (4.20 billion m3) was quantified using satellite imagery and the aeolian transport rates estimated utilizing the sediment budget residual. The net annual longshore transport rates obtained with the Coastal Engineering Research Center equation range from 0.60 to 2.63 million m3 per year. The littoral drift rates obtained with the Van Rijn (2001) and Kamphuis (1991) equations range between 0.15 and 1.00 million m3 per year. Based on the sediment budget and dune field age, the CERC formula seems more appropriate to estimate longshore transport.

scholarly journals Sediment Transport and Water Flow Resistance in Alluvial River Channels: Modified Model of Transport of Non-Uniform Grain-Size Sediments

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2038
Author(s):  
Gennady Gladkov ◽  
Michał Habel ◽  
Zygmunt Babiński ◽  
Pakhom Belyakov
Keyword(s):  
Sediment Transport ◽  
Water Flow ◽  
Transport Model ◽  
Flow Characteristics ◽  
Field Measurements ◽  
Field Investigation ◽  
Empirical Modeling ◽  
River Channels ◽  
Channel Deformations ◽  
East European

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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