75. THEORY AND FIELD TEST OF BEACH NOURISHMENT USING COARSE SAND AND GRAVEL

2009 ◽  
Author(s):  
Takayuki Kumada ◽  
Takaaki Uda ◽  
Toshinori Ishikawa
Keyword(s):  
Field Test ◽  
Beach Nourishment ◽  
Coarse Sand ◽  
Sand And Gravel

scholarly journals Artificial Intelligence Application on Sediment Transport

2021 ◽  
Vol 9 (6) ◽  
pp. 600
Author(s):  
Hyun Dong Kim ◽  
Shin-ichi Aoki
Keyword(s):  
Sediment Transport ◽  
Numerical Models ◽  
Beach Nourishment ◽  
Hydraulic Model ◽  
Alternative Methods ◽  
Cross Sectional ◽  
Sand And Gravel ◽  
Incident Waves ◽  
Artificial Intelligence Application ◽  
Deep Learning Model

When erosion occurs, sand beaches cannot maintain sufficient sand width, foreshore slopes become steeper due to frequent erosion effects, and beaches are trapped in a vicious cycle of vulnerability due to incident waves. Accordingly, beach nourishment can be used as a countermeasure to simultaneously minimize environmental impacts. However, beach nourishment is not a permanent solution and requires periodic renourishment after several years. To address this problem, minimizing the period of renourishment is an economical alternative. In the present study, using the Tuvaluan coast with its cross-sectional gravel nourishment site, four different test cases were selected for the hydraulic model experiment aimed at discovering an effective nourishment strategy to determine effective alternative methods. Numerical simulations were performed to reproduce gravel nourishment; however, none of these models simultaneously simulated the sediment transport of gravel and sand. Thus, an artificial neural network, a deep learning model, was developed using hydraulic model experiments as training datasets to analyze the possibility of simultaneously accomplishing the sediment transport of sand and gravel and supplement the shortcomings of the numerical models.

scholarly journals DRAINAGE OF AN IRRIGATED SALINE SOIL IN ALBERTA

1982 ◽  
Vol 62 (2) ◽  
pp. 387-396
Author(s):  
D. R. BENNETT ◽  
G. R. WEBSTER ◽  
B. A. PATERSON ◽  
D. B. HARKER
Keyword(s):  
Water Table ◽  
Crop Production ◽  
Saline Soil ◽  
Soil Depth ◽  
Drainage System ◽  
High Water ◽  
Coarse Sand ◽  
Irrigation Period ◽  
Dilution Effects ◽  
Sand And Gravel

A shallow subsurface drainage system effectively controlled a high water table and reduced salinity in an irrigated soil near Magrath, Alberta. Plastic corrugated tubing was installed in 1976 at depths of 1.1–1.5 m and spacings of 15 and 30 m in a moderately saline soil. During the irrigation period, the water table rose to within 0.3 m of the surface but was lowered to pre-irrigation levels within 48 h. The water table was maintained at, or below, the depth of the drains between irrigations. The 15- and 30-m spacings of the drain lines were equally effective in providing water table control in this lacustrine soil which was underlain by a coarse sand and gravel layer. Salinity levels were decreased substantially only within the surface 0.3-m soil depth. Quality of the drainage effluent remained constant throughout the growing season with only small dilution effects detected during irrigations. Barley yields increased to 3900 kg/ha in 1978, 2 yr following drainage of this saline soil which had been out of crop production for 20 yr.

scholarly journals Anisotropic Shear Strength Behavior of Soil–Geogrid Interfaces

2021 ◽  
Vol 11 (23) ◽  
pp. 11387
Author(s):  
Jun Zhang ◽  
Mingchang Ji ◽  
Yafei Jia ◽  
Chenxi Miao ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Great Influence ◽  
Fine Sand ◽  
Coarse Sand ◽  
Shear Direction ◽  
Interface Shear Strength ◽  
Interface Shear ◽  
Strength Behavior ◽  
Sand And Gravel

This paper presents an experimental study on the anisotropic shear strength behavior of soil–geogrid interfaces. A new type of interface shear test device was developed, and a series of soil–geogrid interface shear tests were conducted for three different biaxial geogrids and three different triaxial geogrids under the shear directions of 0°, 45° and 90°. Clean fine sand, coarse sand, and gravel were selected as the testing materials to investigate the influence of particle size. The experimental results for the interface shear strength behavior, and the influences of shear direction and particle size are presented and discussed. The results indicate that the interface shear strength under the same normal stress varies with shear direction for all the biaxial and triaxial geogrids investigated, which shows anisotropic shear strength behavior of soil–geogrid interfaces. The soil–biaxial geogrid interfaces show stronger anisotropy than that of the soil–triaxial geogrid interfaces under different shear directions. Particle size has a great influence on the anisotropy shear strength behavior of soil–geogrid interfaces.

scholarly journals Taxonomy and Ecology of Sympatric Ampelisca Species (Crustacea, Amphipoda) From the Strait of Gibraltar to the Strait of Dover, North-Eastern Atlantic

2021 ◽  
Vol 8 ◽  
Author(s):  
Jean-Claude Dauvin ◽  
Leandro Sampaio ◽  
Ana Maria Rodrigues ◽  
Victor Quintino
Keyword(s):  
Continental Shelf ◽  
Sea Water ◽  
Atlantic Coast ◽  
Coarse Sand ◽  
Strait Of Gibraltar ◽  
The North ◽  
Atlantic Province ◽  
Regional Area ◽  
North Eastern ◽  
Sand And Gravel

The Ampeliscidae Kröyer, 1842 is amongst the most diverse amphipod families; it comprises four genera, Ampelisca being the richest with more than 200 species. The Ampelisca genus presents high morphological homogeneity and the identification of the species by ecologists remains difficult. Ampelisca are also characterized by a high degree of sympatry, a rare situation in amphipods, and in this study we report up to nine species coexisting at the same site. Recent benthic sampling and publications, namely on the Portuguese continental shelf and the English Channel, permit to revisit the available data on the taxonomy and propose an updated species identification key, as well as the distribution and ecology of the 40-recorded Ampelisca species along the North Eastern Atlantic coast, from the Strait of Gibraltar, in the South, to the Strait of Dover, in the North. The data allow discussing on the sympatry and syntopy of such diverse amphipod family with the co-occurrence of several species at various scales of observations, from the wider regional area, to the narrower local habitat. Two Ampelisca species were recorded exclusively on hard bottom, while the other tend to inhabit specific types of soft bottom, ranging from deep mud to shallow coarse sand and gravel, with a preference for continental shelf muddy and sandy habitats. A future sea water temperature increase scenario could modify the species geographical distribution and reproductive cycle, in this temperate North-eastern Atlantic province.

scholarly journals Evaluation of Effect of Beach Nourishment using Fine and Coarse Sand by Contour-line-change Model Considering Change in Grain Size

2007 ◽  
Vol 54 ◽  
pp. 641-645
Author(s):  
Takaaki UDA ◽  
Takayoshi YOSHIZOE ◽  
Yasushi MACHII ◽  
Takeshi YAMAMOTO ◽  
Kou FURUIKE ◽  
...  
Keyword(s):  
Grain Size ◽  
Beach Nourishment ◽  
Coarse Sand ◽  
Contour Line ◽  
Change Model

scholarly journals Analysis of the presence of glyphosate in sediments from the hydrographic basin dam of the São João stream in the municipality of Porto Nacional, Tocantins

2020 ◽  
Vol 13 (3) ◽  
pp. 43-51
Author(s):  
Patricia Oliveira Godinho ◽  
Angelo Ricardo Balduino
Keyword(s):  
Particle Size ◽  
Agricultural Production ◽  
Total Sample ◽  
Coarse Sand ◽  
Agricultural Activity ◽  
Hydrographic Basin ◽  
Average Value ◽  
Chemical Products ◽  
Sand And Gravel

Agricultural production has been one of the activities that most affect the quality of fresh water, due to accelerated urbanization, as well as the growing agricultural production in the region such as corn and soy in order to meet the high consumption demanded by the population, such activities have influenced drastically hydrographic basin conditions due to the excessive use of pesticides. Among the consequences caused are soil erosion, silting, increased production of sediments as well as water turbidity. Through studies related to sediments, it was possible to notice that their structures retain most of the chemical products, through the processes of adsorption, infiltration, and sorption in the soil. This in fact resulted in a study to assess the quality of the São João stream hydrographic basin, which covers the city of Porto Nacional Tocantins, being the main source of surface supply. With the main objective of analyzing the manifestations of chemical products resulting from agricultural use through the collection of sediment samples from the São João stream dam to check the presence of glyphosate, in addition to soil particle size characterization, for particle size classification. From the results obtained in the laboratory, it was observed that the soil presented a high granulometric variation, which despite containing a small percentage of fines such as silt, most of the sample consists of medium sand, coarse sand and gravel responsible for 86.66 % of the total sample. The result obtained an average value of 0.02 μg / L. Then, the results were compared to the values specified by the environmental legislation, in its resolution 357/2005 of the National Environment Council. The values showed the manifestation of the herbicide present in the sample, contacting the vulnerability of water resources, as a result of the poor management of the hydrographic basin, in which the concentrations of agrochemical chemical glyphosate did not show results superior to those allowed by the CONAMA resolution 307/2005. However, due to the growing agricultural activity in the region, this must be periodically evaluated so that it does not reach alarming numbers, subsequently harming water quality.

scholarly journals Habitat Preferences of PokeA (Batissa violacea var. celebensis von Martens, 1897) Basic on Substrat Characterisation in Pohara River Southeast Sulawesi

2020 ◽  
Vol 4 (2) ◽  
pp. 74-82
Author(s):  
Bahtiar Bahtiar ◽  
Muh. Fajar Purnama
Keyword(s):  
Habitat Preferences ◽  
Principal Component ◽  
Coarse Sand ◽  
Sediment Texture ◽  
Chi Square ◽  
Multivariate Statistical ◽  
Entire Cross Section ◽  
Lack Of Information ◽  
And Cluster Analysis ◽  
Sand And Gravel

This research is motivated by the lack of information about the habitat preferences of pokea clams in Pohara River, Southeast Sulawesi. This study aims to determine the density, distribution pattern and habitat preferences of pokea clams in the Pohara River, Southeast Sulawesi. This research was conducted for 6 months (April-September 2011). Sampling of pokea, water quality, and sediment texture was carried out in the Pohara River and analyzed at the FPIK UHO Laboratory. The density and distribution of pokea were calculated using a standard formula and analyzed using Mann Whitney and Chi Square respectively, while the habitat preferences based on different substrate textures were analyzed using Principal Component Analysis (PCA) and Cluster Analysis (CA) in the Multivariate Statistical Package (MVSP). The results showed that the density of pokea clams ranged from 117±96.78-816±594.84 ind/m2 which was distributed in cluster over the entire cross-section of the river. Pokea clams were found in all substrate textures from gravel to clay. The habitat preference of pokea clams indicated by the highest density was found in the clay texture. Pokea clams relatively do not like the habitat of coarse sand and gravel texture which is characterized by pokea population with the lowest density

Overbank deposits of the Narrator Brook, Dartmoor, England

1981 ◽  
Vol 118 (1) ◽  
pp. 77-82
Author(s):  
B. Gomez ◽  
P. C. Sims
Keyword(s):  
Coarse Sand ◽  
Drainage Ditch ◽  
Stages Of Development ◽  
Fine Silt ◽  
The Third ◽  
Coarse Sediment ◽  
Three Stages ◽  
Sand And Gravel ◽  
Crevasse Splay ◽  
Peat Horizon

SummaryOverbank deposits of the Narrator Brook, exposed by the excavation of a drainage ditch, are described. The deposits, which consist of coarse (sand and gravel), fine (silt and clay) and peat units, were laid down in a floodbasin environment. The coarse units are interpreted as crevasse-splay deposits, rather than being classified as floodbasin sediments along with the fine units. Three stages of development in the evolution of the floodbasin are identified. The first stage is represented by the development of peat at a time when the area was not subjected to flooding, the second by deposition of the fine and coarse sediment units and the third by an upper peat horizon. No precise date for the formation of the deposits is at present available, but it is thought that they may be the result of man's activity in the catchment.

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