scholarly journals Coupling hydrological–hydraulic models for extreme flood simulating and forecasting on the North Central Coast of Vietnam

2009 ◽  
Author(s):  
H. Van Lai ◽  
N. Van Diep ◽  
N. T. Cuong ◽  
N. H. Phong
2021 ◽  
Vol 9 (08) ◽  
pp. 505-514
Author(s):  
Nguyen Chi Mai ◽  
◽  
NinhThi Ngoc ◽  
Nguyen Xuan Cuong ◽  
Nguyen Hoai Nam ◽  
...  

Vietnam contains diverse marine ecosystems with the high biodiversity of marine organisms, including gorgonian corals of Alcyonacea order. In order to support traditional classification of these corals, in this study mitochondrial barcoding markers msh1 and nuclear 28S rDNA were developed for analysis of 11 specimens collected in 2015 and 2016 from different islands and bays along the North Central coast of Vietnam. Phylogenetic analyses based on msh1 and 28S sequence polymorphism showed that all specimens belonged to Anthozoa class, Octocorallia sub-class and Alcyonacea order. At lower taxa levels, they were divided into 4 sub-orders, 7 families and 7 genera according to 7 distinct clades with bootstrap values from 99-100%.The identifications of 7 out of 11 specimens including Sinularia brassica (2 specimens)and Sinularialeptoclados, Dichotellagemmacea, Annella reticulata, S. conferta and S. nanolobata were in concordance between morphological and molecular methods. The other 4 specimens were only identified at genus levels of Astrogorgia sp., Melithaea sp. Scleronephthya sp. and Muricella sp. by either msh1-morphology or msh1-28S markers. These results highlight the importance of molecular markers to elucidate patterns of biodiversity and species identification of soft coral.


2020 ◽  
Vol 10 (3) ◽  
pp. 5648-5654
Author(s):  
D. D. Cham ◽  
N. T. Son ◽  
N. Q. Minh ◽  
N. T. Hung ◽  
N. Tien Thanh

An extremely dynamic morphology of the estuary is observed in the coastal regions of Vietnam under the governing processes of tides, waves, and river system flows. The primary target of this paper is to provide insight into the governing processes and morphological behavior of the NhatLe estuary, located in the north-central coast of Vietnam. Based on measured data from field surveys and satellite images combined with numerical model simulations of MIKE and Delft3D, the influences of seasonal river flow, tides, and wave dynamics on the sediment transport and morphological changes are fully examined. The study showed that freshwater flow in the flood season plays a central role in cutting off the southern sandspit, maintain and shaping the main channel. The prevailing waves in winter and summer induce longshore drift and sediment transport in the southeast to northwest direction. In the low flow season, this longshore sediment transport is dominant, causing sediment to deposit on the southern side of the ebb tidal delta and elongating the southern sandspit which narrows the estuary entrance and reorients the main channel.


2021 ◽  
Vol 9 (3) ◽  
pp. 739-744 ◽  
Author(s):  
Tho Nguyen Gia ◽  
My Mai Bac ◽  
Vien Le Van

In any given supply chain, risks can occur, and it can reduce the performance of an entire production line. To maintain a competitive advantage, manufacturers should anticipate and manage risks. This paper aims to assess the impact of risks associated with the fishery supply chain on logistics performance. The research was conducted with 297 seafood producers on the North Central Coast of Vietnam. The study results show that risk factors such as supply risks, market risks, operational risks, environmental risks, and financial risks have a direct impact on the logistical performance of firms in the fishery supply chain. The study also proposes solutions to limit risks for businesses.


2021 ◽  
pp. 2222-2238
Author(s):  
Nguyen Thi Nu ◽  
Nguyen Thanh Duong ◽  
Bui Truong Son

     The North Central Coast of Vietnam has a wide distribution of loose sand which is often exposed on the surface. The thickness changes from a few meters to over ten meters. This sand with the loose state can be sensitive to the dynamic loads, such as earthquakes, traffic load, or machine foundations. It can be liquefied under these loadings, which might destroy the ground and buildings. The Standard Penetration Test (SPT) is widely used in engineering practice and its values can be useful for the assessment of soil liquefaction potential. Thus, this article presents some ground profiles in some sites in the North Central Coast of Vietnam and determines the liquefaction potential of sand based on SPT and using three parameters, including the Factor of Safety against Liquefaction (FSLIQ), Liquefaction Potential Index (LPI), and Liquefaction Severity Number (LSN). The research results show that the FSLIQ, LPI, and LSN values depend on the depth of sand samples and the SPT values. In this study, the sand distributed from 2.0 to 18.0m with (N1)60cs value of less than 20 has high liquefaction potential with FSLIQ<1, LPI is often higher than 0.73, and LSN is often higher than 10. The results also show that many soil profiles have high liquefaction potential. These results should be considered for construction activities in this area.


Tropics ◽  
2016 ◽  
Vol 24 (4) ◽  
pp. 169-180 ◽  
Author(s):  
Thi Thuy Phuong Nguyen ◽  
Misa Masuda ◽  
Seiji Iwanaga

2005 ◽  
Vol 119 (3) ◽  
pp. 412 ◽  
Author(s):  
Sarah W. Lansing

Rock Voles (Microtus chrotorrhinus) were previously documented only from the southern coast of Labrador and the Strait of Belle Isle south of Hamilton Inlet. During two field seasons in 2000 and 2001, both in July, six Rock Vole specimens were collected on Southern Island, off the north-central coast of Labrador, extending the range of the subspecies Microtus chrotorrhinus ravus approximately 250 km to the central Labrador coast north of Hamilton Inlet. Rock Voles were trapped primarily in stunted Black Spruce (Picea mariana) forest and areas associated with rocks, thick brush, and water.


Author(s):  
Nguyen Thi Hoang Anh ◽  
Mai Kim Lien

Climate change is driving dangerous and more unpredictable weather. It has broken historical records of hydro-meteorological observations, consequently leading challenges in operational forecasting. In order to improve crop yield and reduce impacts of climate change on agricultural production, it is necessary to obtain sources of weather information. The estimations of rainfall and PET can enable us to identify plant growth and water supply capacity for any plant in the mountainous areas at Quy Hop District, Nghe An (one part of the North Central Coast) on a monthly basis. The updated information on weather forecasting technology and the application of modern technology responding to climate change in Quy Hop provided results related to cumulative rainfall chart. It can forecast accurately the plant growth and the best time for watering plants and plays an important role in the agricultural production.  


2020 ◽  
Vol 8 (9) ◽  
pp. 722
Author(s):  
Nguyen Quang Duc Anh ◽  
Hitoshi Tanaka ◽  
Ho Sy Tam ◽  
Nguyen Xuan Tinh ◽  
Tran Thanh Tung ◽  
...  

Tidal inlets along the central coast of Vietnam are located in a microtidal, wave-dominated coastal environment. In addition, the Vietnam coast is highly influenced by the seasonal monsoon regime, which is characterized by large northeast waves from October to March and calm southeast waves from April to September every year. Consequently, the tidal inlet entrance morphologies often suffer from a dynamic seasonal evolution due to distinct differences in the direction of wave-induced longshore sediment transport (LST) between the two monsoon seasons. The migration or closure of tidal inlets causes a lot of problems for socio-economic development in the region since these are the main reasons leading to an increase in the risk of coastal flooding and the obstruction of navigation. This paper presents a comprehensive study of the morphological evolutions of natural tidal inlets on the central coast of Vietnam using long-term remote sensing data sets and by the Delft3D numerical model. Surprisingly, the estimated LST rates from the former method are in an order of magnitude agreement with the results from the latter one for all of the areas in this study. Based on the conservation equation for sand and comprehensive data collection, a new simple empirical formula for predicting the sand spit elongation rate as a function of the sand spit width is developed. Although the breaching of sand spit might happen during an extreme flood event at some tidal inlets, the growth rate of the spit before and after the breaching is almost unchanged. These findings are very useful information for supporting the local coastal authorities to find better management solutions in terms of sustainable development.


1996 ◽  
Vol 7 (4) ◽  
pp. 341-353 ◽  
Author(s):  
Thomas Pozorski ◽  
Shelia Pozorski

Recent investigations in the Casma Valley on the north-central coast of Peru have uncovered a series of circular and rectangular/square structures, each containing a central hearth associated with either four subfloor ventilation shafts or a single open ventilation trough. The structures date to the Late Preceramic period (2500-1800 B. C.) and the Initial period (1800-900 B. C.). All are small and were originally roofed with perishable materials to hold in heat and smoke from the central hearth. It seems likely that these ventilated hearths represent a coastal variant of the Kotosh Religious Tradition that has been well documented in the Peruvian Highlands. The structures probably served as ritual chambers for small groups of people, somewhat analogous to the sweathouses of various Native American groups.


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