Relationship between flood severity and risk of hospitalisation in the Mekong River Delta of Vietnam

ObjectiveTo examine the relationship between flood severity and risk of hospitalisation in the Vietnam Mekong River Delta (MRD).MethodsWe obtained data on hospitalisations and hydro-meteorological factors during 2011–2014 for seven MRD provinces. We classified each day into a flood-season exposure period: the 2011 extreme annual flood (EAF); 2012–2014 routine annual floods (RAF); dry season and non-flood wet season (reference period). We used province-specific Poisson regression models to calculate hospitalisation incidence rate ratios (IRRs). We pooled IRRs across provinces using random-effects meta-analysis.ResultsDuring the EAF, non-external cause hospitalisations increased 7.2% (95% CI 3.2% to 11.4%); infectious disease hospitalisations increased 16.4% (4.3% to 29.8%) and respiratory disease hospitalisations increased 25.5% (15.5% to 36.4%). During the RAF, respiratory disease hospitalisations increased 8.2% (3.2% to 13.5%). During the dry season, hospitalisations decreased for non-external causes and for each specific cause except injuries.ConclusionsWe observed a gradient of decreasing risk of hospitalisation from EAF to RAF/non-flood wet season to dry season. Adaptation measures should be strengthened to prepare for the increased probability of more frequent extreme floods in the future, driven by climate change.

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Mechanism of Formation and Estuarine Turbidity Maxima in the Hau River Mouth

Water ◽

10.3390/w12092547 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2547

Author(s):

Nguyen Ngoc Tien ◽

Dinh Van Uu ◽

Do Huy Cuong ◽

Le Dinh Mau ◽

Nguyen Xuan Tung ◽

...

Keyword(s):

Sediment Transport ◽

Suspended Sediment ◽

Dry Season ◽

River Delta ◽

Mekong River ◽

Suspended Sediment Transport ◽

Mechanism Of Formation ◽

Mekong River Delta ◽

Flood Season ◽

Estuarine Turbidity Maxima

Observation of the Hau River distributary of the Mekong River delta in Vietnam, conducted in dry and flood season (2009, 2014, and 2015), is utilized to investigate the mechanism of formation, distribution of estuarine turbidity maxima (ETM), and links with sediment transport in the system. Additionally, 3D (three-dimensional) numerical models are applied to simulate the seasonal tidal variation (flood and dry seasons) of the water and suspended sediment transport processes of the Mekong River Delta. The 3D model, with a combination of hydrodynamic-wave and suspended sediment transport, was set up and validated with measured data in the study area. The mechanism that measures ETM is the process of suspended sediment from the river when it interacts with seawater and speeds up the flocculation, combined with the asymmetry of the tidal current, which will create the region with ETM by moving in/out with the tidal current’s ups and downs. As there is surface flow velocity towards the sea, the bottom baroclinic flow has a decisive role in deposition and erosion, and it causes the suspended sediment concentration (SSC) to be maximized. During the flood season, the salt wedge near the river’s mouth, at the peak of the tide, pushes towards the sea’s direction when there are ebbing tides, with a scope of about 20 km. In the dry season, there is estuary disturbance as well; the salt wedge forms, but is relatively weak or does not exist, depending on the time of the tide. The maximum turbidity zone in the flood season moves the subaqueous delta with a scope of about 20 km and SSC of about 0.1 to 0.6 g L−1, whereas in the dry season, the seawater has high salinity, and seaward SSC penetrates the estuaries to cause a disturbance and flocculation. The penetration scope is up to 50 km and creates a water mass that has high SSC, from 0.2 to 0.7 g L−1, to run in/off by the tidal current’s ups and downs for several kilometers in the tidal phase.

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SOME SOLUTIONS TO RESPOND CLIMATE CHANGE FOR THE MEKONG DELTA, VIET NAM

GeoScience Engineering ◽

10.1515/gse-2017-0013 ◽

2017 ◽

Vol 63 (3) ◽

pp. 18-24

Author(s):

Nguyen Thuy Lan Chi ◽

Phan Dao ◽

Microslav Kyncl

Keyword(s):

Climate Change ◽

Forest Fires ◽

Mekong Delta ◽

River Delta ◽

Mekong River ◽

Adaptation Measures ◽

Mekong River Delta ◽

Low Levels ◽

Negative Impacts ◽

Impacts Of Climate Change

Abstract In the recent decades, the Mekong River Delta has suffered quite significant impacts of climate change. Fluctuations of weather elements and sea level rises have caused adverse changes, namely: the appearance of unusual high and low levels of annual floods, more and more intense storms, more severe droughts, forest fires, river erosion, cyclones, and tidal surges appear increasingly more dangerous. Traditional adaptation measures to the environmental conditions may be unsuitable in the context of climate change in the Mekong River Delta. This paper summarizes some of the new adaptation measures that scientists and policy planners have proposed for the area to cope with the negative impacts of climate change.

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