Subsurface characterization and prediction of land subsidence for HCM City, Vietnam

Thoang, Ta Thi; Giao, Pham Huy

doi:10.1016/j.enggeo.2015.10.009

Cited by 57 publications

(24 citation statements)

References 8 publications

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“…For the Mekong delta only limited data is available to constrain OCRs. Hoang et al (2016) found an average OCR value of 1.6 for clayey deposits in the Mekong delta and Thoang and Giao (2015) reported a similar value for medium to stiff clays in HCMC province. Validation of modeled subsidence in the Mekong delta with InSAR-derived subsidence rates from 2006-2010 (Erban et al 2014) revealed an almost similar OCR value of 1.63 to provide the best fit (Minderhoud et al 2017).…”

Section: Subsidence Calculationsmentioning

confidence: 90%

Groundwater extraction may drown mega-delta: projections of extraction-induced subsidence and elevation of the Mekong delta for the 21st century

Minderhoud

Middelkoop

Erkens

et al. 2020

Environ. Res. Commun.

100

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The low-lying and populous Vietnamese Mekong delta is rapidly losing elevation due to accelerating subsidence rates, primarily caused by increasing groundwater extraction. This strongly increases the delta's vulnerability to flooding, salinization, coastal erosion and, ultimately, threatens its nearly 18 million inhabitants with permanent inundation. We present projections of extraction-induced subsidence and consequent delta elevation loss for this century following six mitigation and nonmitigation extraction scenarios using a 3D hydrogeological model with a coupled geotechnical module. Our results reveal the long-term physically response of the aquifer system following different groundwater extraction pathways and show the potential of the hydrogeological system to recover. When groundwater extraction is allowed to increase continuously, as it did over the past decades, extraction-induced subsidence has the potential to drown the Mekong delta single-handedly before the end of the century. Our quantifications also disclose the mitigation potential to reduce subsidence by limiting groundwater exploitation and hereby limiting future elevation loss. However, the window to mitigate is rapidly closing as large parts of the lowly elevated delta plain may already fall below sea level in the coming decades. Failure to mitigate groundwater extraction-induced subsidence may result in mass displacement of millions of people and could severely affect regional food security as the food producing capacity of the delta may collapse.

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Section: Subsidence Calculationsmentioning

confidence: 90%

Groundwater extraction may drown mega-delta: projections of extraction-induced subsidence and elevation of the Mekong delta for the 21st century

Minderhoud

Middelkoop

Erkens

et al. 2020

Environ. Res. Commun.

100

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“…As InSAR is unable to measure areas lacking clear reflectors, such as rural areas that constitute most of the MKD, the analyses only cover part of the delta. Local 1D subsidence calculations as a function of measured groundwater drawdown have been performed for point locations in the MKD ( Erban et al 2014 ), Ca Mau city ( Karlsrud and Vangelsten 2017 ) and HCMC ( Thoang and Giao 2015 ). Interpolation maps based on such subsidence calculations from sparse groundwater monitoring well locations fail to reproduce the actual situation, since factors that influence subsidence locally, such as spatial heterogeneity of the delta subsurface and variability in the hydrogeological situation, are unaccounted for.…”

Section: Introductionmentioning

confidence: 99%

Impacts of 25 years of groundwater extraction on subsidence in the Mekong delta, Vietnam

Minderhoud

Erkens

Pham

et al. 2017

Environ. Res. Lett.

303

257

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Many major river deltas in the world are subsiding and consequently become increasingly vulnerable to flooding and storm surges, salinization and permanent inundation. For the Mekong Delta, annual subsidence rates up to several centimetres have been reported. Excessive groundwater extraction is suggested as the main driver. As groundwater levels drop, subsidence is induced through aquifer compaction. Over the past 25 years, groundwater exploitation has increased dramatically, transforming the delta from an almost undisturbed hydrogeological state to a situation with increasing aquifer depletion. Yet the exact contribution of groundwater exploitation to subsidence in the Mekong delta has remained unknown. In this study we deployed a delta-wide modelling approach, comprising a 3D hydrogeological model with an integrated subsidence module. This provides a quantitative spatially-explicit assessment of groundwater extraction-induced subsidence for the entire Mekong delta since the start of widespread overexploitation of the groundwater reserves. We find that subsidence related to groundwater extraction has gradually increased in the past decades with highest sinking rates at present. During the past 25 years, the delta sank on average ∼18 cm as a consequence of groundwater withdrawal. Current average subsidence rates due to groundwater extraction in our best estimate model amount to 1.1 cm yr−1, with areas subsiding over 2.5 cm yr−1, outpacing global sea level rise almost by an order of magnitude. Given the increasing trends in groundwater demand in the delta, the current rates are likely to increase in the near future.

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“…Similar cases in surrounding countries have led to serious consequences of subsidence such as in Bangkok where severe overexploitation of groundwater resulted in areas sinking up to 1.0 m below the mean sea level which has drastically increased the risk of flooding events (Phien-wej et al, 2006). Current and future infrastructure needs to be adapted to withstand differential settlements such as with the development of new MRT lines in Ho Chi Minh City (Thoang and Giao, 2015) or the hampered development of sustainable economic zones in the Hong Kong environment (Chen et al, 2012). Finally, degradation of the aquifer system poses challenges for future water availability like in the Rafsanjan plain (Motagh et al, 2017).…”

Section: Potential Impactmentioning

confidence: 99%

“…Yangon city is an example of such a delta city where 5 million inhabitants are confronted with the negative effects of groundwater extraction such as seen in cities such as Bangkok (Phien-wej et al, 2006), Shanghai (Chai et al, 2004), the Hong Kong surroundings (Chen et al, 2012), and Ho Chi Minh City (Thoang and Giao, 2015). In Yangon City, groundwater is the most significant source of water supply (JICA, 2014b) which means that subsidence can be expected.…”

Section: Introductionmentioning

confidence: 99%

Monitoring land subsidence in Yangon, Myanmar using Sentinel-1 persistent scatterer interferometry and assessment of driving mechanisms

Horst

Rutten

Giesen

et al. 2018

Remote Sensing of Environment

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Inhabitants and ecosystems in delta areas are becoming increasingly vulnerable to the effects of subsidence, caused by anthropogenic activities. Yangon is a city on the periphery of the Irrawaddy delta in Myanmar where little is known about the true extent of this hazard, while its effects can potentially harm millions of its inhabitants. This research presents the magnitude and extent of the subsidence hazard in Yangon through a Persistent Scatterer Interferometry (PSI) time-series analysis on the Sentinel-1 data archives in the period of December 2015 through April 2017. The PSI analysis revealed four distinct zones of varying sizes where vertical velocity differences over 20 mm/yr were found, locally exceeding 110 mm/yr. The significant subsidence zones are exclusively located in young Alluvium deposits and 95% of velocity differences over 10 mm/yr are found at Quaternary age deposits. The addition of loads, such as buildings, predominantly affect subsidence rates in the first decade after placement. Estimates of groundwater extraction for domestic supply, used by more than 2 million inhabitants, correlate with the township average subsidence rates which shows that most subsidence in Yangon can be explained by groundwater extraction. Current operation of groundwater extraction wells induces an aquifer volume loss of 5.5 million cubic meter per year in the aquifer system of Yangon city. Unless groundwater extractions are mitigated, Yangon will be increasingly vulnerable to infrastructural damages, flooding events, and degrading aquifer quality.

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Subsurface characterization and prediction of land subsidence for HCM City, Vietnam

Cited by 57 publications

References 8 publications

Groundwater extraction may drown mega-delta: projections of extraction-induced subsidence and elevation of the Mekong delta for the 21st century

Groundwater extraction may drown mega-delta: projections of extraction-induced subsidence and elevation of the Mekong delta for the 21st century

Impacts of 25 years of groundwater extraction on subsidence in the Mekong delta, Vietnam

Monitoring land subsidence in Yangon, Myanmar using Sentinel-1 persistent scatterer interferometry and assessment of driving mechanisms

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