scholarly journals Tidal amplification and salt intrusion in the Mekong Delta driven by anthropogenic sediment starvation

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sepehr Eslami ◽  
Piet Hoekstra ◽  
Nam Nguyen Trung ◽  
Sameh Ahmed Kantoush ◽  
Doan Van Binh ◽  
...  
Keyword(s):  
Climate Change ◽  
Natural Resources ◽  
Sea Level Rise ◽  
Sea Level ◽  
Saline Water ◽  
Mekong Delta ◽  
Sediment Supply ◽  
Tidal Amplitude ◽  
Irreversible Damage ◽  
Tidal Amplification

AbstractNatural resources of the Mekong River are essential to livelihood of tens of millions of people. Previous studies highlighted that upstream hydro-infrastructure developments impact flow regime, sediment and nutrient transport, bed and bank stability, fish productivity, biodiversity and biology of the basin. Here, we show that tidal amplification and saline water intrusion in the Mekong Delta develop with alarming paces. While offshore M2 tidal amplitude increases by 1.2–2 mm yr−1 due to sea level rise, tidal amplitude within the delta is increasing by 2 cm yr−1 and salinity in the channels is increasing by 0.2–0.5 PSU yr−1. We relate these changes to 2–3 m bed level incisions in response to sediment starvation, caused by reduced upstream sediment supply and downstream sand mining, which seems to be four times more than previous estimates. The observed trends cannot be explained by deeper channels due to relative sea level rise; while climate change poses grave natural hazards in the coming decades, anthropogenic forces drive short-term trends that already outstrip climate change effects. Considering the detrimental trends identified, it is imperative that the Mekong basin governments converge to effective transboundary management of the natural resources, before irreversible damage is made to the Mekong and its population.

Feasibility of sedimentation strategies for the Mekong delta to counterbalance relative sea-level rise

2021 ◽  
Author(s):  
Frances E. Dunn ◽  
Philip S. J. Minderhoud
Keyword(s):  
Land Use ◽  
Sea Level Rise ◽  
Sea Level ◽  
Mekong Delta ◽  
Sediment Deposition ◽  
Sediment Supply ◽  
Sediment Flux ◽  
Relative Sea Level ◽  
Fluvial Sediment ◽  
Relative Sea Level Rise

<p>As one of the largest deltas in the world, the Mekong delta is home to over 17 million people and supports internationally important agriculture. Recently deposited sediment compacts and causes subsidence in deltas, so they require regular sediment input to maintain elevation relative to sea level. These processes are complicated by human activities, which prevent sediment deposition indirectly through reducing fluvial sediment supply and directly through the construction of flood defence infrastructure on deltas, impeding floods which deliver sediment to the land. Additionally, anthropogenic activities increase the rate of subsidence through the extraction of groundwater and other land-use practices.</p><p>This research shows the potential for fluvial sediment delivery to compensate for sea-level rise and subsidence in the Mekong delta over the 21st century. We use detailed elevation data and subsidence scenarios in combination with regional sea-level rise and fluvial sediment flux projections to quantify the potential for maintaining elevation relative to sea level in the Mekong delta. We present four examples of localised sedimentation scenarios in specific areas, for which we quantified the potential effectiveness of fluvial sediment deposition for offsetting relative sea-level rise. The presented sediment-based adaptation strategies are complicated by existing land use, therefore a change in water and sediment management is required to effectively use natural resources and employ these adaptation methods. The presented approach could be an exemplar to assess sedimentation strategy feasibility in other delta systems worldwide that are under threat from sea-level rise.</p>

Marsh Processes and Their Response to Climate Change and Sea-Level Rise

2019 ◽  
Vol 47 (1) ◽  
pp. 481-517 ◽  
Author(s):  
Duncan M. FitzGerald ◽  
Zoe Hughes
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Sea Level Rise ◽  
Suspended Sediment ◽  
Sea Level ◽  
Salt Marshes ◽  
Biomass Productivity ◽  
Sediment Supply ◽  
Marsh Vegetation ◽  
Suspended Sediment Concentrations

In addition to their being vital components of mid- to high-latitude coastal ecosystems, salt marshes contain 0.1% of global sequestered terrestrial carbon. Their sustainability is now threatened by accelerating sea-level rise (SLR) that has reached a rate that is many times greater than the rate at which they formed and evolved. Modeling studies have been instrumental in predicting how marsh systems will respond to greater frequencies and durations of tidal inundation and in quantifying thresholds when marshes will succumb and begin to disintegrate due to accelerating SLR. Over the short term, some researchers believe that biogeomorphic feedbacks will improve marsh survival through greater biomass productivity enhanced by warmer temperatures and higher carbon dioxide concentrations. Increased sedimentation rates are less likely due to lower-than-expected suspended sediment concentrations. The majority of marsh loss today is through wave-induced edge erosion that beneficially adds sediment to the system. Edge erosion is partly offset by upland marsh migration during SLR. ▪ Despite positive biogeomorphic feedbacks, many salt marshes will succumb to accelerating sea-level rise due to insufficient mineral sediment. ▪ The latest multivariate marsh modeling is producing predictions of marsh evolution under various sea-level rise scenarios. ▪ The least well-known variables in projecting changes to salt marshes are suspended sediment concentrations and net sediment influx to the marsh. ▪ We are in the infancy of understanding the importance and processes of marsh edge erosion and the overall dynamicism of marshes. ▪ This review defines the latest breakthroughs in understanding the response of salt marshes to accelerating sea-level rise and decreasing sediment supply. ▪ Climate change is accelerating sea-level rise, warming temperatures, and increasing carbon dioxide, all of which are impacting marsh vegetation and vertical accretion.

scholarly journals Sedimentation and Survival of the Mekong Delta: A Case Study of Decreased Sediment Supply and Accelerating Rates of Relative Sea Level Rise

Oceanography ◽  
2017 ◽  
Vol 30 (3) ◽  
pp. 98-109 ◽  
Author(s):  
Mead Allison ◽  
◽  
Charles Nittrouer ◽  
Andrea Ogston ◽  
Julia Mullarney ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Mekong Delta ◽  
Sediment Supply ◽  
Relative Sea Level ◽  
Relative Sea Level Rise

Transitioning to a Prosperous, Resilient and Carbon-Free Economy

2021 ◽  
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Natural Resources ◽  
Sea Level Rise ◽  
Sea Level ◽  
Climate Changes ◽  
Decision Makers ◽  
Extreme Weather Events ◽  
Early Adoption ◽  
Weather Events

This book is a comprehensive manual for decision-makers and policy leaders addressing the issues around human caused climate change, which threatens communities with increasing extreme weather events, sea level rise, and declining habitability of some regions due to desertification or inundation. The book looks at both mitigation of greenhouse gas emissions and global warming and adaption to changing conditions as the climate changes. It encourages the early adoption of climate change measures, showing that rapid decarbonisation and improved resilience can be achieved while maintaining prosperity. The book takes a sector-by-sector approach, starting with energy and includes cities, industry, natural resources, and agriculture, enabling practitioners to focus on actions relevant to their field. It uses case studies across a range of countries, and various industries, to illustrate the opportunities available. Blending technological insights with economics and policy, the book presents the tools decision-makers need to achieve rapid decarbonisation, whilst unlocking and maintaining productivity, profit, and growth.

scholarly journals Impacts of Human Activity and Global Changes on Future Morphodynamics within the Tien River, Vietnamese Mekong Delta

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2204
Author(s):  
Christian Jordan ◽  
Jan Visscher ◽  
Nguyen Viet Dung ◽  
Heiko Apel ◽  
Torsten Schlurmann
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Human Activity ◽  
Mekong Delta ◽  
Mining Activity ◽  
Baseline Scenario ◽  
Sand Mining ◽  
Future Period ◽  
Erosion And Deposition

The hydro- and morphodynamic processes within the Vietnamese Mekong Delta are heavily impacted by human activity, which in turn affects the livelihood of millions of people. The main drivers that could impact future developments within the delta are local stressors like hydropower development and sand mining, but also global challenges like climate change and relative sea level rise. Within this study, a hydro-morphodynamic model was developed, which focused on a stretch of the Tien River and was nested into a well-calibrated model of the delta’s hydrodynamics. Multiple scenarios were developed in order to assess the projected impacts of the different drivers on the river’s morphodynamics. Simulations were carried out for a baseline scenario (2000–2010) and for a set of plausible scenarios for a future period (2050–2060). The results for the baseline scenario indicate that the Tien River is already subject to substantial erosion under present-day conditions. For the future period, hydropower development has the highest impact on the local erosion and deposition budget, thus amplifying erosional processes, followed by an increase in sand mining activity and climate change-related variations in discharge. The results also indicate that relative sea level rise only has a minimal impact on the local morphodynamics of this river stretch, while erosional tendencies are slowed by a complete prohibition of sand mining activity. In the future, an unfavourable combination of drivers could increase the local imbalance between erosion and deposition by up to 89%, while the bed level could be incised by an additional 146%.

scholarly journals Future sediment dynamics in the Mekong Delta floodplains: Impacts of hydropower development, climate change and sea level rise

2015 ◽  
Vol 127 ◽  
pp. 22-33 ◽  
Author(s):  
Nguyen Van Manh ◽  
Nguyen Viet Dung ◽  
Nguyen Nghia Hung ◽  
Matti Kummu ◽  
Bruno Merz ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Mekong Delta ◽  
Sediment Dynamics ◽  
Hydropower Development ◽  
And Sea Level

Modelling climate change impacts on the flood pulse in the Lower Mekong floodplains

2010 ◽  
Vol 1 (1) ◽  
pp. 67-86 ◽  
Author(s):  
K. Västilä ◽  
M. Kummu ◽  
C. Sangmanee ◽  
S. Chinvanno
Keyword(s):  
Climate Change ◽  
Water Balance ◽  
Sea Level Rise ◽  
Sea Level ◽  
Mekong Delta ◽  
Flood Pulse ◽  
Water Levels ◽  
Infrastructure Development ◽  
Ecosystem Productivity ◽  
Basin Water

The flood pulse is a key element characterizing the hydrology of the Mekong River and driving the high ecosystem productivity in the Lower Mekong floodplains, both in the Cambodian lowlands and the Mekong Delta in Vietnam. This paper assesses the impacts of climate change, both in terms of changed basin water balance and sea level rise, on the Lower Mekong flood pulse. The impacts were simulated by a three-dimensional hydrodynamic model using the projected changes in sea level and the Mekong mainstream discharge under the influence of climate change as boundary conditions. The model simulations projected that average and maximum water levels and flood duration increase in 2010–2049. The most consistent and notable changes occurred in the average and dry hydrological years. Sea level rise had the greatest effects in the Mekong Delta, whereas the impacts of changed basin water balance were more notable in the upper areas of the Mekong floodplains. The projected impacts were mostly opposite to those resulting from regional water infrastructure development. Higher and longer flooding could cause damage to crops, infrastructure and floodplain vegetation, and decrease the fertile land area. On the other hand, it might boost ecosystem productivity and enhance dry season water availability.

scholarly journals Some methods on flood inudation mappings for Long An province under climate change and sea level rise

2013 ◽  
Vol 16 (1) ◽  
pp. 32-39
Author(s):  
Quan Hong Nguyen
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Mekong Delta ◽  
Flood Inundation ◽  
Gis Analysis ◽  
Adaptation Measures ◽  
Inundation Maps ◽  
Inundation Map ◽  
And Sea Level

Mapping flood inundation can be done by different methods, of which GIS analysis and flood modeling can be considered as the most popular ones. The modeling approach often requires more data but produce more detail results comparing to the GIS. Based on the assessment of current applied methods for building flood inundation map in the Mekong delta provinces in general and Long An in particular as well as based on some recent results of using GIS, 1 D ISIS model and 1-2D Mike Flood model applied in Long An province, the author show advantages as well as disadvantages of each methods and especially the results’ confidence. As the result, the author presents some challenges in mapping flood inundation maps under climate change and sea level rise. Integrating hydraulic construction (e.g. dyke, sluice, storage areas) and adaptation measures in the current and future in the analysis are typical challenges.

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