The past and future dynamics of salt intrusion in the Mekong Delta

2021 ◽  
Author(s):  
Sepehr Eslami ◽  
Maarten van der Vegt ◽  
Philip Minderhoud ◽  
Nam Nguyen Trung ◽  
Jannis Hoch ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Policy Development ◽  
Environmental Changes ◽  
Mekong Delta ◽  
Environmental Drivers ◽  
Salt Intrusion ◽  
Rapid Urbanization ◽  
The World ◽  
Anthropogenic Drivers

<p>In the context of global rising temperatures, rapid urbanization and excessive demand for natural resources (e.g., freshwater and sand) stress the livelihood of the world deltas. Sea Level Rise, land subsidence, discharge anomalies, floods, drought, and salt intrusion are common challenges facing these ecologically essential and economically crucial coastal landscapes. Climate change projections in deltas regularly isolate climate-driven stressors and disregard anthropogenic environmental drivers. This often leads to insufficient socio-political drive at times when the short window of opportunity to save the world’s largest deltas is closing. Here, by integrating both climatic and anthropogenic drivers of exposure and vulnerability, we project salt intrusion within the Mekong mega-Delta for the next three decades. Leveraging modern numerical codes and computation capacity, by applying a high-resolution 3D model we capture the 3D dynamics of saline water intrusion, and by covering the entire delta (from 400 km upstream to 70 km offshore) we eliminate/minimize the boundary effects at the areas of interest. We differentiate the relative effects of various drivers and demonstrate that while sea level rise can increase areas affected by salinity by 5-19%, anthropogenic drivers such as extraction-induced subsidence and riverbed level incisions due to sediment starvation can further amplify that by additional 10-27%. The results are crucial input for climate adaptation policy development in the Mekong Delta and provides a blueprint for systemic assessment of environmental changes and developing environmental pathways at scale of a delta.</p>

scholarly journals Projections of salt intrusion in a mega-delta under climatic and anthropogenic stressors

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Sepehr Eslami ◽  
Piet Hoekstra ◽  
Philip S. J. Minderhoud ◽  
Nam Nguyen Trung ◽  
Jannis M. Hoch ◽  
...  
Keyword(s):  
Policy Development ◽  
Environmental Changes ◽  
Numerical Models ◽  
Mekong Delta ◽  
Environmental Stressors ◽  
Groundwater Extraction ◽  
Climate Change Projections ◽  
Salt Intrusion ◽  
Rapid Urbanization ◽  
Anthropogenic Processes

AbstractRising temperatures, rapid urbanization and soaring demand for natural resources threaten deltas worldwide and make them vulnerable to rising seas, subsidence, droughts, floods, and salt intrusion. However, climate change projections in deltas often address climate-driven stressors in isolation and disregard parallel anthropogenic processes, leading to insufficient socio-political drive. Here, using a combination of process-based numerical models that integrate both climatic and anthropogenic environmental stressors, we project salt intrusion within the Mekong mega-Delta, in the next three decades. We assess the relative effects of various drivers and show that anthropogenic forces such as groundwater extraction-induced subsidence and riverbed level incisions due to sediment starvation can increase the salinity-affected areas by 10–27% compared to the present-day situation, while future sea level rise adds another 6–19% increase. These projections provide crucial input for adaptation policy development in the Mekong Delta and the methodology inspires future systemic studies of environmental changes in other deltas.

The existential crisis of the Mekong delta: Impact of accelerating land subsidence

2020 ◽  
Author(s):  
Philip S.J. Minderhoud ◽  
Gilles Erkens ◽  
Hans Middelkoop ◽  
Esther Stouthamer
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Land Subsidence ◽  
Mekong Delta ◽  
Relative Sea Level ◽  
Natural Processes ◽  
Existential Crisis ◽  
The World ◽  
Relative Sea Level Rise ◽  
Imminent Threat

<p>Land subsidence is one of the slowest, natural processes faced by deltas throughout the world, yet it acts as an important catalyst which exacerbates all other threats associated with relative sea-level rise, such as increased flood vulnerability and salinization. This presentation summarizes the results of five years of research on land subsidence in the Mekong delta and highlights the major advances in approaches and insights gained in subsidence processes and rates of an entire mega-delta system.</p><p>The Mekong delta is heading towards an existential crisis as land subsidence rates are rapidly accelerating over the past decades up to ~5 cm/yr. As sediment starvation in the Mekong river greatly reduces the adaptive capacity to counterbalance subsidence, this results in wide-spread loss of delta elevation. With the Mekong delta having an average elevation of less than 1 meter above local mean sea level, these elevated rates of relative sea-level rise pose an imminent threat of land loss and permanent submersion in the coming decades.</p><p>Like in many densely populated and rapidly developing coastal-deltaic areas around the world, the main anthropogenic driver that causes accelerated subsidence is the overexploitation of groundwater. A range of future delta elevation projections, considering sea-level rise and simulated groundwater extraction-induced subsidence following extraction pathways, show the dire situation of the delta in spatial-temporal explicit maps of future elevation relative to local sea level.</p><p>Adequate (ground)water management aimed at strongly reducing current extractions is key in mitigating accelerating sinking rates and crucial to ensure the survival of the Mekong delta. The window of opportunity to act is swiftly closing as the delta is rapidly running out of elevation, and therefore time.</p>

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>

THE DYNAMIC OF ADAPTIVE SHELTER: SEBUAH WADAH ADAPTIF-DINAMIS DI KAMPUNG NELAYAN, KAMAL MUARA

2021 ◽  
Vol 3 (1) ◽  
pp. 1127
Author(s):  
Fransisca Handayani ◽  
Alvin Hadiwono
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Martin Heidegger ◽  
Sea Level ◽  
Adaptive Dynamic ◽  
Community Activities ◽  
World Today ◽  
Christopher Alexander ◽  
The World ◽  
Natural Characteristics

"Dwelling" basically means living in a place. However, Dwelling itself has a broader meaning when we understand how humans decided to inhabit. In the book The Nature of Order, Christopher Alexander says "Dwelling is Living-Structure" which means to live is a life participating in a living-structure. This quote directly describes a relationship between nature and humans in the process of living. Seeing the conditions that exist in the world today, there are many aspects that can affect the way humans will live in the future. One of the problems that humans have to face is climate change which causes sea level rise. Realizing that humans must face these events and know that in reality, humans cannot be separated from their natural surroundings, "The Dynamic of Adaptive Shelter" was designed with the aim of wanting to unite aspects of habitation (especially nature and humans) as well as provide solutions for buildings that are adaptive to sea level rise. Located in Kamal Muara, North Jakarta, this project begins by studying the selected site, community activities, the shape of the buildings around the site, as well as the natural characteristics around the site, as a method that refers to a quote from Martin Heidegger's book about "the thing It-self". Referring to the results of the selected site, this project is complemented with programs that are suitable for the activities of the residents of the area and have been developed with systems which can adapt to the issue of sea level rise. Keywords:  Adaptive-Dynamic; Coastal; Dwelling; Fishermen ; Sea Level Rise Abstrak“Dwelling” atau Berhuni pada dasarnya memiliki arti hidup pada suatu tempat. Namun Dwelling sendiri memiliki arti yang lebih luas saat kita memahami awal mula manusia memutuskan untuk berhuni. Dalam buku The Nature of Order Christohper Alexander mengatakan “Dwelling is Living- Structure” yang berarti berhuni adalah hidup berpartisipasi dalam Struktur-kehidupan (Living- structure). Kutipan tersebut secara langsung menggambarkan sebuah keterkaitan antara alam dan manusia dalam menuju proses berhuni. Melihat kondisi yang ada didunia saat ini banyak aspek yang dapat mempengaruhi cara manusia berhuni dimasa depan. Salah satu permasalahan yang harus dihadapi manusia adalah perubahan iklim yang menyebabkan kenaikan permukaan air laut. Menyadari bahwa manusia harus menghadapi peristiwa tersebut dan mengetahuni bahwa pada dasarnya dalam proses berhuni manusia tidak terlepas dari alam sekitarnya, “Wadah Adaptif- Dinamis” dirancang dengan tujuan ingin mempersatukan aspek-aspek berhuni (khususnya alam dan manusia) dan juga memberikan solusi akan bangunan yang adaptif akan kenaikan permukaan air laut. Berlokasi di Kamal Muara, Jakarta Utara proyek ini diawali dengan mempelajari site terpilih, aktivitas masyarakat, bentuk bangunan sekitar tapak, dan juga karakteristik alam sekitar tapak, sebagaimana metode yang mengacu pada kutipan buku Martin Heidegger tentang “the thing It-self”. Mengacu pada hasil analisis tapak terpilih, proyek ini dilengkapi dengan program-program yang sesuai dengan aktifitas penduduk daerahnya dan telah dikembangkan dengan sistem-sistem yang mana dapat beradaptasi dengan kondisi alam sekitar dan menjawa isu akan kenaikan permukaan air laut.

scholarly journals Holocene sea level and climate interactions on wet dune slack evolution in SW Portugal: A model for future scenarios?

The Holocene ◽  
2018 ◽  
Vol 29 (1) ◽  
pp. 26-44 ◽  
Author(s):  
Manel Leira ◽  
Maria C Freitas ◽  
Tania Ferreira ◽  
Anabela Cruces ◽  
Simon Connor ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Environmental Changes ◽  
Sediment Accumulation ◽  
High Energy ◽  
Sediment Supply ◽  
Dune Slack ◽  
Ecological Stability ◽  
The Holocene ◽  
Climate Interactions

We examine the Holocene environmental changes in a wet dune slack of the Portuguese coast, Poço do Barbarroxa de Baixo. Lithology, organic matter, biological proxies and high-resolution chronology provide estimations of sediment accumulation rates and changes in environmental conditions in relation to sea-level change and climate variability during the Holocene. Results show that the wet dune slack was formed 7.5 cal. ka BP, contemporaneous with the last stages of the rapid sea-level rise. This depositional environment formed under frequent freshwater flooding and water ponding that allowed the development and post-mortem accumulation of abundant plant remains. The wetland evolved into mostly palustrine conditions over the next 2000 years, until a phase of stabilization in relative sea-level rise, when sedimentation rates slowed down to 0.04 mm yr−1, between 5.3 and 2.5 cal. ka BP. Later, about 0.8 cal. ka BP, high-energy events, likely due to enhanced storminess and more frequent onshore winds, caused the collapse of the foredune above the wetlands’ seaward margin. The delicate balance between hydrology (controlled by sea-level rise and climate change), sediment supply and storminess modulates the habitat’s resilience and ecological stability. This underpins the relevance of integrating past records in coastal wet dune slacks management in a scenario of constant adaptation processes.

scholarly journals INFLUENCE OF OCEAN TIDE AND SEA-LEVEL RISE ON FLOOD IN URBAN AREAS OF MEKONG DELTA

2013 ◽  
Vol 69 (2) ◽  
pp. I_988-I_993
Author(s):  
Hiroshi TAKAGI ◽  
Tran Van TY ◽  
Nguyen Danh THAO ◽  
Miguel ESTEBAN ◽  
Yuto TAKAHASHI
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Urban Areas ◽  
Mekong Delta ◽  
Ocean Tide ◽  
And Sea Level

scholarly journals Challenges in Chennai City to Cope with Changing Climate

2021 ◽  
Vol 3 (1) ◽  
pp. 33-43
Author(s):  
Anushiya Jeganathan ◽  
Ramachandran Andimuthu ◽  
Palanivelu Kandasamy
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Sea Level Rise ◽  
Sea Level ◽  
Coastal Hazards ◽  
Risk Level ◽  
Rapid Urbanization ◽  
Changing Climate ◽  
Green Cover ◽  
Chennai City

Cities are dynamic systems resulting from the complex interaction of various socio-ecological and environmental developments. Climate change disproportionately affects cities mostly located in climate-sensitive areas; thus, these urban systems are the most critical in modern societies under changing climate scenarios, uncertain disruptions, and urban inhabitants' daily lives. It is essential to analyze the challenges in the metropolitan area through the lens of climate change. The present work analyses the challenges in Chennai, a coastal city in India and one of the chief industrial growth canters in Indian and South Asian region. The challenges are analyzed through the city’s system analysis via land use, green cover, population, and coastal hazards. Land use and green cover changes are studied through satellite images using ArcGIS and assessing coastal risks due to sea-level rise through GIS-based inundation model. There are drastic changes in land-use patterns; the green cover had reduced much, including agricultural and forest cover due to rapid urbanization. The land use has changed to 59.6% of the reduction in agriculture land, nearly 40% reduction in forest land, and 47% of the wetland over time. The observed mean sea level trend for Chennai is + 0.55 mm/year from 1916 to 2015 and the area of 21.75 sq. km is under the threat of inundation to 0.5m sea-level rise. The population growth, drastic changes in land use pattern, green cover reduction, and inundation due to sea-level rise increase the city's risks to climate change. There is a need to ensure that future land-use developments do not worsen the current climate risk level, either through influencing the hazards themselves or affecting the urban system's future vulnerability and adaptive capacity. The study also urges the zone level adaptation strategies to ensure the resilience of the city.

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