scholarly journals Sand mining in the Mekong Delta revisited - current scales of local sediment deficits

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Christian Jordan ◽  
Jan Tiede ◽  
Oliver Lojek ◽  
Jan Visscher ◽  
Heiko Apel ◽  
...  
Keyword(s):  
Coastal Erosion ◽  
Mekong Delta ◽  
Dam Construction ◽  
Sand Mining ◽  
Wet Season ◽  
Natural Sediment ◽  
High Magnitude ◽  
Cumulative Length ◽  
Extraction Volume ◽  
Sand Extraction

AbstractThe delta of the Mekong River in Vietnam has been heavily impacted by anthropogenic stresses in recent years, such as upstream dam construction and sand mining within the main and distributary channels, leading to riverbank and coastal erosion. Intensive bathymetric surveys, conducted within the Tien River branch during the dry and wet season 2018, reveal a high magnitude of sand mining activities. For the year 2018, an analysis of bathymetric maps and the local refilling processes leads to an estimated sand extraction volume of 4.64 $$\pm $$± 0.31 Mm$${}^{3}$$3/yr in the study area, which covered around 20 km. Reported statistics of sand mining for all of the Mekong’s channels within the delta, which have a cumulative length of several hundred kilometres, are 17.77 Mm$${}^{3}$$3/yr for this period. Results from this study highlight that these statistics are likely too conservative. It is also shown that natural sediment supplies from upper reaches of the Mekong are insufficient to compensate for the loss of extracted bed aggregates, illustrating the non-sustainable nature of the local sand mining practices.

scholarly journals The Morphological Measurement Variations of Periophthalmus chrysospilos along the Coastline in the Mekong Delta

2021 ◽  
Author(s):  
Le Trung Hieu ◽  
Dinh Minh Quang ◽  
Hua Van U ◽  
Nguyen Huu Duc Ton
Keyword(s):  
Morphological Variation ◽  
Body Height ◽  
Mekong Delta ◽  
Wet Season ◽  
Morphological Variations ◽  
Total Length ◽  
Fish Samples ◽  
Eye Diameter ◽  
And Gender ◽  
Study Sites

This study provided data on morphological variation in Periophthalmus chrysospilos. The study was carried out in four provinces from Tra Vinh to Soc Trang, Bac Lieu and Ca Mau. Fish samples were collected by hand-catching over 12 months from April 2020 to March 2021. Analysed results of a collection of 1,031 individuals (508 females and 523 males) showed that the total length (TL) and weight (W) of the female Periophthalmus chrysospilos were higher than that of the male, higher in the wet season than in the dry season and gradually increased from Tra Vinh to Ca Mau. Besides, the total length and weight of fish were also influenced by the interaction of season ´ site and gender ´ site. In addition, the morphological variation of this species such as eye diameter (ED), eye distance (DE), body height (BD), head length (HL) and taxonomic ratios such as HL/TL, BD/TL, ED/HL, DE/HL was gender, seasonal fluctuations and study sites. These morphological variations and ratios were also influenced by interactions season ´ site interactions. The findings contributed further information to fish identification and the ecological adaptation understanding of this species.

scholarly journals Seasonality of Mansonia titillans during dam construction, Biritiba-Mirim, São Paulo State, Brazil

2013 ◽  
Vol 13 (1) ◽  
pp. 70-73 ◽  
Author(s):  
Frederico Alves D'Avila ◽  
Almério de Castro Gomes
Keyword(s):  
Early Spring ◽  
Dry Season ◽  
Southeastern Brazil ◽  
Rank Test ◽  
Late Winter ◽  
Dam Construction ◽  
Wet Season ◽  
Paulo State ◽  
Significant Difference ◽  
Wilcoxon Rank Test

A two and a half year survey was conducted at a dam in southeastern Brazil. Shannon Traps were used for sampling. Kruskal-Wallis test showed little relation between rainfall and abundance. The data clearly show three abundance peaks, all of them in the end of the dry season, in consonance with the scarce literature existent. Although Kruskal-Wallis Test did not find a clear preference for the dry season, Pairwise Wilcoxon Rank Test revealed a significant difference between Fall and Spring samples. Ma. titillans population had a peak on late winter/early spring, close to the begin of wet season.

scholarly journals Erosi Pantai, Ekosistem Hutan Bakau dan Adaptasi Masyarakat Terhadap Bencana Kerusakan Pantai Di negara Tropis (Coastal Erosion, Mangrove Ecosystems and Community Adaptation to Coastal Disasters in Tropical Countries)

2017 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Aji Ali Akbar ◽  
Junun Sartohadi ◽  
Tjut Sugandawaty Djohan ◽  
Su Ritohardoyo
Keyword(s):  
Natural Resources ◽  
Human Behavior ◽  
Coastal Erosion ◽  
Mangrove Ecosystem ◽  
Sand Mining ◽  
The Public ◽  
Community Adaptation ◽  
Public Facilities ◽  
Mangrove Ecosystems ◽  
The Government

ABSTRAK Tulisan ini bertujuan untuk mengkaji terjadinya kerusakan lingkungan pantai di negara tropis dan sebagian negara subtropis akibat perilaku manusia. Perilaku manusia yang menyebabkan kerusakan lingkungan adalah memanfaatkan sumberdaya alam pesisir tanpa memperhatikan keberlanjutan sumber daya alam dan daya dukung lingkungannya. Kerusakan lingkungan pantai yang umum terjadi di negara tropis dan sebagian subtropis adalah erosi pantai dan degradasi ekosistem hutan bakau. Kerusakan lingkungan pantai ini akibat alih fungsi lahan menjadi jaringan jalan, permukiman, lahan pertanian/ perkebunan, pertambakan, dan pertambangan pasir. Kerusakan lingkungan pantai mempengaruhi kondisi sosial ekonomi masyarakat setempat seperti hilangnya badan jalan, permukiman, lahan pertanian, dan fasilitas umum akibat abrasi pantai. Upaya penanggulangan kerusakan lingkungan pantai sebagai bagian dari adaptasi manusia mempertahankan kehidupannya berupa pembangunan pemecah gelombang (breakwaters) dan rehabilitasi ekosistem hutan bakau. Upaya penanggulangan bencana tersebut tentunya membutuhkan biaya yang besar dan waktu lama daripada upaya pencegahan. Oleh karena itu, perubahan pola pikir baik pemerintah dan masyarakat dalam memanfaatkan, mengelola dan melestarikan sumber daya alam perlu ditingkatkan melalui perbaikan informasi, ilmu pengetahuan, dan strategi perencanaan yang holistik.Kata kunci: erosi pantai, kerusakan ekosistem hutan bakau, alih fungsi lahan, pemecah gelombang, rehabilitasiABSTRACTThis paper aims to assess the coastal degradation in tropical and subtropical countries in part due to human behavior. Human behavior is causing coastal degradation is to utilize natural resources without regard to the sustainability of coastal natural resources and the carrying capacity of the environment. Degradation of coastal common in most tropical and subtropical countries are coastal erosion and degradation of mangrove ecosystems. This coastal degradation as a result of land conversion into roads, settlements, agricultural/ plantation, aquaculture, and sand mining. Coastal degradation affects the socio-economic conditions of local communities such as loss roads, settlements, land and public facilities as a result of coastal erosion. Efforts to cope to the coastal degradation as part of human adaptation to sustain life in the form of construction of breakwaters and rehabilitation of mangrove ecosystems. The disaster relief certainly require a plenty of cost and time than prevention. Therefore, changes in the mindset of both the government and the public in using, managing and conserving natural resources should be increased through improvement of information, knowledge, and holistic planning strategies.Keywords: coastal erosion, mangrove ecosystem degradation, land use, breakwaters, rehabilitationCara sitasi: Akbar,A.,A., Sartohadi., J., Djohan, T.S. and Ritohardoyo, S. (2017). Erosi Pantai, Ekosistem Hutan Bakau dan Adaptasi Masyarakat Terhadap Bencana Kerusakan Pantai Di negara Tropis. Jurnal Ilmu Lingkungan,15(1),1-10, doi:10.14710/jil.15.1.1-10

scholarly journals MONITORING EROSION AND ACCRETION SITUATION IN THE COASTAL ZONE AT KIEN GIANG PROVINCE

2018 ◽  
Vol XLII-3/W4 ◽  
pp. 197-203
Author(s):  
N. T. H. Diep ◽  
N. T. Loi ◽  
N. T. Can
Keyword(s):  
Land Use ◽  
Coastal Area ◽  
Coastal Erosion ◽  
Landsat Imagery ◽  
Mekong Delta ◽  
The West ◽  
Shoreline Changes ◽  
Water Index ◽  
Normalized Difference Water Index ◽  
Erosion And Accretion

<p><strong>Abstract.</strong> Kien Giang is one of the coastal provinces in the Mekong Delta which is facing the problem of coastal erosion to affect people’s life in the coastal area. This project aims to monitor shoreline and to assess landslide and accretion situation in the period from 1975 to 2015 in the coastal area of Kien Giang province. The study applied Normalized Difference Water Index (MNWI) method and water level extraction using LANDSAT imagery from 1975 to 2015 for highlight the shoreline. Thus, analysis was identified erosion and accretion areas based on shoreline changes and land use influenced by landslides and deposition. The results show to create shoreline changes from 1997 to 2015 in the coastal area of Kien Giang province. A landslide occurred in the west from Nguyen Viet Khai commune to Thuan Hoa commune and Nam Yen commune to Vinh Hoa Hiep commune, Rach Gia city, Kien Giang province. An accretion situation was determined in the areas from Thuan Hoa commune, An Minh district to Nam Thai commune, An Bien district, Kien Giang province, Rach Gia sea encroachment at Rach Gia town and Ha Tien encroachment area at Ha Tien town, Kien Giang province. In general, the coastal area of Kien Giang province has a predominant tendency of accretion, however, the occurrence of erosion and accretion are happened interlacing in the coastal area at Kien Giang province.</p>

scholarly journals Groundwater Quality Assessment Using Fuzzy-AHP in An Giang Province of Vietnam

Geosciences ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 330 ◽  
Author(s):  
Minh ◽  
Avtar ◽  
Kumar ◽  
Tran ◽  
Ty ◽  
...  
Keyword(s):  
Groundwater Quality ◽  
River Discharge ◽  
Suspended Solids ◽  
Fuzzy Ahp ◽  
Monsoon Season ◽  
Mekong Delta ◽  
Sediment Concentration ◽  
Sufficient Evidence ◽  
Wet Season ◽  
Shallow Wells

Along with rapid population growth in Vietnam, there is an increasing dependence on groundwater for various activities. An Giang province is known to be one of the agricultural intensification areas of The Vietnamese Mekong Delta (VMD). This study aimed to evaluate the spatiotemporal variation of groundwater quality for a period of ten years from 2009 to 2018 in An Giang. The weighted groundwater quality index (GWQI) was developed based on the fuzzy analytic hierarchy process (Fuzzy-AHP) for assigning weighted parameters. The results show that that shallow wells in the Northeast and Southeast regions of An Giang were mostly categorized under “bad water” quality with high arsenic (As) concentration over the years partly due to huge amounts of sediment deposition in monsoon season. Overall, the reason for the poor groundwater quality in An Giang was the combined effect of both natural and human activities. On the other hand, we detected high values of GWQI links with high As concentration in areas where people extract more groundwater for irrigation. Temporal variation of GWQI suggested that groundwater quality at eight wells has improved from 2009 to 2018 in the wet season as compared to the dry season. The reason behind the improvement of groundwater quality during wet season was the decrease in river discharge, which causes less deposition of suspended solids near the flood plains. Moreover, the filling of unused wells can reduce the movement of pollutants from unused wells to groundwater aquifers. Although there was not sufficient evidence to show the relationship between As and sediment concentration, the temporal reduction trend in river discharge and suspended solids was detected in An Giang. The understanding of groundwater quality can help policymakers protect and manage limited water resources in the long-term.

scholarly journals The Effect of a Dam Construction on Subtidal Nematode Communities in the Ba Lai Estuary, Vietnam

Diversity ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 137 ◽  
Author(s):  
Nguyen Thi My Yen ◽  
Ann Vanreusel ◽  
Lidia Lins ◽  
Tran Thanh Thai ◽  
Tania Nara Bezerra ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Suspended Solids ◽  
Metal Accumulation ◽  
Mekong Delta ◽  
Oxygen Depletion ◽  
Heavy Metal Accumulation ◽  
Organic Load ◽  
Dam Construction ◽  
Nematode Communities ◽  
Genus Richness

Nematode communities and relevant environmental variables were investigated to assess how the presence of a dam affects the Ba Lai estuary benthic ecosystem, in comparison to the adjacent dam-free estuary Ham Luong. Both estuaries are part of the Mekong delta system in Vietnam. This study has shown that the dam’s construction had an effect on the biochemical components of the Ba Lai estuary, as observed by the local increase in total suspended solids and heavy metal concentrations (Hg and Pb) and by a significant oxygen depletion compared to the natural river of Ham Luong. The nematode communities were also different between the two estuaries in terms of density, genus richness, Shannon–Wiener diversity, and dominant genera. The Ba Lai estuary exhibited lower nematode densities but a higher diversity, while the genus composition only slightly differed between estuaries. The results indicate that the present nematode communities may be well adapted to the natural organic load, to the heavy metal accumulation and to the oxygen stress in both estuaries, but the dam presence may potentially continue to drive the Ba Lai’s ecosystem to its tipping point.

scholarly journals The Unsustainable Use of Sand: Reporting on a Global Problem

2021 ◽  
Vol 13 (6) ◽  
pp. 3356
Author(s):  
Walter Leal Filho ◽  
Julian Hunt ◽  
Alexandros Lingos ◽  
Johannes Platje ◽  
Lara Werncke Vieira ◽  
...  
Keyword(s):  
Climate Change ◽  
Law Enforcement ◽  
Coastal Areas ◽  
Tourism Industry ◽  
Building Construction ◽  
Water Filtration ◽  
Mining Activities ◽  
Sand Mining ◽  
Environmental Damages ◽  
Sand Extraction

Sand is considered one of the most consumed natural resource, being essential to many industries, including building construction, electronics, plastics, and water filtration. This paper assesses the environmental impact of sand extraction and the problems associated with its illegal exploitation. The analysis indicates that extracting sand at a greater rate than that at which it is naturally replenished has adverse consequences for fauna and flora. Further, illicit mining activities compound environmental damages and result in conflict, the loss of taxes/royalties, illegal work, and losses in the tourism industry. As sea-level rise associated with climate change threatens coastal areas, sand in coastal areas will play an increasingly greater role in determining the amount of damage from floods and erosion. The present analysis points to the need for swift action to regulate sand mining, monitoring, law enforcement, and international cooperation.

scholarly journals Lagoon degradation and management in Yanuca Channel on the Coral Coast of Fiji

2006 ◽  
Vol 24 (1) ◽  
pp. 1 ◽  
Author(s):  
James P Terry ◽  
Priya Kisun ◽  
Aminiasi Qareqare ◽  
Jyotishma Rajan
Keyword(s):  
Marine Protected Areas ◽  
Environmental Conditions ◽  
Coastal Erosion ◽  
Agricultural Practices ◽  
Sand Mining ◽  
Drainage Pattern ◽  
Management Options ◽  
Traditional Management ◽  
South West ◽  
Marine Lagoon

Yanuca Channel is a narrow marine lagoon separating a low limestone island in Cuvu Bay from the south west Viti Levu mainland in Fiji, known as the ?Coral Coast?. Historical air photographs show significant changes in the drainage configuration of the lagoon and local Fijian landowners give accounts of degrading environmental conditions in the lagoon due to sediment infilling. This investigation found several processes were responsible for the aggradation. Large quantities of terrigenous sediments are discharged by streamwaters into the lagoon, as a consequence of the removal of estuarine mangroves and agricultural practices such as burning and grazing in adjacent catchments. A previous outlet into the bay became blocked in the 1980s after inappropriate sand mining and vegetation clearance caused accelerated coastal erosion. The altered lagoon drainage pattern has led to lagoon eutrophication and aggradation. Developed on the island is a large international resort complex; the resort causeway constructed across the lagoon to the island has a significant dam effect, impeding the flow of currents and preventing the periodic scouring of sand from the lagoon floor. Several modern and traditional management options have recently been implemented to improve lagoon conditions, through partnerships between NGOs, traditional landowners and the resort management. These include riparian reforestation and the establishment of marine protected areas to conserve coral reefs.

scholarly journals Downstream State and Water Security in the Mekong Region: A Case of Cambodia between Too Much and Too Little Water

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 802
Author(s):  
Mak Sithirith
Keyword(s):  
Water Management ◽  
Water Resource ◽  
Water Resource Management ◽  
Irrigation System ◽  
Irrigation Management ◽  
Mekong Delta ◽  
High Water ◽  
Policy Implications ◽  
Wet Season ◽  
Mekong Region

Cambodia has too much water during the wet season, and too little water remains in the dry season, which drives a relentless cycle of floods and droughts. These extremes destroy crops, properties, infrastructure, and lives and contribute to poverty. Thus, water management is key to the development of Cambodia. This article seeks to answer the question why Cambodia is vulnerable to floods and drought and how these conditions undermine the country’s development. It also examines what can be done to improve the country’s water resource management and the livelihoods of its population. The article examines water resource availability in Cambodia, its management regimes, and the policy implications in answering these research questions. The article looks at three case studies: first, the Stung Chreybak irrigation scheme in the Tonle Sap region; second, the Lower Sesan 2 Dam (LS2) in the Sesan, Srepok, and Sekong (3S) basin in Cambodia; and third, the transboundary water management in the Mekong Delta. It concludes that water management has been equated to irrigation management. However, the irrigation system in Cambodia has been inadequate to cope with the tremendous volume of water. Furthermore, water management has been complicated by the hydropower dams in the Upper Mekong region and the rubber dams in Vietnam’s Mekong Delta. These contribute to high water insecurity in Cambodia.

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