scholarly journals New systemically measured sand mining budget for the Mekong Delta reveals rising trends and significant volume underestimations

2021 ◽  
Author(s):  
Charles Gruel ◽  
Edward Park ◽  
Loc Ho ◽  
Sameh Kantoush ◽  
Lian Feng ◽  
...  
Keyword(s):  
Mekong Delta ◽  
Annual Rate ◽  
Mining Activities ◽  
Sand Mining ◽  
Short Channel ◽  
Salt Intrusion ◽  
Continuous Increase ◽  
Physically Based ◽  
Radar Imagery ◽  
Integrated Study

The river beds of the Mekong Delta are some of the most intensively sand mined places in the world, however sand mining budgets are limited to rough and indirect estimates. Here, we provide a systematic, semi-physically based estimation of the Mekong Delta’s sand mining budget. We provide a quantified budget that overcomes limitations resulting from previous reliance on officially declared statistics and bathymetric surveys of short channel reaches. We apply Sentinel-1 radar imagery to monitor the distribution of sand mining activities using boat metrics-driven mining intensity maps correlated with a field-based bathymetry difference map derived from two extensive bathymetric surveys of ~100 km reaches in the Tiền River conducted in 2014 and 2017 that cover ~15% of the Mekong Delta. We then extrapolate the Tiền River findings to the broader Vietnamese Mekong Delta from 2015 to 2020 and measure a continuous increase of the extraction budget by ~25% between 2015 (38 Mm3/yr) and 2020 (47 Mm3/yr). We estimate a total sand mining budget of 254 Mm3 during the 6-year study period with an average annual rate of ~42 Mm3. Our semi-physically based annual rate differs from both official declarations provided and estimates from previous studies implying that a substantial portion of sand mining budget remains unaccounted for. Riverbed sand mining remains key threat to the Mekong Delta as it exacerbates or contributes to a multitude of other threats including dam construction effects on sedimentation, ongoing subsidence, sea level rise and recurring salt intrusion. This integrated study offers a new method that is readily implementable elsewhere to allow for extensive monitoring and quantification of sand mining activities that are vital for assessing future projections on environmental impacts.

Soil Moisture Retrievals in Aeolian Sand Mining Areas Using Temporal, Single-Polarization, High-Resolution SAR

Frequenz ◽  
2018 ◽  
Vol 72 (11-12) ◽  
pp. 547-560
Author(s):  
Wei MA ◽  
Chao MA
Keyword(s):  
Soil Moisture ◽  
High Intensity ◽  
Surface Soil ◽  
Absolute Error ◽  
Mining Activities ◽  
Approximation Model ◽  
Sand Mining ◽  
Surface Soil Moisture ◽  
Aeolian Sand ◽  
Sampling Points

Abstract Changes in the soil moisture are a key factor in the deterioration of the ecological environment caused by mining geological disasters. In this study, which presents a case study of the arid and semi-arid aeolian sand mining area along the Inner Mongolia-Shaanxi Province boundary, a method for retrieving the soil moisture based on RADARSAT-2 SAR scattering data and Terra MODIS surface reflectance data was proposed. The retrieval of RADARSAT-2 mainly used the Alpha approximation model based on the change detection technique, a model proposed by Balenzano et al., which can effectively decouple the impact of surface vegetation and roughness on radar backscattering coefficient, when the volume scattering is not dominant. Using 12 periods of RADARSAT-2 HH polarization data in conjunction with the Alpha approximation model, a matrix equation was constructed, which contains 11 equations and 12 unknowns. To solve this underdetermined system, a bounded linear least-squares optimization was adopted. Once the unknowns were determined, the relative dielectric constant could be analytically derived and then the soil moisture could be estimated by using the dielectric mixing model and compared with the MODIS retrieval results based on the spatial feature method. Finally, the DInSAR results of RADARSAT-2 were used to investigate the effects of high-intensity underground mining activities on the surface soil moisture. The study found that the RADARSAT-2 soil moisture estimates demonstrated good consistency with the MODIS retrieval results. Among four comparison groups, the maximum correlation coefficient was 0.599, and the highest proportion of sampling points for which the absolute error was less than 3 % was 55.6 %. The absolute error of all of the sampling points did not exceed 10 %, which demonstrates the reliability of the RADARSAT-2 retrieval results. A comparison among the 72 soil moisture values from six mining subsidence areas and corresponding non-subsidence areas in the study area in 2012 showed that 38 soil moisture values from the non-subsidence areas were higher than those from the subsidence areas. These values accounted for 53 % of the total, indicating that high-intensity mining activities have a certain negative impact on the surface soil moisture, although this impact is slightly insignificant.

scholarly journals Salt intrusion in multi-channel estuaries: a case study in the Mekong Delta, Vietnam

2006 ◽  
Vol 10 (5) ◽  
pp. 743-754 ◽  
Author(s):  
A. D. Nguyen ◽  
H. H. Savenije
Keyword(s):  
River Discharge ◽  
Single Channel ◽  
Mekong Delta ◽  
Salt Intrusion ◽  
Predictive Equations ◽  
Alluvial Estuaries ◽  
Tidal Characteristics ◽  
Mixing Behaviour ◽  
Sloping Bottom

Abstract. There is a well-tested theory for the computation of salt intrusion in alluvial estuaries that is fully analytical and predictive. The theory uses analytical equations to predict the mixing behaviour of the estuary based on measurable quantities, such as channel topography, river discharge and tidal characteristics. It applies to single-channel topographies and estuaries that demonstrate moderate tidal damping. The Mekong delta is a multi-channel estuary where the tide is damped due to a relatively strong river discharge (in the order of 2000 m3/s), even during the dry season. As a result the Mekong is a strongly riverine estuary. This paper aims to test if the theory can be applied to such a riverine multi-channel estuary, and to see if possible adjustments or generalisations need to be made. The paper presents salt intrusion measurements that were done by moving boat in 2005, to which the salt intrusion model was calibrated. The theory has been expanded to cater for tidal damping. Subsequently the model has been validated with observations made at fixed locations over the years 1998 and 1999. Finally it has been tested whether the Mekong calibration fits the overall predictive equations derived in other estuaries. The test has been successful and led to a slight adjustment of the predictive equation to cater for estuaries that experience a sloping bottom.

Ac and Dc Characterization and Spice Modeling of Short Channel Polysilicon Tfts

1996 ◽  
Vol 424 ◽  
Author(s):  
M. D. Jacunski ◽  
M. S. Shur ◽  
T. Ytterdal ◽  
A. A. Owusu ◽  
M. Hack
Keyword(s):  
Frequency Dispersion ◽  
Channel Length ◽  
Short Channel ◽  
Spice Model ◽  
Dc Characteristics ◽  
Physically Based ◽  
In Series ◽  
Drain Bias ◽  
Long Channel ◽  
Good Agreement

AbstractWe present an analytical SPICE model for the AC and DC characteristics of n and p channel polysilicon TFTs which scales fully with channel length and width in all regimes of operation (leakage, subthreshold, above threshold, and kink) and accounts for the frequency dispersion of the capacitance. Once physically based parameters have been extracted from long channel TFTs, which include the gate length and drain bias dependencies of the device parameters, our model accurately reproduces short channel device characteristics. The AC model includes the input channel resistance in series with the gate oxide capacitance. As a result, our model is able to fit the frequency dispersion of the device capacitances. The model has been implemented in the AIM-Spice simulator and good agreement is observed between measured and modeled results for gate lengths down to 4 gim.

Combined Impacts of Sand Mining Activities: The Nandu River Downstream Segment

2013 ◽  
Vol 671-674 ◽  
pp. 3134-3137 ◽  
Author(s):  
Shu Wei Jiang ◽  
Abuduhelili Haibier ◽  
Yong Xin Wu
Keyword(s):  
Water Environment ◽  
Aquatic Organisms ◽  
Field Investigation ◽  
Hydrodynamic Characteristics ◽  
Social Stability ◽  
Mining Activities ◽  
Sand Mining ◽  
Natural Evolution ◽  
River Sand ◽  
Downstream Section

With the accelerated pace of urban construction in Hainan province, demand for building sand increased rapidly, river sand prices soared. This led to the illegal and unauthorized sand mining continue to emerge at Nandu River downstream segment. The current sand mining situation of Nandu River downstream section was expounded. The various impacts of sand mining activities on river regime, flood safety, hydrodynamic characteristics of the river, development of delta and water environment have been studied according to measured data and results of field investigation. It is shown that sand mining activities undermines the natural evolution of the river regime; affects the habitat of fish and other aquatic organisms. Water level drops, water velocity decreases, and the Nandu Rive delta coastline retrogrades due to sand extraction. Besides, sand mining has an obvious adverse impact on infrastructures, waterway safety and social stability.

scholarly journals APPLICATION OF TECHNOLOGY AS A SOCIAL ENGINEERING EFFORT ON THE IRON SAND MINING COMMUNITY AT THE SOUTH COAST OF WEST JAVA

2018 ◽  
Vol 3 (02) ◽  
pp. 133
Author(s):  
Desi Yunita
Keyword(s):  
Cultural Change ◽  
Economic Condition ◽  
Social Engineering ◽  
Mining Activities ◽  
Sand Mining ◽  
Economic Changes ◽  
Mining Community ◽  
Change Of Perspective ◽  
Engineering Effort ◽  
Livelihood System

This research aim to determine the extent of mining activities have an impact on the change to society. A series of research conducted show that mining activities undertaken by the community has prompted a change in the structure, culture, and economy. The three elements that change is a direct impact of the iron sand mining. Wherein the iron sand mining activities cause the change in interaction pattern, community perspective, and also rise the new social groups. Cultural change can be observed from the changes of the community livelihood system that also affect to the community relation pattern. Whereas economic changes are indicated by the sift of livelihood, but it doesn’t significantly change the economic condition. The application of technology has successfully encourage a change of perspective, attitude, mindset, increase incomes in the economy, and encourage environmentally friedly mining practices. 

scholarly journals PENERAPAN K3 BAGI PENAMBANG PASIR DI ALIRAN SUNGAI NOELMINA KECAMATAN BATUPUTIH KABUPATEN TIMOR TENGAH SELATAN PROVINSI NTT

2020 ◽  
Vol 4 (1) ◽  
pp. 87-97
Author(s):  
Yusuf Rumbino ◽  
Noni Banunaek
Keyword(s):  
Work Environment ◽  
Community Education ◽  
Health And Safety ◽  
First Aid ◽  
Warning Signs ◽  
Protective Equipment ◽  
Mining Activities ◽  
Sand Mining ◽  
Human Labor ◽  
A Company

CV. Talenalain is a company that mines sand without using excavators, but uses human labor and has a workforce of 25 people aged between 15 and 60 years. The Community Education Method is applied to increase workers' awareness of using PPE (personal protective equipment), understanding work hazards and diseases arising from sand mining activities. The material presented by the executive was about the benefits of PPE, handling minor incidental accidents, technical identification of hazards and diseases in the work environment. Apart from that, 25 sets of PPE equipment (helmets, gloves, rubber shoes, nose cover) were provided, 1 set of first aid kit, 1 set of warning signs, and several books on OHS Mining. The results of the activities of the implementation of Occupational Health and Safety (OHS) in the company can increase mining production by 20%, discipline to use PPE increased by 80%, increase in income of workers increased by 30%. This shows that the improvement of the OHS system can increase overall company productivity

scholarly journals Dynamics of salt intrusion in the Mekong Delta: results of field observations and integrated coastal–inland modelling

2021 ◽  
Vol 9 (4) ◽  
pp. 953-976
Author(s):  
Sepehr Eslami ◽  
Piet Hoekstra ◽  
Herman W. J. Kernkamp ◽  
Nam Nguyen Trung ◽  
Dung Do Duc ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Saline Water ◽  
Water System ◽  
Mekong Delta ◽  
Hydrological Regime ◽  
Salt Transport ◽  
Mixed System ◽  
Estuarine System ◽  
Salt Intrusion ◽  
Numerical Domain

Abstract. On the list of challenges facing the world largest deltas, increased saline water intrusion (SWI) in the surface water system and its role in jeopardizing freshwater supply are often ranked very high. Yet, detailed process-based studies of SWI at the whole delta scale are limited, and the trends are regularly associated with global sea level rise. Here, using field measurements and a sophisticated 3D model that integrates the riverine, rural, estuarine, and coastal dynamics within one numerical domain, we study SWI at the scale of the Mekong Delta in extensive detail. While many studies downscale the SWI problem to a topic within an estuary, we show that the physical processes on the continental shelf, such as monsoon-driven ocean surge, directly influence salinity dynamics within the delta. Typical values of 20–40 cm surge over the continental shelf contribute to up to 10 km of further SWI. The delta's estuarine system is also more sensitive than many other systems to variations of river discharge. Furthermore, spring–neap variability plays a key role in SWI in the delta. The estuarine variability from a stratified to a mixed system between neap and spring tides develops 3D processes such as estuarine circulation and tidal straining that become the main upstream salt transport mechanisms. The 3D nature of salinity dynamics, and the role of upstream and downstream processes, suggests that compromising on dimension or extent of the numerical domain can limit the accuracy of predictions of SWI in the delta. The study also showcases the fact that riverbed incision in response to anthropogenic sediment starvation in the last 2 decades has increased stratification and activated or magnified 3D salt transport subprocesses that amplify upstream salt transport. With all the external forces on the delta, namely climate change and an altered hydrological regime by the upstream dams, due to deeper estuarine channels (driven by sand mining and upstream impoundments) compared to its near past, the delta itself has become far more vulnerable to even mild natural events. This exemplifies the fundamental importance of preserving the sediment budget and riverbed levels in protecting the world's deltas against SWI.

scholarly journals ANTROPOCENTRISM EPIDEMIC: THE STUDY OF SOCIAL ACTION OF COMMUNITY TO THE ENVIRONMENT OF JENEBERANG RIVER

2020 ◽  
Vol 4 (1) ◽  
pp. 37
Author(s):  
Hikmawaty Sabar ◽  
Darmawan Salman ◽  
M. Ramli A.T.
Keyword(s):  
Water Pollution ◽  
River Water ◽  
Social Action ◽  
Agricultural Land ◽  
Environmental Crisis ◽  
Mining Activities ◽  
Sand Mining ◽  
Global Environmental ◽  
Entrepreneurial Activities ◽  
And Storage

Nowadays, the global environmental crisis is caused by fundamental philosophical errors in understanding the human way of thinking about themselves, their relation with nature, and their place in the whole ecosystem. In turn, these misconceptions lead to wrong actions. This research aims to comprehensively study the description of the anthropocentric actions of a community about the environment of the Jeneberang River. The approach used in this research is qualitative with a phenomenology method. The result of this research indicates that anthropocentric actions prioritize the desire to fulfill life's needs as if they are free to do anything with nature without considering the preservation and the balanced management of the Jeneberang River environment. There were some community anthropocentric actions found in Jeneberang River community, namely, the establishment of residence, garbage disposal, and storage of stockpiles, the establishment of the brick industry, clearing area for agricultural land, various kinds of entrepreneurial activities, and sand mining activities (have been dismissed since 2015). These actions critically impact the condition of Jeneberang River, worsening problems such as river water pollution, the silt of the river, and flash floods that happened at the beginning of 2019.

scholarly journals SEA SAND MINING ZONATION THROUGH THE INTEGRATION OF OCEAN DYNAMIC AND GIS IN RIAU ISLAND WATERS

2010 ◽  
Vol 4 (1) ◽  
Author(s):  
Asmi M.Napitu ◽  
Dudung M.Hakim ◽  
Nining S.Ningsih ◽  
Albert D.
Keyword(s):  
Image Analysis ◽  
Good Method ◽  
Integrated System ◽  
Mining Activities ◽  
Sand Mining ◽  
Negative Effects ◽  
Landsat Images ◽  
Remote Sensing Technology ◽  
Sensing Technology ◽  
Sea Sand

Sea-sand mining has both advantages particularly in its destructive capabilities. The damages caused by sea-sand mining are mostly due to the unorganized mining zones. In order to minimize the negative effects of mining activities, the well-organized mining zones that have evaluated all related aspects are required. There are several aspects which are closely related to the sea-sand mining zones , one of those is hydro-oceanography aspects in its relation with the sea environments. A comprehensive analysis can be made by integrating hydrooceanography and GIS as a system of both data-organizer and software. This method is supported by using the remote sensing technology as a verification data comparison to the results of hydrooceanography analyses. The application of image analysis as a verification tool is a good method to proof the results given by the numerical simulation model. In this study, we use the Landsat images as the data analysis have indicated that the mining can be continously conducted in several locations without imposing any hazardous impacts to the adjacent environment. By considering the results above, in integrated system between the numerical model and the GIS in highly effective as a foundation to determine the mining zone where the negative effects of the oceanographic-dynamical-changes on the environment due to the mining activities can be easily recognized and predicted. Keyword: Geographic Information System, Hydro-oceanography, Image Analysis.

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