Groundwater status and associated issues in the Mekong-Lancang River Basin: International collaborations to achieve sustainable groundwater resources          下载免费PDF全文

Eunhee Lee  Kyoochul Ha  Nguyen Thi Minh Ngoc  Adichat Surinkum  Ramasamy Jayakumar  Yongje Kim  Kamaludin Bin Hassan 《地下水科学与工程》2017,5(1):1-13

Groundwater is an important and readily available source of fresh water in the Mekong-Lancang River Basin. With a rapid population growth and increasing human activities, an increasing number of countries in the Mekong-Lancang River Basin are experiencing depleted and degraded groundwater supplies. In transboundary river basins, such as the Mekong-Lancang River, prioritizing the use of the shared aquifer by one riparian government may affect the opportunities of other riparian governments and lead to potential water conflicts between neighboring countries. To promote the sharing of strategies and information for the sustainable and equitable use of water resources of the shared basin, international collaborative workshops on groundwater resources have been organized for all Mekong-Lancang River countries. These workshops provide an opportunity to communicate and discuss nationally sensitive issues on groundwater by the associated countries, with topics covering multiple aspects of groundwater, such as the groundwater status in the basin, quality issues, water use conflicts, hydrological information gaps, management policies and capacity building for successful water resource management. Consensus has been reached by all countries on the importance of catchment-based groundwater management and the need for close communication among the countries. Strategies for managing transboundary aquifer issues must foster international collaboration based on the regional network, influence national networks and enhance the capacity to building maps and monitoring systems based on associated databases. The sustainability of water resources cannot be achieved without the integrated involvement and contributions by multiple countries and various stakeholders. Therefore, collaborative workshops provide a great opportunity to further our understanding of the hydrologic processes of the Mekong River Basin, share the benefits of the aquifer and provide a strategy and vision for sustainable water resource management in the Mekong-Lancang River countries.  相似文献   

Starch-assisted sol–gel synthesis of magnetic CuFe<Subscript>2</Subscript>O<Subscript>4</Subscript> powder as photo-Fenton catalysts in the presence of oxalic acid     

Thi Thao Dinh  To Quyen Nguyen  Gia Co Quan  Vo Dong Nghi Nguyen  Hon Quoc Tran  Tien Khoa Le 《International Journal of Environmental Science and Technology》2017,14(12):2613-2622

Magnetic photo-Fenton catalysts based on spinel CuFe₂O₄ were successfully prepared by the starch-assisted sol–gel method. Various synthetic conditions such as annealing temperatures (700, 800 and 900 °C) and molar ratios of Cu²⁺/Fe³⁺/C₆H₁₀O₅ in the precursor solution (from 1:2:2 to 1:2:4) were, respectively, used in order to study the influences of annealing temperatures and precursor starch contents on the magnetic and catalytic properties of CuFe₂O₄ powders. The photo-Fenton catalytic activity was evaluated via the degradation of methylene blue under ultraviolet and visible irradiation with H₂C₂O₄ as a new oxidizing agent. According to the results, when the annealing temperature increased to 800 °C, the spinel CuFe₂O₄ phase amount was increased, which strongly enhances the photo-Fenton catalytic performance. However, above 800 °C, the catalytic activity was reduced, due to the increase in particle size. The starch content also affected the surface Cu²⁺ content and the particle size of catalysts. The catalyst prepared at 800 °C with the molar Cu²⁺/Fe³⁺/C₆H₁₀O₅ ratio of 1:2:3 presented the best photo-Fenton performance, owing to its highest surface Cu²⁺ content. This catalyst also exhibits ferromagnetic properties (saturation magnetization of 25.836 emu/g and coercivity of 1010.23 Oe), which allows them to be easily separated from the solution by a magnet.  相似文献   

Carbon dioxide stripping from anaerobic digestate of food waste using two types of aerators     

J. Kang  G. Kwon  J. H. Nam  Y. O. Kim  D. Jahng 《International Journal of Environmental Science and Technology》2017,14(7):1397-1408

Anaerobic digestate of organic wastes often contains high concentrations of ammonia and carbon dioxide. Ammonia can be removed from digestate by air stripping at elevated pH. However, it is difficult to increase pH of the digestate because dissolved carbon dioxide transforms into bicarbonate and carbonate ions. Thus, carbon dioxide in digestate needs to be removed to reduce alkali consumption in ammonia stripping process. This study aimed to optimize and compare the performances of diffused and packed tower aerators for anaerobic digestate of food waste. The diffused aerator removed 82.1% of dissolved carbon dioxide and 13.7% of total inorganic carbon, and increased pH of digestate from pH 7.87 to pH 8.53, under the following optimized conditions; digestate temperature of 45 °C, air flow rate of three volumes of air added to a unit volume of liquid per minute, aspect ratio of 2, agitation speed of 500 rpm with a turbine impeller, and retention time of 10 min. Operating conditions of the packed tower aerator were also optimized, and it was found that the packed tower aerator removed 15% and 44% less dissolved carbon dioxide and total inorganic carbon, respectively, than the diffused aerator. It was also found that overall coefficients of carbon dioxide mass transfer from liquid to gas phase determined the final pH of digestate and removal efficiencies of carbon species.  相似文献   

Radiochemical separation and determination of radium-228 in bottled mineral waters by low level gamma spectrometry and its committed effective dose     

Mihriban Şahin  Abdullah Dirican  Namık Kemal Şahin 《Environmental Earth Sciences》2017,76(23):795

?The gross beta and ²²⁸Ra radioactivity measurements in mineral waters were performed by proportional counter and gamma spectrometry, respectively, in this study. The natural mineral water samples were collected from various regions of Turkey for this study. Gross beta activities have been determined according to the United States Environmental Protection Agency standard method (EPA 900). In the case that the gross beta activity was determined to be greater than 1 Bq/L, then the ²²⁸Ra activity concentration in the related mineral water sample was specifically measured. ²²⁸Ra activity in mineral water samples was determined by high-purity germanium (HPGe) detector. The photopeak efficiencies were calculated by modeling the sample geometry and the detector in Canberra software LabSOCS. The gross beta activities in the eight of 32 bottled mineral water samples were greater than 1 Bq/L. ²²⁸Ra activity concentrations in bottled mineral waters were determined within 0.100–1.04 Bq/L. The committed effective doses were calculated for three different scenarios according to mineral water consumption rates.  相似文献   

Morphological Change in the Northern Red River Delta,Vietnam     

Vuong Van Bui  Daidu Fan  Dac Ve Nguyen  Dinh Lan Tran  Duc Thanh Tran  Van Long Hoang  Thi Hong Hanh Nguyen 《中国海洋大学学报(英文版)》2018,17(6):1272-1280

Coastal erosion has become a worldwide concern, typically in the densely populated Asian mega-river deltas. Severe coastal erosion in the southern Red River Delta(RRD) has been intensively studied. Coastal morphological change in the northern RRD was examined in detail through DEM(Digital Elevation Model) analysis based on time series of bathymetrical maps(1965–2004) and Landsat images(1975–2015) in this study. The results show that the northern RRD is featured by rapid coastal accretion in the past few decades, although suspended sediment flux has dropped by roughly 60% after the completeness of Hoa Binh Dam(HBD) in 1988 and relative sea level rose at 1.9 mm yr~(-1). However, accretion at the outer part of subtidal shoals and platforms was observed to slow down quickly or even turned into erosion in the last two decades. The resuspended sediments from the erosion zone can be transported landward to replenish the inner coastal zone, keeping the latter accretion in the near future to compensate for the sediment discharge decrease from the river. However, this lag effect should be terminated soon if other adverse effects go worse, e.g., damming rivers, sea-level rising, strengthening storms, land reclamation and other poor-designed coastal engineering. Coastal planners and managers should pay full attention to these changes.  相似文献   

Establishing an early warning system for flash floods in Hoang Su Phi District,Ha Giang Province,Vietnam     

Thach Ngoc Nguyen  Canh Xuan Pham  Huy Quoc Nguyen  Toan Ngo Bao Dang 《Singapore journal of tropical geography》2019,40(2):312-333

Hoang Su Phi is a mountainous district in Ha Giang province, Vietnam. When the rainy season arrives in these parts, flash floods (besides landslides), frequently occur in many areas, seriously affecting the socio‐economic condition of the district. Therefore, in this paper, we have developed an early warning system for flash floods, established based on a geomorphological and hydrological approach. The basic principle underlying this system is the fact that flash floods will often occur where there is high potential risk with sufficient rainfall. In the model, eight parameters of the basin were used to build a potential flash flood map. Using the spatial processing module in an open source software, early predictions from automatic weather stations were interpolated and processed online to produce a potential risk map. Depending on the threshold of precipitation values, the results determined locations where flash flood may occur at various flash flood risk indices (FFRI). The system may be applied to support provision of early flash flood warning up to 1?6 days in advance in the district, allowing the local government ample time to make appropriate decisions on the prevention and/or mitigation of damages caused by flash flood hazards.  相似文献   

Predictability of the wintertime 500 hPa geopotential height over Ural-Siberia in the NCEP climate forecast system     

Qiao  Shaobo  Zou  Meng  Cheung  Ho Nam  Zhou  Wen  Li  Qingxiang  Feng  Guolin  Dong  Wenjie 《Climate Dynamics》2020,54(3):1591-1606

Climate Dynamics - Using hindcast and forecast data from the National Centers for Environmental Prediction (NCEP) climate forecast system version 2 (CFSv2) for the period 1982–2017, we...  相似文献   

On the importance of river hydrodynamics in simulating groundwater levels and baseflows     

Tran Quoc Quan  Pieter Meert  Marijke Huysmans  Patrick Willems 《水文研究》2020,34(8):1754-1767

Research to date affirmed the key role of stream–aquifer interactions in integrated water resources management. The importance of river hydrodynamics on the spatial and temporal behaviour of groundwater was, however, not yet fully investigated. In contrast to the common approach where topography-based estimates of riverbed elevation may lead to inappropriate discretization and constant river stages, this study couples a fully hydrodynamic and one-dimensional river model to a two-dimensional catchment hydrological model. The surface and subsurface runoff, groundwater, and river components are integrated into a single modelling framework. The coupled model was applied to a medium sized catchment in Belgium with three model setups, in which the level of detail of representation of river hydrodynamics varies. Further model iterations were carried out for the most exhaustive setup to assess the importance of the bi-directional interactions between model components. Results show that higher details of river hydrodynamics help to improve the simulation of time-averaged groundwater levels. However, the impacts were not that clear for the time-varying groundwater levels. Moreover, visual and statistical model performance evaluation indicates a strong enhancement of the coupled models compared to the output from the hydrological model with respect to river discharge observations at catchment outlet and at internal stations. It also reveals the impact of river hydrodynamics on groundwater discharges when the most detailed setting delivered the highest performance among the three coupled models.  相似文献   

A technique for prediction of SPEs from solar radio flux by statistical analysis,ANN and GA     

Kyong Nam Kim  Sun Ae Sin  Kum Ae Song  Jin Hyok Kong 《Astrophysics and Space Science》2018,363(8):170

Solar Radio Flux (SRF) is the significant index in easily evaluating everyday solar activities. From the statistical analysis of SRF at 2800 MHz, 1415 MHz and 610 MHz from 1976 to 1994, and only 111 Solar Proton Events (SPEs) occurring in the same period, we have given the statistical relation between them. In fact, there occurred a total of 131 SPEs in the same period, but we dealt with only 111 SPEs of them, because of lack of SRF data in SGD (2800 MHz, 1415 MHz and 610 MHz). We also discussed the possible parameters of SRF at 2800 MHz, 1415 MHz and 610 MHz for prediction of SPEs by statistical analysis, Artificial Neural Network (ANN) and Genetic Algorithm (GA) using MATLAB. In this study, we used some parameters: the daily total SRF, the overall rate of increase of SRF and SPEs.  相似文献   

Prediction of Blast-Induced Ground Vibration Intensity in Open-Pit Mines Using Unmanned Aerial Vehicle and a Novel Intelligence System     

Bui  Xuan-Nam  Choi  Yosoon  Atrushkevich  Victor  Nguyen  Hoang  Tran  Quang-Hieu  Long  Nguyen Quoc  Hoang  Hung-Thang 《Natural Resources Research》2020,29(2):771-790

Natural Resources Research - Predicting and reducing blast-induced ground vibrations is a common concern among engineers and mining enterprises. Dealing with these vibrations is a challenging issue...  相似文献