Water

URL

https://ir.vnulib.edu.vn/handle/VNUHCM/31876

Đang hiển thị 1 - 24 của tổng số 58 kết quả

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Longitudinal household trends in access to improved water sources and sanitation in Chi Linh Town, Hai Duong Province, Viet Nam and associated factors
(10/24/2016) Hanh, Tran Thi Tuyet; Long, Tran Khanh; Minh, Hoang Van; Huong, Le Thi Thanh
Objective: This study aims to characterize household trends in access to improved water sources and sanitaton in Chi Linh Town, Hai Duong Province, Vietnam, and to identify factors affecting those trends. ---Method:- Data were extracted from the Chi Linh Health and Demographic Surveillance System (CHILILAB HDSS) database from 2004–2014, which included household access to improved water sources, household access to improved sanitation, and household demographic data. Descriptive statistical analysis and multinominal logistic regression were used. The results showed that over a 10-year period (2004–2014), the proportion of households with access to improved water and improved sanitation increased by 3.7% and 28.3%, respectively. As such, the 2015 Millennium Development Goal targets for safe drinking water and basic sanitation were met. However, 13.5% of households still had unimproved water and sanitation. People who are retired, work in trade or services, or other occupations were 1.49, 1.97, and 1.34 times more likely to have access to improved water and sanitation facilities than farming households, respectively (p < 0.001). Households living in urban areas were 1.84 times more likely than those living in rural areas to have access to improved water sources and improved sanitation facilities (OR =1.84; 95% CI = 1.73–1.96). Non-poor households were 2.12 times more likely to have access to improved water sources and improved sanitation facilities compared to the poor group (OR = 2.12; 95% CI = 2.00–2.25). More efforts are required to increase household access to both improved water and sanitation in Chi Linh Town, focusing on the 13.5% of households currently without access. Similar to situations observed elsewhere in Vietnam and other low- and middle- income countries, there is a need to address socio-economic factors that are associated with inadequate access to improved water sources and sanitation facilities.
Localized recharge processes in the NE Mekong Delta and implications for groundwater quality
(11/11/2022) T. A., Tu; S., Tweed; N. P., Dan
Understanding recharge in the Mekong Delta is critical for the delta's groundwater resources, and requires the investigation of recharge processes at the local scale. In this study of the north eastern area of the Mekong Delta, time-series of environmental tracer data (δ18O, δ2H, major ions and 3H) and markers of rural pollution (NH4 and NO3) were used to highlight localized recharge and impacts on groundwater quality. Results highlighted new hydrological insights into recharge processes, including that the Pleistocene aquifer receives recent recharge (< 60 years), predominantly during high rainfall months (> 100 mm/month). However, due to shallow clay layers there are significant spatial variations in these recharge processes, which were observed in the seasonal fluctuation of groundwater δ18O values in groundwater. Wet season δ18O changes ranged from below analytical uncertainty (≤ 0.10 ‰) to up to 0.56 ‰, and the calculated fraction of rainfall contribution to the aquifer is ≤5 % to 16 %. Rainfall recharge via the acrisol soils results in low groundwater EC (20–55 μS/cm), acidic groundwater (pH 3.6–5.6), and may also have resulted in the low groundwater NO3 concentrations (≤ 5.3 mg NO3/L) at many sites due to adsorption, therefore delaying not reducing NO3 contamination. Site specific variations in nitrogen processes includes increased NO3 (to 29.7 mg/L) from fertiliser transfers or nitrification, and increased NH4 (to 1.4 mg/L) likely due to the recharge of irrigation waters. Unlike other recharge areas across the northern Mekong Delta, this north-eastern region provides a groundwater resource unaffected by arsenic contamination. Therefore, these results should inform on priority areas for protection from further contamination by rural anthropogenic activities.
Past and future terrestrial water storage changes in the lower Mekong River basin: The influences of climatic and non-climatic factors
(11/11/2022) Jinghua, Xiong; Deliang, Chen; Shenglian, Guo
Climate change and human activity such as reservoir operation have altered the hydrological system in the transboundary Mekong River basin (MRB) over decades, urging a need to assess the historical changes and future projections of freshwater availability. Here we examined changes of terrestrial water storage anomalies (TWSA) from the Gravity Recovery and Climate Experiment satellites in the lower MRB during 2003–2020, and subsequently partitioned and attributed them into climate-driven and non-climate-driven components using the WaterGAP hydrological model (WGHM) with and without consideration of human activities, together with a statistical method driven by climatic forcing only. Further, integrated future TWSA was projected under different climate change scenarios during 2030–2099 forced with four downscaled and bias-corrected simulations of four global climate models. Results show a decreasing TWSA trend of −3.7 ± 1.8 mm/a during 2003–2020. The WGHM-based climate-driven TWSA, which is highly correlated with the statistical modeling results, and non-climate-driven part suggests a trend of −0.3 ± 1.4 and 0.01 ± 0.07 mm/a during 2003–2016, respectively. The climate-driven TWSA is well explained by the changes in decreasing precipitation (−1.3 ± 8.5 mm/a) and increasing air temperature (0.05 ± 0.02 ℃/a) spatially and temporally, while the non-climate-driven component is closely linked to human activities such as growing sectoral human withdrawal (0.13 ± 0.14 mm/a), increasing reservoir regulation (0.01 ± 0.08 mm/a), and changing land cover. TWSA under future climate changes is projected to increase from 9.3 ± 21.4 to 12.2 ± 12.2 mm and from 1.6 ± 41.2 to 12.3 ± 30 mm in the near (2040–2059) and far future (2080–2099) under various scenarios comparing with the historical period (2003–2020). Future flood potential, estimated with TWSA and precipitation, was also projected to increase. This study provides important inferences for decision-makers and stakeholders to better understand the water cycle and manage water resources in a changing environment.
Impacts of 25 years of groundwater extraction on subsidence in the Mekong delta, Vietnam
(11/23/2017) Minderhoud, P S J; Erkens, G; V, Pham H; V, Bui T; Others
Many major river deltas in the world are subsiding and consequently become increasingly vulnerable toflooding and storm surges, salinization and permanent inundation. For the Mekong Delta, annual subsidence rates up to several centimetres have been reported. Excessive groundwater extraction is suggested as the main driver. As groundwater levels drop, subsidence is induced through aquifer compaction. Over the past 25 years, groundwater exploitation has increased dramatically, transforming the delta from an almost undisturbed hydrogeological state to a situation with increasing aquifer depletion. Yet the exact contribution of groundwater exploitation to subsidence in the Mekong delta has remained unknown. In this study we deployed a delta-wide modelling approach, comprising a 3D hydrogeological model with an integrated subsidence module. This provides a quantitative spatially-explicit assessment of groundwater extraction-induced subsidence for the entire Mekong delta since the start of widespread overexploitation of the groundwater reserves. Wefind that subsidence related to groundwater extraction has gradually increased in the past decades with highest sinking rates at present. During the past 25 years, the delta sank on average∼18 cm as a consequence of groundwater withdrawal. Current average subsidence rates due to groundwater extraction in our best estimate model amount to 1.1 cm yr 1 , with areas subsiding over 2.5 cm yr 1 , outpacing global sea level rise almost by an order of magnitude. Given the increasing trends in groundwater demand in the delta, the current rates are likely to increase in the near future.
Basic water requirement and water budget study of Bac Ninh province (Vietnam)
(2012-07) Pareta, Kuldeep
Careful use of the limited fresh water resources is the need of the hour. If sufficient measures are not taken up immediately, we will face a crisis which will be detrimental to the very survival of mankind. The Bac Ninh Province of Vietnam is facing a similar problem of acute shortage of drinking water. The water resources in this study area have been estimated by water balance assessment approach. The water balance study using the Thornthwaite and Mather (TM) models with the help of remote sensing and GIS is very helpful in finding out the moisture deficit and moisture surplus for an entire province. The water balance calculation shows that the maximum annual runoff results from the built-up areas/water body followed by agricultural land, and minimum for the barren land and open forest. The annual deficit in the Bac Ninh Province is 1362.2 mm and the annual surplus is 552.7 mm. The total runoff of Bac Ninh Province was calculated as 564.2 mm from the total precipitation of 1384.2 mm. The annual surface water availability for Bac Ninh Province works out at 564.23 mcm. Deducing 5%, which is usually regarded as natural discharge during non-monsoon months, thus region as 536.02 mcm as surface water availability. The current gross demand as drinking & domestic, irrigation purpose / agricultural used, and industrial used is 347.52 mcm (64.83%). The balance surface water availability for future development in the Bac Ninh Province is 188.50 mcm.
Water is for fighting: transnational legal disputes in the Mekong river basin.
(2015) Armstrong, Scott C.
The article discusses the legal issues and complications related to the Mekong River controversy and offers solutions to end this controversy in Southeast Asia. Topics discussed include impacts of proposed construction of several dams on the river on the Mekong ecosystem and regional economy, information on the 1995 Mekong Agreement and Mekong River Commission and provision of the global treaties such as 1997 United Nations Watercourses Convention, Trail Smelter arbitration.
Institutional challenges for peri-urban water supply in Can Tho, Vietnam.
(2015) Huy, Nguyen Ngoc; Phong, Tran Van Giai; Tyler, Stephen
The lack of a secure and clean potable water supply in peri-urban areas is a major source of vulnerability for poor residents on the periphery of rapidly expanding cities in South East Asia. Climate change will increase the demand for clean drinking water, while adversely affecting supply and creating additional water stress in these areas. This study examines the provision of water to peri-urban residents in the rapidly growing city of Can Tho, in Vietnam’s Mekong Delta, which will be heavily affected by climate change. We focus on the institutional structure of water supply, and its relationship to quality and the reliability of the service received by residents. Can Tho’s boundaries include an area of over 1,000 km2, much of which remains agricultural land. About twothirds of the city’s population is located in the built-up urban area, but this population is growing rapidly with migration from surrounding provinces and the rural parts of the city. Water supply is provided in rural areas by the Centre for Rural Water Supply and Sanitation, a local government agency funded through the state budget, and in the city’s urban areas by the Water Supply Company, a city-owned corporation. The two organisations operate in different concession areas, under the oversight of different levels of government, using different tariffs, and they provide water to different quality standards using very different technologies. There are no effective mechanisms for administrative or planning collaboration. This paper describes the institutional factors that lead to these differences, and explains how they operate as barriers to the expansion of the urban water supply system in the rapidly growing peri-urban areas of Can Tho. We suggest measures to overcome these barriers and simplify the expansion of urban water supply for the benefit of peri-urban residents.
The challenges of water governance in Ho Chi Minh City
(2015-05) Leeuwen, K. Van; Dan, Nguyen Phuoc; Dieperink, Carel
Population growth, urbanization, pollution and climate change pose urgent water challenges in cities. In this study the sustainability of integrated water resources management in Ho Chi Minh City (HCMC) was evaluated using the City Blueprint approach. The City Blueprint is a set of 24 dedicated indicators divided over 8 categories, i.e., water security, water quality, drinking water, sanitation, infrastructure, climate robustness, biodiversity and attractiveness and governance including public participation. The analysis showed that the rapid increase of water use for urban, industrial and agricultural activities in HCMC has resulted in depletion of groundwater and severe pollution of both groundwater and surface water. Surface water quality, groundwater quality, biodiversity, and the sanitation of domestic and industrial waste water are matters that need serious improvement. Current and future water supply in HCMC is at risk. HCMC can cope with it, but the seven governance gaps as described by the OECD are major obstacles for HCMC. Rainwater harvesting, pollution reduction, as well as wastewater reuse are among the practical options. Wastewater reuse could lower the water stress index to 10%. The window to do this is narrow and rapidly closing as a result of the unprecedented urbanization and economic growth of this region.
Water and sanitation entrepreneurs in Indonesia, Vietnam and Timor-Leste: Traits, drivers and challenges.
(2016) Willetts, Juliet; Murta, Janina; Gero, Anna
This working paper provides insights drawn from three country-level studies on the motivations, drivers and barriers experienced by 172 water and sanitation enterprises in Indonesia, Vietnam and Timor-Leste. Entrepreneurial and pro-social traits are explored, including their connections with enterprise success. Key success factors and typical challenges are also highlighted.
Good governance as managerialism: rationalisation and international donors in Vietnam's rural water supply and sanitation sector.
(2016) Reis, Nadine
Donors’ appreciation of their relationship with Vietnam as a ‘mature development partnership’ requires explanation. Drawing on Rural Water Supply and Sanitation policy, the article argues that the success of donor collaboration with Vietnam is based on Vietnamese political culture coincidentally aligning with a managerialist ‘world culture’, presently extant in the form of neoliberal ‘good governance’ development orthodoxy. The article shows that Vietnam ‘delivers’ rationalised development policy to international donors through its system of state administration and planning, the implementation of target-oriented planning and the role of statistics in the policy process. The strength of the ‘darling’ partnership is explained in relation to this cultural dimension of legitimacy creation through the performance of rational development planning and administration.
Water allocation in trans-boundary river basin during droughts: A case study of Vu Gia Thu Bon basin, Vietnam.
(2018) Duong, Bui Du; Anh, Nguyen Hung; Nuong, Bui Thi; Others
Water is essential for all aspects of life. Its finite availability requires an efficient and equal water allocation for different uses, particularly when there is a growing competition from increasing population and unprecedented climate change impacts. During drought periods when water supply is unable to meet the business-as-usual demand, an equitable water allocation priority order is essential to ensure that priority needs of society are met. This study proposes a basin water allocation framework (BWAF) based on the Analytical Hierarchy Process (AHP) and Decision Analysis Module for Excel (DAME) to provide an evidence-based toolset, supporting decision-making processes in determining how to optimally allocate water among different water users. The framework allows the users to customize the scenarios, criteria and variants that produce fair priority order results in accordance to the identified objectives. The framework is examined in a transboundary Vu Gia Thu Bon River basin, Vietnam where two provinces QuangNam and DaNang share the same river basin. Considering only surface water resources and evaluating the economic efficiency of four different sectors – cultivation, animal husbandry, industry and aquaculture, the framework provides different priority orders for each province and the entire basin in water shortage months. Findings can not only further contribute to the literature on drought risk management frameworks but also provide a useful and easy-to-use toolset for decision makers to respond and adapt to droughts in practice.
Water allocation in trans-boundary river basin during droughts: A case study of Vu Gia Thu Bon basin, Vietnam
(2018) Duong, Bui Du; Anh, Nguyen Hung; Tien, Du Le Thuy; Nuong, Bui Thi; Others
Water is essential for all aspects of life. Its finite availability requires an efficient and equal water allocation for different uses, particularly when there is a growing competition from increasing population and unprecedented climate change impacts. During drought periods when water supply is unable to meet the business-as-usual demand, an equitable water allocation priority order is essential to ensure that priority needs of society are met. This study proposes a basin water allocation framework (BWAF) based on the Analytical Hierarchy Process (AHP) and Decision Analysis Module for Excel (DAME) to provide an evidence-based toolset, supporting decision-making processes in determining how to optimally allocate water among different water users. The framework allows the users to customize the scenarios, criteria and variants that produce fair priority order results in accordance to the identified objectives. The framework is examined in a transboundary Vu Gia Thu Bon River basin, Vietnam where two provinces QuangNam and DaNang share the same river basin. Considering only surface water resources and evaluating the economic efficiency of four different sectors – cultivation, animal husbandry, industry and aquaculture, the framework provides different priority orders for each province and the entire basin in water shortage months. Findings can not only further contribute to the literature on drought risk management frameworks but also provide a useful and easy-to-use toolset for decision makers to respond and adapt to droughts in practice.
Vietnam’s future water usage model: a controlled living experiment.
(2018) Toyosada, Kanako; Otani, Takayuki; Shimizu, Yasutoshi; Takata, Hiroshi; Sakamoto, Kazuhiko; Murakawa, Saburo; Managi, Shunsuke
The purpose of this study was to explore the water usage profile of future Vietnamese households by carrying out a controlled living experiment with Vietnamese high-income households. By studying showering time, flow rate and toilet-use frequency of these households, the study revealed the water usage believed to be representative of future households in light of continued urbanization. This study also determined that the average time of showering was 9.7 minutes per person per day with an average flow rate of 12 L/minute for the existing shower head and 6.6 L/minute for the water-saving shower head. Toilet usage frequency was 5.25 times per person per day, and there was no difference with the results for an average (middle-income) household.
Double exposures: Future water security across Urban Southeast Asia.
(2019) Lorenzo, Theresa E.; Kinzig, Ann P.
Southeast Asia is one of the most dynamic regions in the world in terms of economic growth and urbanization. At the same time, the region is also prone to multiple hydro-meteorological disasters, which are projected to be intensified by climate change. This paper analyzes the combined effect of economic development and climate change on the future water security of middle-income Southeast Asian countries using the double exposure framework, focusing on the effects in urban areas. A review of the existing literature reveals unequal water security outcomes across the region as a result of combined climate, economic, and urbanization pressures. The water supply and sanitation infrastructure of upper-middle-income Southeast Asian countries are vulnerable to damage from intensified disasters, potentially decreasing both immediate and longer-term water quality. In lower-middle-income countries, the water quality will be the more important water security challenge in the short-term as opposed to water quantity, mainly due to the fast growth of industries. Lower-middle-income countries, though less vulnerable to disasters, will still have lower future water security compared to upper-middle-income countries, as they have less capacity to address water quality and quantity challenges brought about by both industrial growth and urbanization. Across the region, future water quantity and quality challenges may result in slower economic and urban growth if not planned adequately.
Effects of multi-dike protection systems on surface water quality in the Vietnamese Mekong Delta
(2019) Minh, Huynh Vuong Thu; Ty, Tran Van; Dat, Tran Quoc; Others
The Vietnamese Mekong Delta (VMD) is one of the largest rice-growing areas in Vietnam, and exports a huge amount of rice products to destinations around the world. Multi-dike protection systems have been built to prevent flooding, and have supported agricultural intensification since the early 1990s. Semi-dike and full-dike systems have been used to grow double and triple rice, respectively. Only a small number of studies have been conducted to evaluate the water quality in the VMD. This study aimed to analyze the spatiotemporal variation of water quality inside the dike-protected area. Surface water samples were collected in the dry and wet seasons at 35 locations. We used multivariate statistical analyses to examine various water quality parameters. The mean concentrations of COD, NH4 +, NO3 −, PO4 3−, EC, and turbidity were significantly higher in water samples inside the full-dike system than in water samples from outside the full-dike systems and inside the semi-dike systems in both seasons. High concentrations of PO4 3− were detected in most of the primary canals along which residential, tourist areas and local markets were settled. However, NO3 − was mainly found to be higher in secondary canals, where chemical fertilizers were used for rice intensification inside the dike system. Water control infrastructures are useful for preventing flood hazards. However, this has an adverse effect on maintaining water quality in the study area.
Rainwater for drinking in Vietnam: Barriers and strategies
(2019) Thuy, Bui Thi; Dung, Dao Anh; Han, Mooyong; Canh, Nguyen Duc; Others
For many decades in Vietnam, rainwater harvesting has been widely used as a nature-based solution in rural areas, aiming at good-quality drinking water with low cost and little energy. Recently, rainwater for drinking has attracted much attention from the Vietnam government. Furthermore, despite its efforts, the outcomes are not as expected due to local barriers. This paper reviewed rainwater for drinking demonstration projects in some specific areas of Vietnam, with identification of the technical, economic, and social barriers, further suggesting possible overcome strategies. A lesson learnt from this study would be the principle of promoting rainwater for drinking in developing countries, looking forward to sustainability.
Effects of multi-dike protection systems on surface water quality in the Vietnamese Mekong Delta
(2019) Minh, Huynh Vuong Thu; Ty, Tran Van; Dat, Tran Quoc; Others
The Vietnamese Mekong Delta (VMD) is one of the largest rice-growing areas in Vietnam, and exports a huge amount of rice products to destinations around the world. Multi-dike protection systems have been built to prevent flooding, and have supported agricultural intensification since the early 1990s. Semi-dike and full-dike systems have been used to grow double and triple rice, respectively. Only a small number of studies have been conducted to evaluate the water quality in the VMD. This study aimed to analyze the spatiotemporal variation of water quality inside the dike-protected area. Surface water samples were collected in the dry and wet seasons at 35 locations. We used multivariate statistical analyses to examine various water quality parameters. The mean concentrations of COD, NH4 +, NO3 −, PO4 3−, EC, and turbidity were significantly higher in water samples inside the full-dike system than in water samples from outside the full-dike systems and inside the semi-dike systems in both seasons. High concentrations of PO4 3− were detected in most of the primary canals along which residential, tourist areas and local markets were settled. However, NO3 − was mainly found to be higher in secondary canals, where chemical fertilizers were used for rice intensification inside the dike system. Water control infrastructures are useful for preventing flood hazards. However, this has an adverse effect on maintaining water quality in the study area.
Allocating water in the Mekong River basin during the dry season
(2019) Yuan, Liang; He, Weijun; Liao, Zaiyi; Others
With population numbers increasing and anthropogenic climate change, the amount of available fresh water is declining. This scenario can lead to an increase in the occurrence of water conflicts, especially in transboundary river basins. Prevention strategies to avert water conflicts by designing a fair, efficient, and sustainable water allocation framework are needed. Taking into account the socioeconomic and environmental differences among the riparian countries is one of the most important features an allocation scheme should have. In this article, bankruptcy and bargaining games were used to construct a new weighted water allocation model. The proposed method was applied to allocate the contested water capital of the Mekong River during the dry season. The Mekong River originates in China and flows through Myanmar, Laos, Thailand, Cambodia, and Vietnam. The results of the allocation showed that, except for China and Vietnam, all the other riparian countries get their full claim of the water demand from the river. The water allocation payoffs satisfy individual rationality, Pareto optimality, and maximization of the group utility. Therefore, the allocation outputs from the proposed scheme are self-enforceable and sustainable.
Effects of multi-dike protection systems on surface water quality in the Vietnamese Mekong Delta
(2019) Minh, Huynh Vuong Thu; Ty, Tran Van; Dat, Tran Quoc; Others
The Vietnamese Mekong Delta (VMD) is one of the largest rice-growing areas in Vietnam, and exports a huge amount of rice products to destinations around the world. Multi-dike protection systems have been built to prevent flooding, and have supported agricultural intensification since the early 1990s. Semi-dike and full-dike systems have been used to grow double and triple rice, respectively. Only a small number of studies have been conducted to evaluate the water quality in the VMD. This study aimed to analyze the spatiotemporal variation of water quality inside the dike-protected area. Surface water samples were collected in the dry and wet seasons at 35 locations. We used multivariate statistical analyses to examine various water quality parameters. The mean concentrations of COD, NH4 +, NO3 −, PO4 3−, EC, and turbidity were significantly higher in water samples inside the full-dike system than in water samples from outside the full-dike systems and inside the semi-dike systems in both seasons. High concentrations of PO4 3− were detected in most of the primary canals along which residential, tourist areas and local markets were settled. However, NO3 − was mainly found to be higher in secondary canals, where chemical fertilizers were used for rice intensification inside the dike system. Water control infrastructures are useful for preventing flood hazards. However, this has an adverse effect on maintaining water quality in the study area.
Effects of multi-dike protection systems on surface water quality in the Vietnamese Mekong Delta
(2019) Minh, Huynh Vuong Thu; Ty, Tran Van; Dat, Tran Quoc; Others
The Vietnamese Mekong Delta (VMD) is one of the largest rice-growing areas in Vietnam, and exports a huge amount of rice products to destinations around the world. Multi-dike protection systems have been built to prevent flooding, and have supported agricultural intensification since the early 1990s. Semi-dike and full-dike systems have been used to grow double and triple rice, respectively. Only a small number of studies have been conducted to evaluate the water quality in the VMD. This study aimed to analyze the spatiotemporal variation of water quality inside the dike-protected area. Surface water samples were collected in the dry and wet seasons at 35 locations. We used multivariate statistical analyses to examine various water quality parameters. The mean concentrations of COD, NH4 +, NO3 −, PO4 3−, EC, and turbidity were significantly higher in water samples inside the full-dike system than in water samples from outside the full-dike systems and inside the semi-dike systems in both seasons. High concentrations of PO4 3− were detected in most of the primary canals along which residential, tourist areas and local markets were settled. However, NO3 − was mainly found to be higher in secondary canals, where chemical fertilizers were used for rice intensification inside the dike system. Water control infrastructures are useful for preventing flood hazards. However, this has an adverse effect on maintaining water quality in the study area.
Allocating water in the Mekong River basin during the dry season
(2019) Yuan, Liang; He, Weijun; Liao, Zaiyi; Others
With population numbers increasing and anthropogenic climate change, the amount of available fresh water is declining. This scenario can lead to an increase in the occurrence of water conflicts, especially in transboundary river basins. Prevention strategies to avert water conflicts by designing a fair, efficient, and sustainable water allocation framework are needed. Taking into account the socioeconomic and environmental differences among the riparian countries is one of the most important features an allocation scheme should have. In this article, bankruptcy and bargaining games were used to construct a new weighted water allocation model. The proposed method was applied to allocate the contested water capital of the Mekong River during the dry season. The Mekong River originates in China and flows through Myanmar, Laos, Thailand, Cambodia, and Vietnam. The results of the allocation showed that, except for China and Vietnam, all the other riparian countries get their full claim of the water demand from the river. The water allocation payoffs satisfy individual rationality, Pareto optimality, and maximization of the group utility. Therefore, the allocation outputs from the proposed scheme are self-enforceable and sustainable.
Determine the vulnerability of urban surface water resources in Rach Gia City, Vietnam using geographic information system.
(2019) Hai, Dinh Tuan; Phin, Trinh Thi
Rach Gia city is located on the west coast of Mekong Delta, Vietnam. Due to the high salinity intrusion of underground aquifers, urban surface water is the main source of mining. Water retention consists of reservoirs with around 600,000 m3 and 3.2 km length of a canal. These resources are taken from rivers and canals in the area. However, urban surface water in the area is contaminated by human activities such as wastewater discharge and waterway traffic. Furthermore, in dry seasons when water levels in rivers and canals reach low salinity intrusion infiltrate into rivers, affecting water supplies. Therefore, it is necessary to identify the vulnerabilities of pollution on reservoirs and canals. This study employs a spatial analysis model integrating several previously defined parameters such as slope, land use, drainage network density, runoff and salinity levels. They will be prioritized and weighted and then integrated into a geographic information system (GIS). Results indicated drainage network density and land use are majors to cause vulnerability of pollution on an urban surface water resource. Despite the subjectivity involved in the weighing of analytic hierarchy process (AHP), the study determined vulnerability levels as well as factors that cause pollution. These results will support to protect urban surface water resources.
Effects of multi-dike protection systems on surface water quality in the Vietnamese Mekong Delta
(2019) Minh, Huynh Vuong Thu; Ty, Tran Van; Dat, Tran Quoc; Others
The Vietnamese Mekong Delta (VMD) is one of the largest rice-growing areas in Vietnam, and exports a huge amount of rice products to destinations around the world. Multi-dike protection systems have been built to prevent flooding, and have supported agricultural intensification since the early 1990s. Semi-dike and full-dike systems have been used to grow double and triple rice, respectively. Only a small number of studies have been conducted to evaluate the water quality in the VMD. This study aimed to analyze the spatiotemporal variation of water quality inside the dike-protected area. Surface water samples were collected in the dry and wet seasons at 35 locations. We used multivariate statistical analyses to examine various water quality parameters. The mean concentrations of COD, NH4 +, NO3 −, PO4 3−, EC, and turbidity were significantly higher in water samples inside the full-dike system than in water samples from outside the full-dike systems and inside the semi-dike systems in both seasons. High concentrations of PO4 3− were detected in most of the primary canals along which residential, tourist areas and local markets were settled. However, NO3 − was mainly found to be higher in secondary canals, where chemical fertilizers were used for rice intensification inside the dike system. Water control infrastructures are useful for preventing flood hazards. However, this has an adverse effect on maintaining water quality in the study area.
Evaluating current water quality monitoring system on Hau River, Mekong Delta, Vietnam Using multivariate statistical techniques.
(2020) Giao, Nguyen Thanh
This study aims to assess the sampling sites and frequencies of sampling of the existing surface water quality monitoring on Hau River using multivariate analysis techniques. Principal Component Analysis (PCA) and Cluster Analysis (CA) were used to analyze the water quality monitoring data collected every month in 2018 from 8 sampling stations. Surface water quality parameters including pH, temperature, dissolved oxygen (DO), total suspended solids (TSS), nitrate (N-NO3-), phosphate (P-PO43-), chemical oxygen demand (COD) and coliforms were used in the PCA and CA analyses. The findings indicated that the Hau River water quality was polluted by TSS, COD and coliforms in which COD was high in dry season, TSS was high in wet season and coliforms were high all year round. The PCA revealed that pH, temperature, DO, TSS, N-NO3-, P-PO43-, COD and coliforms influenced on the water quality, therefore, relevant for examination in the water samples. These water quality variables were affected by various polluting sources, for examples, runoff, human activities, and hydrological influence. Cluster analysis suggested that the current monitoring program could be reduced from 8 to 3-4 points and 12 to 3-4 times per year. This monitoring program could save the total budget for up to 42%. The findings of the present study could be useful to the policy maker especially to those who are dealing with surface water monitoring systems. The multivariate statistical techniques could be used to assess the surface water quality monitoring network.

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Water

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Duyệt Water theo Năm xuất bản

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