CURRENT STATE OF SALT INTRUSION IN THE MEKONG DELTA IN VIETNAM

2020 ◽  
pp. 74-80
Author(s):  
Nguyen Thi Thuy Nhung Nguyen Thi Thuy Nhung ◽  
Keyword(s):  
Power Plants ◽  
Salt Water ◽  
High Tide ◽  
Mekong Delta ◽  
Dry Season ◽  
Mekong River ◽  
Circulation System ◽  
Deep Penetration ◽  
Hydroelectric Power ◽  
Salt Intrusion

The study aims to determine the evolution of salt intrusion in the Mekong Delta in Vietnam. Salt water appeared in the mouths of rivers many years ago, but its values in 2019-2020 are considered the highest in the history of observations and surpass the data of 2016 (the year with the highest salinity). In 2020, the phenomenon of salt invasion will strongly manifest itself in the Mekong Delta in Vietnam (in the lower reaches of the Mekong River), the penetration of salt water deep into the mainland and the marginal salinity of 4 (g/l) deeper than 5-25 km, depending on the range. The main reason for this is the change in the flow of water from the headwaters. During the dry season, the flow in the estuary is completely dependent on the flow of water from the upper Mekong River, and the construction of hydroelectric power plants affects the water content of the river below the dams. The second reason is the inefficient operation of the fresh water circulation system between rivers during the dry season in Vietnam. Some other causes are related to climate change, such as rising sea levels at high tide, which allows salt water to flow inland from the mouth, as well as a rather wide shape of the mouth and deep penetration into the land, which contributes to faster penetration. All this negatively affects the environment and sustainable economic development of the Mekong Delta in Viet Nam.

scholarly journals Salt intrusion in the Pungue estuary, Mozambique: effect of sand banks as a natural temporary salt intrusion barrier

2008 ◽  
Vol 5 (4) ◽  
pp. 2523-2542 ◽  
Author(s):  
S. Graas ◽  
H. H. G. Savenije
Keyword(s):  
Water Supply ◽  
Water Intake ◽  
Salt Water ◽  
Water Discharge ◽  
Dry Season ◽  
Salt Water Intrusion ◽  
Salt Intrusion ◽  
Water Intrusion ◽  
Salinity Levels ◽  
Monthly Discharge

Abstract. This paper presents a salt intrusion model for the Pungue estuary with the aim to determine the minimum discharge required to prevent the salt intrusion from reaching the water intake situated 82 km from the estuary mouth. The Pungue river is shared between Zimbabwe and Mozambique and has a large variation in precipitation and runoff. The mean monthly discharge can be as low as 8 m3/s and as high as 893 m3/s. The second largest city of Mozambique, Beira, relies on the Pungue for its water supply. In the dry season it frequently occurs that the water intake has to be ceased because the salinity of the Pungue is too high. The salt intrusion model used in this paper is based on a fully analytical and predictive theory which is confronted with measurements of salt intrusion and estuary topography. The paper presents the collection of estuary characteristics and the salt water intrusion measurements that were obtained by field measurements in 1993 and 2002. Using these data the salt intrusion model has successfully been applied. During salinity intrusion measurements in the dry season of 1993 it was observed that sand banks in the middle zone of the estuary prevented the salt water from intruding further upstream, resulting in lower salinity levels upstream than the theoretical salt water intrusion model predicts. This effect occurs during ebb of neap and average tides and can reduce the salt water intrusion by 10 km. The model indicates that in a natural situation a minimum monthly discharge of 12 m3/s is required to maintain acceptable salinity levels during high water and spring tide near the water intake. The actual water discharge upstream of the water intake has to be higher, since this minimum discharge does not take into account the water abstracted for irrigation and/or urban water supply. Current water abstractions lead to salt water intrusion near the water intake at approximately 10% of the time. The model indicates that an additional water abstraction of 5 m3/s will lead to an increase in salt water reaching the intake at 10% of the time. During neap tide the sand banks act as a temporary natural salt intrusion barrier reducing the chance of salt water reaching the water intake.

scholarly journals Development of Rice Husk Power Plants Based on Clean Development Mechanism: A Case Study in Mekong River Delta, Vietnam

2021 ◽  
Vol 13 (12) ◽  
pp. 6950
Author(s):  
Nguyen Van Song ◽  
Thai Van Ha ◽  
Tran Duc Thuan ◽  
Nguyen Van Hanh ◽  
Dinh Van Tien ◽  
...  
Keyword(s):  
Power Generation ◽  
Rice Husk ◽  
Clean Development Mechanism ◽  
Power Plants ◽  
Carbon Dioxide Emission ◽  
Mekong Delta ◽  
River Delta ◽  
Mekong River ◽  
Mekong River Delta ◽  
Development Mechanism

In this research, we planned and conducted estimations for developing a pilot-scale Clean Development Mechanism (CDM) project for group plant activities in the Vietnam electricity/energy sector. The overall aim of this paper is to assess the power generation potential of rice husk power plants in the Mekong Delta. We intend to set up a rice husk energy balance flowchart for the whole Mekong River Delta in the year 2021 and suggest policies that can be used for the power generation of unused rice husk, to avoid having them pollute rivers and canals. We put forward a safe and environmentally friendly solution to thoroughly minimize the current serious pollution of rivers and canals in the Mekong River Delta caused by the increasing quantity of unused rice husk. The results of this paper are based on the estimation of electricity potential of a group of rice husk power development plants in the Mekong River Delta with a capacity of 11 MW per plant, including carbon dioxide emission reductions (CERs) and CER credits, along with estimations of their economic criteria (NPV, B/C, IRR), both W/CDM and W/O CDM.

scholarly journals CREATIVE ENVIRONMENTAL ENERGY TECHNOLOGY ASSESSMENT HYDROELECTRIC POWER PLANT (CASE STUDY OF WONOGIRI RESERVOIR)

2017 ◽  
Vol 2 (3) ◽  
pp. 101 ◽  
Author(s):  
Feby Hidayani ◽  
Yohanes Sardjono ◽  
Chafid Fandeli ◽  
Rukmini A.R
Keyword(s):  
Power Plants ◽  
Hydroelectric Power Plant ◽  
Dry Season ◽  
Local Economy ◽  
Energy Technology ◽  
Hydroelectric Power ◽  
Central Java ◽  
Water Plants ◽  
Multipurpose Dam

<span>Hydroelectric power plants in Indonesia are widely developed. This is because the water supply in Indonesia is quite abundant. Several large reservoirs in Indonesia, in addition to being used for water reservoirs, are used to produce electricity. Wonogiri is a region that is located in Central Java province, where most of the region is arid land that cannot be planted in the dry season. In the rainy season the abundance of water plants to die and the soil is such that in the dry season crops do not grow well. Plans for the construction of Gajah Mungkur started in 1964, and it is designed to be a multipurpose dam project that aim to control floods, supply water for irrigation and hydropower in the Solo River valley. The master development plan was formulated in 1972-1974 with the help of Overseas Technical Cooperation of Japan. The results of this study include the completion of flooding problems along the Solo River, the increase in agricultural output in Winton community with irrigation facilities and good infrastructure, availability of electricity for communities around the dam and improving the local economy as the development of inland fisheries and tourism sectors.</span>

scholarly journals Flow Division Dynamics in the Mekong Delta: Application of a 1D-2D Coupled Model

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 837 ◽  
Author(s):  
Sepehr Eslami ◽  
Piet Hoekstra ◽  
Herman Kernkamp ◽  
Nam Nguyen Trung ◽  
Duc ◽  
...  
Keyword(s):  
Water Level ◽  
Irrigation System ◽  
Mekong Delta ◽  
Dry Season ◽  
Offshore Wind ◽  
Water Volume ◽  
Estuarine System ◽  
Tidal Amplitude ◽  
Tidal Dynamics ◽  
Salt Intrusion

The Mekong Delta constitutes a complicated multi-channel estuarine system, exchanging water with a delta-wide irrigation system. A 1D–2DH coupled numerical domain is calibrated and validated for water level and discharge during the dry season. This approach benefits from the simplicity of a 1D network within the estuarine and irrigation systems, while maintaining the interaction with the spatial tidal dynamics of the 2DH coastal domain. First, the role of the irrigation system on tidal dynamics is quantified; then, tidal propagation, freshwater budget, and the effect of offshore subtidal water level on discharge division are investigated. The results show that the complex irrigation system, in a friction-like manner, reduces the tidal amplitude up to 25%. The channels aggregate to 1% of the total water volume in the delta, while accommodating up to 10% of the tidal prism. Tidal amplitude reduces upstream, while subtidal water level is highly sensitive to upstream discharge, spring–neap cycles, and wind-generated offshore surge. Although cumulative discharge division within the estuarine network is consistent, temporal discharge division can be significantly sensitive to offshore wind-surge. During the dry season, it can reverse the expected subtidal discharge division within the time-scale of a few days and potentially influence salt intrusion.

scholarly journals Flooding in the Mekong Delta: Impact of dyke systems on downstream hydrodynamics

2019 ◽  
Author(s):  
Vo Quoc Thanh ◽  
Dano Roelvink ◽  
Mick van der Wegen ◽  
Johan Reyns ◽  
Herman Kernkamp ◽  
...  
Keyword(s):  
Mekong Delta ◽  
River System ◽  
Dry Season ◽  
Water Levels ◽  
Mekong River ◽  
Flood Season ◽  
Tidal Propagation ◽  
River Outflow ◽  
Year 2000

Abstract. Building high dykes is a common measure to cope with floods and plays an important role in agricultural management in the Vietnamese Mekong Delta. However, the construction of high dykes cause considerable changes in hydrodynamics of the Mekong River. Therefore, this paper aims to assess the impacts of the high dyke system on water level fluctuation and tidal propagation on the Mekong River branches using a modelling approach. In order to consider interaction between rivers and seas, an unstructured modelling grid was generated, with 1D–2D coupling, covering the Mekong Delta and extending to the East (South China Sea) and West (Gulf of Thailand) seas. The model was manually calibrated for the flood season of the year 2000. To assess the role of floodplains, scenarios consisting of high dykes built in different regions of the Long Xuyen Quadrangle (LXQ), Plains of Reeds (PoR) and TransBassac were carried out. Results show that the percentage of river outflow at Dinh An sharply increases in the dry season in comparison to the flood season while the other Mekong estuarine outflows rise slightly. In contrast, the lateral river flows of the Mekong River system to the seas by the Soai Rap mouth and the LXQ decrease somewhat in the dry season compared to the flood season due to overflow reduction at the Cambodia–Vietnam border. Additionally, the high dykes in the regions that are directly connected to a branch of the Mekong River, not only have an influence on the hydrodynamics in their own branch, but also on other branches because of the connecting channel of Vam Nao. Moreover, the high dykes built in the PoR, LXQ and TransBassac regions are the most important factor for changing water levels at Tan Chau, Chau Doc and Can Tho, respectively. The LXQ high dykes result in an increase of daily mean water levels and a decrease of tidal amplitudes on the Song Tien (downstream of the connecting channel of Vam Nao). A similar interaction is also found for the the PoR high dykes and the Song Hau.

scholarly journals Mantle-derived helium released through the Japan trench bend-faults

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin-Oh Park ◽  
Naoto Takahata ◽  
Ehsan Jamali Hondori ◽  
Asuka Yamaguchi ◽  
Takanori Kagoshima ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Large Scale ◽  
Japan Trench ◽  
Helium Isotope ◽  
Normal Faults ◽  
Circulation System ◽  
Deep Penetration ◽  
Oceanic Plate ◽  
Seismic Reflection Data ◽  
Reflection Data

AbstractPlate bending-related normal faults (i.e. bend-faults) develop at the outer trench-slope of the oceanic plate incoming into the subduction zone. Numerous geophysical studies and numerical simulations suggest that bend-faults play a key role by providing pathways for seawater to flow into the oceanic crust and the upper mantle, thereby promoting hydration of the oceanic plate. However, deep penetration of seawater along bend-faults remains controversial because fluids that have percolated down into the mantle are difficult to detect. This report presents anomalously high helium isotope (3He/4He) ratios in sediment pore water and seismic reflection data which suggest fluid infiltration into the upper mantle and subsequent outflow through bend-faults across the outer slope of the Japan trench. The 3He/4He and 4He/20Ne ratios at sites near-trench bend-faults, which are close to the isotopic ratios of bottom seawater, are almost constant with depth, supporting local seawater inflow. Our findings provide the first reported evidence for a potentially large-scale active hydrothermal circulation system through bend-faults across the Moho (crust-mantle boundary) in and out of the oceanic lithospheric mantle.

scholarly journals Analytical Approach to Sampling Estimation of Underwater Tunnels Using Mechanical Profiling Sonars

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1900
Author(s):  
Vitor Augusto Machado Jorge ◽  
Pedro Daniel de Cerqueira Gava ◽  
Juan Ramon Belchior de França Silva ◽  
Thais Mancilha ◽  
Waldir Vieira ◽  
...  
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Hydroelectric Power ◽  
Large Power ◽  
Unmanned Underwater Vehicles ◽  
Power House ◽  
Simulated Environment ◽  
Sonar Sensor ◽  
Power Plant Operation ◽  
Plant Power

Hydroelectric power plants often make use of tunnels to redirect the flow of water to the plant power house. Such tunnels are often flooded and can span considerable distances. Periodical inspections of such tunnels are highly desirable since a tunnel collapse will be catastrophic, disrupting the power plant operation. In many cases, the use of Unmanned Underwater Vehicles (UUVs) equipped with mechanical profiling sonars is a suitable and affordable way to gather data to generate 3D mapping of flooded tunnels. In this paper, we study the resolution of 3D tunnel maps generated by one or more mechanical profiling sonars working in tandem, considering synchronization and occlusion problems. The article derives the analytical equations to estimate the sampling of the underwater tunnels using mechanical profiling sonars (scanning sonars). Experiments in a simulated environment using up to four sensors simultaneously are presented. We also report experimental results obtained by a UUV inside a large power plant tunnel, together with a first map of this environment using a single sonar sensor.

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