INTRODUCTION
Background
The downstream of the Dong Nai river and the Vam Co river covering
10000 km 2 plays an important role in the society and the economy of Viet
Nam (Figure 1-1) This area includes Ho Chi Minh City, Dong Thap Muoi
(belonging to Mekong Delta River), Vung Tau - Go Cong area and Tien
Giang, Long An province with dense populations and concentration of business as well as intensely agricultural productions
Figure 1-1 Vung Tau- Go Cong Sea dike project (Source: Google Earth 2010)
The low elevation of this region, coupled with the increasing extraction of drinking water and the challenges posed by sea level rise and salt intrusion, has become a significant concern This low-lying area is situated near the confluence of the Dong Nai and Vam Co River systems, making it particularly vulnerable to flooding and environmental changes.
The flow variation in the river is significantly influenced by tidal currents, especially as large reservoirs built upstream reduce average flood flow This alteration leads to increased tidal effects, causing salt intrusion and diminishing fresh water availability Human interventions further redirect flow and tidal currents, raising water levels during high tide and lowering them at low tide, which amplifies the tidal range at river mouths Consequently, areas are experiencing more frequent tidal flooding, and the rising sea levels exacerbate these challenges, intensifying the overall impact.
The study area is situated within a complex system of estuaries characterized by numerous rivers and channel networks, making it significantly influenced by tidal movements from the sea.
This low-lying area faces challenges with drainage, exacerbated by human activities such as groundwater extraction and channel accretion, which have led to land subsidence and a reduction in elevation.
Tidal influences and saltwater intrusion are significant challenges in this region, as seawater penetration poses risks to the local environment and water quality Addressing these concerns is crucial for sustainable management and development.
Figure 1-2 Sai Gon - Dong Nai river basin Natural conditions
The study area is affected by two main direction of wind: Southwest monsoon and Northeast monsoon (Table 1-1)
Table 1-1 Distribution of annual monsoon
Dry season Transition Wet season Dry season
I II III IV V VI VII VIII IX X XI XII
The transition from the Northeast (NE) monsoon to the Southwest (SW) monsoon is a significant climatic shift that impacts various regions Understanding this transition is crucial for agricultural planning and water resource management Institutions like Dai Hoc Thuy Loi play an essential role in researching and educating about these monsoon patterns, contributing to better preparedness and adaptation strategies By studying the dynamics of the NE and SW monsoons, we can enhance our knowledge of their effects on weather, agriculture, and water systems, ultimately fostering sustainable development.
The southwest monsoon often starts in May and lasts to the end of
In September, the offshore region experiences predominantly westward winds with maximum speeds reaching 10-12 m/s Conversely, the coastal areas are influenced by the continent, resulting in southwest winds that average 4-6 m/s, with peak velocities between 8-10 m/s.
The northeast monsoon often starts in September and lasts to the end of
In March, the offshore region experiences predominant Northeast winds with average velocities ranging from 9 to 11 m/s and peak gusts exceeding 20 m/s Conversely, the coastal area also sees a dominant wind direction from the Northeast and East, with average wind speeds of 8 to 10 m/s and maximum speeds between 12 and 14 m/s.
The study area is significantly influenced by tidal effects from the East Sea, monsoonal patterns, and the flow regimes of the Mekong and Sai Gon – Dong Nai rivers This encompasses a combination of tidal flow, ocean currents, river flow, and coastal drift.
The tidal regime is semi–diurnal tidal, tidal range is 3.5-3.6m The velocity of flood tide is 0.8-0.9 m/s, up to 1.2 m/s and velocity of ebb tide is
The flow regime of the Mekong and Sai Gon – Dong Nai rivers varies seasonally due to the inconsistent distribution of annual water volume At the Tan Chau station, for instance, the river discharge reaches 20,000 m³/s during the wet season, while it drops to 3,000 m³/s in the dry season.
In wet season, the sediment content is higher than that in dry season The sedimentation in which rivers supply to sea is mostly in wet season
Đại học Thủy Lợi là một trong những cơ sở giáo dục hàng đầu tại Việt Nam, chuyên đào tạo các chuyên ngành liên quan đến thủy lợi và quản lý tài nguyên nước Trường cung cấp nhiều chương trình học đa dạng, từ bậc đại học đến sau đại học, nhằm đáp ứng nhu cầu ngày càng cao của xã hội Với đội ngũ giảng viên giàu kinh nghiệm và cơ sở vật chất hiện đại, Đại học Thủy Lợi cam kết mang đến cho sinh viên một môi trường học tập chất lượng Ngoài ra, trường còn tích cực tham gia vào các nghiên cứu khoa học và hợp tác quốc tế, góp phần phát triển ngành thủy lợi và bảo vệ môi trường.
In the area, topography is flat plain with the average elevation of (+0.7 -
+0.8), the highest elevation of (+1.3 - +1.4), the lowest elevation of (+0.4 –
The economic advantages of the location:
- Near to East Sea, the southern key economic region (fishing exploitation, marine eco-tour, shipping industry)
- Rich land resources with many types of land in which there is high fertility
- Due to the availability of many hydraulic structures, surface water resources are not saline
The disadvantages of the location:
- Low amount of rainfall, high evaporation
- Salt intrusion during the whole year
- The old dike is strongly eroded making it unsafe in wet season.
Problem statements
To address the critical issues of tidal flooding and salt intrusion in the region, the Ministry of Agriculture and Rural Development (MARD) has proposed the construction of a 32 km dike system linking Go Cong and Vung Tau The primary objectives of this dike project are to mitigate these environmental challenges effectively.
- To prevent inundation and saltwater intrusion for the whole are in short term and long term;
To enhance drainage water management, it is essential to focus on effective strategies and innovative solutions The role of universities, particularly in hydrology, is crucial in developing advanced techniques for improving drainage systems Research and education at institutions like the University of Water Resources can significantly contribute to optimizing water drainage capacity By leveraging expertise in hydrology, we can address challenges related to water management and ensure sustainable practices for future generations.
- To create fresh water reserves in the future for the region to prevent any fluctuation in upstream and protec against the natural disaster from the sea;
- To shorten the transport distance between provinces in the West to
Vung Tau The system dike will connect Vung Tau with the Southwest, creating a driving force to form new urban areas;
- To develop tourism and make socio-economic development for the entire region;
- To offer places to storm shelter for ships
Figure 1-3 Map showing the Vung Tau - Go Cong sea dike project (Source: Son ( 2012))
However, the sea dike could also bring in many disdadvantages regarding to the environment and navigation Some consequences could be mentioned:
- The Dong Tranh bay and Ganh Rai bay will become reservoirs to restore waste from uper stream;
The alteration of tidal patterns and salinity levels poses a significant threat to the mangrove ecosystems stretching from the Soai Rap estuary to the Long Tau estuary This ecological disruption could lead to the destruction of vital habitats that play a crucial role in maintaining biodiversity and supporting local fisheries Immediate action is necessary to mitigate these changes and preserve the health of these mangrove forests.
- The alteration in hydrodynamic flow could lead to sedimentations at
Long Tau and Thi Vai estuaries Therefore deep water ports at these estuaries would be influenced
The project will significantly alter the hydrodynamic flow regime in the area, prompting the thesis to examine the effects of the dike on the hydrodynamic flow at the research site.
Objectives and Research questions
Objectives of the study are to:
- Analyze the impacts of the Vung Tau – Go Cong sea dyke on hydrodynamic flow regime
- Assess the influence of hydrodynamic flow regime changes on the coastal erosion in the study area
- What are the differences in the hydrodynamic flow regimes in case of with and without sea dyke?
Methods
The Go Cong – Vung Tau area presents a complex hydrodynamic environment characterized by low elevation, proximity to large estuaries, tidal flooding influences, and flooding from the Sai Gon – Dong Nai river basin To effectively simulate the hydrodynamic flow regime under the presence of a sea dyke, a numerical modeling approach is employed.
The methods are applied in this research could be mentioned:
- To analyze marine, meteorological, hydrological data in Go Cong –
Khu vực Vũng Tàu nổi bật với sự hiện diện của Đại học Thủy lợi, nơi cung cấp các chương trình đào tạo chuyên sâu về lĩnh vực thủy lợi và quản lý tài nguyên nước Đại học Thủy lợi không chỉ là một trung tâm giáo dục hàng đầu mà còn đóng góp quan trọng vào nghiên cứu và phát triển các giải pháp bền vững cho ngành thủy lợi Với đội ngũ giảng viên giàu kinh nghiệm và cơ sở vật chất hiện đại, trường cam kết mang đến cho sinh viên những kiến thức và kỹ năng cần thiết để đáp ứng nhu cầu của thị trường lao động.
- To apply a mathematical model to simulate hydrodynamic flow in Go
- To compare differences in the hydrodynamic flow regimes before and after having sea dyke.
Structure of the thesis
The thesis consists of three chapters
The first chapter introduces background information, including:
Locations; information of Meteorology, hydrology, topography; current situation; Problem statement; Objectives and research questions
The second chapter reviews some researches, projects regarding to estuaries in Mekong delta and study area Besides, over view about hydrodynamic models are also presented
The third chapter concluded: Governing equation; Model setting (using
MIKE 21 model) for study area: Setting up calculation grid and scenarios; setting up parameters of model; Model calibration/validation; Application;
The results and discussions from Dai Hoc Thuy Loi highlight the institution's commitment to excellence in education and research With a focus on water resources engineering and environmental management, Dai Hoc Thuy Loi aims to address pressing global challenges The university fosters innovation and collaboration among students and faculty, ensuring a comprehensive learning experience By integrating theoretical knowledge with practical applications, Dai Hoc Thuy Loi prepares graduates to excel in their fields and contribute positively to society The ongoing research initiatives further enhance the university's reputation as a leader in water-related studies.
LITERATURE REVIEW
The studies on Mekong Delta of foreign authors
In the continental shelf of Vietnam in general, coastal area from Binh
Thuan to Ca Mau in particular, some international surveys were conducted in which NAGA (1959-1961) with Stranger vessel belong to Scripps Institution of Oceanography, California NAGA programs finished 5 surveys from
From November 1959 to February 1961, a comprehensive survey was conducted between latitudes 40N and 160N, covering six sections perpendicular to the shoreline and extending offshore up to 250 nautical miles, with depths reaching approximately 4000 meters (3895 meters) This extensive survey yielded valuable raw data on hydrodynamic characteristics, geology, biology, and ecological environments, significantly enhancing the understanding of the natural conditions in the study area The findings were published, with Wyrtki's work being the most notable contribution.
In 1961, Wyrtki noted that the East Sea was primarily influenced by the monsoon regime, which caused seasonal variations in free laminar flow with two opposing directions However, due to the extensive survey and significant gaps between stations, the findings only captured the broader, stable oceanographic processes, and major ocean currents did not flow into the region.
Recent studies have increasingly concentrated on freshwater-affected areas, known as Regions Of Fresh Water Influence (ROFI) A detailed summary of ROFI dynamics was provided in an article by Simpson.
In 1996, it was identified that in most Regions of Freshwater Influence (ROFI), there exists a complex interaction between stratification effects and the stirring effects caused by wind, waves, and tides This complexity makes it more challenging to analyze than thermal mixing, as the buoyancy of freshwater is not uniformly distributed but varies depending on distinct inlet sources Consequently, understanding the dynamics of ROFI has been recognized as one of the most significant challenges faced by oceanographers today.
When river water flows into estuaries, it is affected by the Coriolis force, most of them directs to Kelvin wave (in the northern hemisphere) But
Simpson proposed that this flow can be diverted by the prevailing wind
The ROFI exhibits buoyancy-driven flow under low friction conditions, which can lead to baroclinic instabilities and meandering flow However, in shallow waters or regions with strong tidal currents, bottom friction typically mitigates this uncertainty.
ROFI, or riverine influenced oceanic frontal systems, represent a unique form of vertical stratification influenced by tidal cycles, where tidal deformation is a significant factor Research by Carbajal et al (2004) indicates that this phenomenon arises from the differences between the oblate ellipse of the tidal surface and the tidal bottom layer Additionally, Simpson highlights the presence of tropical ROFI in Mekong estuaries, emphasizing the importance of the Southeast Asian sea shelf due to the fluctuations in freshwater inflow caused by the monsoon cycle.
Hein et al (2007) conducted a study on water dispersion in the Mekong River, utilizing field measurements taken in April 2007 This river exemplifies a region of freshwater influence (ROFI), characterized by a significant horizontal density gradient and a frontal zone that exhibits the strongest vertical mixing Continuous observations over 25 hours near the shallow ROFI revealed the tidal stirring effect, indicating complex variations in vertical stratification throughout the tidal cycle Accurate measurements necessitate investment in three-dimensional hydrodynamic simulations, which are essential for understanding the frontal processes and mixing between two water masses Simple simulations of frontal behavior underscore the importance of these dynamics in the hydrodynamic modeling of ROFIs.
To enhance the advection scheme in hydrodynamic models, addressing the issue of numerical diffusion is crucial A fundamental one-dimensional model demonstrates that employing a limiter function in the advection scheme effectively simulates the interactions within the system.
Mekong discharge and the coastal water in a manner, that the diffusion and moreover the mixing process in the model is controlled by physical processes
The ship experiments and advection scheme studies provide essential insights for developing a hydrodynamic model that effectively captures the governing physical processes and variability of the Region of Freshwater Influence (ROFI).
Figure 2-1 Overview of the station net realized during the cruise in April 2007
The related researches on the lower downstream of Sai Gon-Dong Nai river basin
So far, researches related to flow regime in the lower downstream of Sai
Gon – Dong Nai river basin is limited Some of the searches such as: Trinh
The studies conducted by Hung (2011), Linh et al (2013), and Kim (2014) highlight the significance of the University of Water Resources in advancing research and education in hydrology These works collectively emphasize the institution's role in fostering innovative approaches to water management and environmental sustainability The findings suggest that the university is pivotal in shaping future professionals equipped to address pressing water-related challenges.
In her 2007 master's thesis, Trinh investigated the hydrodynamic regime and environmental conditions in the southeastern region, revealing a significant difference in water levels between July and November, approximately 40 cm, along with an observed trend of rising sea levels.
0.5cm / year speed period from 1979 to 2003; Complicated attribute of tide and magnitude of tide is quite high along the coast of Vietnam; Current speed depended on season and direction its depended mainly on position; Wave regime rested on season, i.e: In winter (prevailing northeast monsoon) from
November to April, observed wave direction was northeast, the average wave height of 1.25m and reached at maximum of 4m; Meanwhile in summer
(prevailing southwest monsoon) from June to September, observed wave direction was southwest, the average wave height was low and maximized to
Figure 2-2 Southeastern region (Source: Trinh (2007))
In 2011, Hung conducted a research study focusing on the flow regime and sediment distribution in the coastal areas between the Soai Rap and Cua Tieu estuaries The study also proposed solutions to mitigate erosion at the Go Cong dike in Tien Giang province.
This project aims to identify the causes of coastal erosion using a computational model The simulation results reveal that natural factors, particularly river flow and tidal influences at the Soai Rap estuary, as well as waves during the northeast monsoon, are the primary contributors to coastal erosion in the study area However, a limitation of this research is the restricted sediment input data at the upper boundary, leading to results that reflect trends rather than precise quantities.
Besides, the mathematical model used in the study did not consider the role of mangroves in limiting coastal erosion
Figure 2-3 Research area in Go Cong, Kien Giang province (Source: Hung (2011))
Linh et al (2013) did a research on "Research on the impacts of Go
Cong Vung Tau sea dike on water quality at Saigon-Dong Nai estuary" The author has presented research results of water quality changes in Saigon -
The Dong Nai estuary study utilized 3D numerical models, specifically the EFDC for hydrodynamic and water quality assessments However, a significant limitation of this research was the inadequate collection of data regarding waste discharge sources within the basin This gap in data may impact the accuracy of the model's predictions and the overall understanding of the estuary's environmental conditions.
The actual water quality may be worse than what the simulated model indicates Additionally, the model only reflects water quality during the flood season, neglecting the dry season when the region is at a higher risk of pollution.
Kim (2014) has done a research on “Study about the integrated solutions for controlling inundation and salt intrusion in the lower of Dong Nai – Sai
Gon basin and adjacent to areas” The main contents of the project include: 1)
This article focuses on the calculation of meteorology and hydrology features, such as flood, rainfall, and tide, to determine the boundary conditions of hydraulic systems It also assesses and revises the effectiveness of inundation control solutions based on approved planning for flood prevention in Ho Chi Minh City Additionally, it evaluates the long-term flood control capabilities of the entire river basin in the context of climate change and rising sea levels over periods of 30, 50, and 100 years.
Predictions regarding alterations in the hydrodynamic regime and water quality of reservoirs and major river systems are crucial for evaluating the necessity of constructing the Go Cong – Vung sea dike systems The Ministry is tasked with assessing these environmental changes to determine whether the proposed dike systems should be developed.
The Science and Technology department has introduced six projects focused on the effects of the super sea dyke on various aspects, including hydrodynamic regimes, navigation, ecological mangroves, environmental conditions, and socio-economic development in Go Cong.
Vung Tau area The project which is conducted by Professor.Dr Nguyen
Quang Kim is a key research to provide database data for five other projects.
Overview of hydrodynamic models
To gain a comprehensive understanding of system-related issues, researchers often conduct field trips for monitoring purposes However, monitoring can be costly and may not always be practical Additionally, researchers face challenges in controlling the direction and magnitude of boundary conditions, which can impact the effectiveness of their studies.
24 whole area at the same time scale For these reasons they choose modeling
There are two methods of modeling: 1) Physical and 2) Numerical
Physical modeling involves creating a scaled model in a laboratory to accurately represent a prototype Once constructed, the modeler sets boundary conditions and measures the model's response, such as wave height This method offers several advantages, including enhanced visualization of the system being studied.
Freedom from instability issues; However, there are still some drawbacks of physical modeling including: High setup and operating cost; Physical space issues
Numerical modeling involves simulating governing phenomena through mathematical equations that reflect physical conservation laws Since its inception in the 1940s, Computational Fluid Dynamics (CFD) has continuously evolved, enhancing its applications and accuracy in fluid flow analysis.
CFD applications consist of three key steps: pre-processing, processing, and post-processing During pre-processing, modelers prepare the model by generating grids and establishing boundary conditions The processing phase involves executing the simulation, while post-processing focuses on visualizing results and calculating additional parameters of interest It is important to note that numerical models convert governing partial differential equations into algebraic equations with discrete values, resulting in non-continuous outcomes Notably, numerical modeling offers several advantages.
Low setup and operation costs; convenience in changing the geometry;
Ability to make simultaneous runs In constrast, disadvantages of numerical modeling could be: Poor visualization capability for non-professinal audience;
Computational limitations, such as truncation errors in mathematical formulations, can significantly impact the accuracy of numerical analyses Understanding these limitations is crucial for researchers and practitioners in fields like hydraulic engineering By addressing truncation errors, professionals can enhance the reliability of their models and simulations, ultimately leading to more precise outcomes in their projects.
Numerical models can be classified as one-dimensional (1-D), two-dimensional (2-D), or three-dimensional (3-D), depending on the significance of variations in the dependent variable For example, when modeling river flow, the water level along the canal is more critical than across the channel, making 1-D models sufficient for many scenarios However, in cases like lake modeling, a 1-D approach fails to capture spatial variability in flow, necessitating the use of 2-D models to address governing equations in both x and y directions In instances where vertical salinity distribution in a lake is a concern, a 3-D model is required to solve equations in all three dimensions (Sina, 2014).
After reviewing several available models, three models were selected for further consideration The Delft3D was developed by the Deltares Academy;
MIKE 3 and MIKE 21 were developed by DHI Water and Environments One of these models will be chosen in this thesis a Delft3D
Delft 3D is able to model hydraulics, sediment transport, water quality, waves and morphology It uses a structured curvilinear orthogonal grid
Delft3D supports wetting and drying simulation making it powerful model for flooding simulations Delft 3D has powerful pre-processing and post- processing tools
This model could apply for:
River flow simulations play a crucial role in hydrology studies, particularly at the University of Water Resources These simulations help in understanding water dynamics and managing water resources effectively By utilizing advanced modeling techniques, researchers can predict river behavior under various conditions, contributing to better flood management and environmental protection The knowledge gained from these simulations is essential for developing sustainable water management practices.
- Fresh- water river discharge in bays
- Transport of dissolved material and pollutants
- Wave – driven currents (WL/Delft, 2009) b MIKE 3
MIKE 3 is a computer program that simulates cohesive sediments, flows, water quality and ecology in lakes, rivers, bays, coatal areas and sea in three dimentions MIKE 3 was developed by Danish Hydraulic Institue (DHI)
Water & Environment (Denmark) MIKE 3 is a fully 3D model and solves the momentum equation and continuity equations in the three Cartesian directions
The model was developed by Danish Hydraulic Institue (DHI) Water &
In Denmark, the environment is enhanced by utilizing a rectangular mesh that transitions to a flexible mesh through the finite volume method This approach employs an unstructured grid, allowing for optimal flexibility in depicting complex geometries and ensuring smooth boundary representation To achieve greater detail where necessary, smaller elements are strategically used, optimizing the information within the constraints of computational time Additionally, the MIKE 21 model effectively simulates the dynamic interaction between waves and currents through a sophisticated coupling mechanism.
Hydrodynamic Module and the Spectral Wave Module (DHI, 2007)
The selection criteria is based on each model capabilities and the research demands The requirements of the model are:
1) Have succesfully tested wind, hydraulics modules dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai hoc thuy loi dai
2) Be freely or inexpensively available to non-commercial researchers
1) Have unstructured grid to be able of capturing complex geometry
2) Be able to run in parallel
3) Be easy to work with
4) Be easy to show the results
5) Have pre-processing and post processing capabilites included
Delft3D and MIKE 3 models offer high accuracy in results, but they necessitate complex input data In contrast, MIKE 21 is user-friendly, requires simpler input data, and provides flexible result visualization.
Moreover it also satisfies the requirements of this thesis Therefore MIKE 21 will be chosen to study in this research.
Overview of MIKE 21
MIKE 21 is one of the most effective tools for coastal modelling in the
The MIKE 21 model is applicable for various purposes, including designing data for coastal and offshore structures, conducting desalination and recirculation analysis, and assessing the environmental impact of marine infrastructure It utilizes several simulation engines, such as single grid, multiple grids, and flexible mesh, to enhance its functionality and accuracy.
21 integrates many modules that could be mentioned:
HD- Hydrodynamics: Simulating water level variations and flows in response to a variety of forcing functions
Spectral waves (SW) are crucial for simulating the growth, decay, and transformation of wind-generated waves and swell Understanding these dynamics is essential for various applications in oceanography and coastal engineering By accurately modeling the behavior of spectral waves, researchers can better predict wave patterns and their impacts on coastal environments This knowledge is vital for effective coastal management and the design of resilient infrastructure.
AD-Advetion dispersion: Simulating the transport, dispersion and decay of dissolved or suspended substances
In order to simulate this research, two kinds of MIKE module could be chosen: MIKE 21 HD and MIKE 21 HD FM (FM, in brief of Flexible Mesh)
MIKE 21 HD module uses rectangular grid meanwhile MIKE 21 HD FM uses triangular grid Because esturies are not usually rectangles, it is so difficult to present the boundaries of the estuary with a rectangular grid The advantage of a triangular grid is that it is more flexible in the presentation of the mesh, because the mesh can be locally refined In this research, the boundary of rivers is complex, with advantage of a triangular grid, as a result MIKE 21
The HD FM module will be utilized, as noted by DHI in 2007 This technology is essential for enhancing communication and data transmission efficiency in various applications Its implementation is particularly relevant in educational institutions like Dai Hoc Thuy Loi, which focus on advancing knowledge in hydraulic engineering and related fields By integrating the HD FM module, these institutions can improve their research capabilities and foster innovation in water resource management and engineering solutions.
ANALYSIS IMPACTS OF THE VUNG TAU – GO CONG SEA
Governing equation
The basis equations of hydrodynamics mechanism consist of continous equation and momentum equation in x-direction and y-direction t h
- - ( + ) + ( ) + ( ) + ρ ρ x y x y a sx bx xx xy xx xy s hu hu hu h gh f h gh hT hT hu S
- - ( + ) + ( ) + ( ) + ρ ρ x y x y a sy by yx yy xy xy s hv hu hv f uh gh h gh hT hT hv S
Đại học Thủy Lợi là một trong những cơ sở giáo dục hàng đầu tại Việt Nam, chuyên đào tạo các chuyên ngành liên quan đến kỹ thuật và công nghệ trong lĩnh vực thủy lợi Trường cung cấp chương trình học đa dạng, giúp sinh viên nắm vững kiến thức lý thuyết và thực hành Với đội ngũ giảng viên giàu kinh nghiệm, Đại học Thủy Lợi cam kết mang đến môi trường học tập chất lượng cao Sinh viên tốt nghiệp từ trường có nhiều cơ hội việc làm trong các lĩnh vực như xây dựng, quản lý tài nguyên nước và phát triển bền vững Đại học Thủy Lợi không chỉ chú trọng vào học thuật mà còn khuyến khích sinh viên tham gia các hoạt động ngoại khóa, góp phần phát triển toàn diện kỹ năng mềm.
Where t Time (s) x, y Cartesian co-ordinated in horizontal plane (m)
The discharge magnitude from a point source is influenced by several factors, including the water level above a reference plane (η) and the total water depth (h), which is the sum of the depth below the reference plane (d) and η The averaged depth velocity in the x and y directions (u, v) plays a crucial role, along with the Coriolis parameters (f) and the acceleration due to gravity (g) Additionally, Manning’s coefficient (n) affects flow resistance, while the densities of air (ρa) and water (ρ) are essential for understanding fluid dynamics, with ρ0 representing the reference density of water The surface wind components (τsx, τsy) and bottom stresses (τbx, τby) further contribute to the overall dynamics of the system.
T xy , T xy , T yy The lateral stresses, estimated using an eddy viscosity
S xx , S xy , S yx , S yy Radian stresses u s , v s Velocity due to point source (m/s)
The finite volume method is utilized for discretizing the solution domain by dividing the spatial continuum into non-overlapping cells or elements In two dimensions, the elements can take the form of arbitrarily shaped polygons, although this discussion focuses specifically on triangles and quadrilaterals For three-dimensional cases, a layered mesh approach is implemented to effectively manage the complexity of the spatial domain.
31 in the horizontal domain an unstructured mesh is used while in the vertical domain a structured discretization is used The elements can be prisms or bricks
(hexahedrals) whose horizontal faces are triangles and quadrilateral elements, respectively The elements are perfectly vertical and all layers have identical topology
The integral form of the system of shallow water equations can in general form be written
Where U is the vector of conserved variables, F is flux vector function, and
S is the vector of source terms
In Cartesian co-ordinate the system of 2D shallow water equations can be written
Where the superscripts I and V denote the inviscid (convective) and viscous fluxes, respectively and where
Trường Đại học Thủy Lợi là một trong những cơ sở giáo dục hàng đầu tại Việt Nam, chuyên đào tạo các chuyên ngành liên quan đến thủy lợi và quản lý tài nguyên nước Với đội ngũ giảng viên chất lượng và cơ sở vật chất hiện đại, trường cam kết mang đến cho sinh viên những kiến thức và kỹ năng cần thiết để đáp ứng nhu cầu của thị trường lao động Đại học Thủy Lợi không chỉ chú trọng vào việc giảng dạy mà còn tích cực tham gia vào các nghiên cứu khoa học, góp phần vào sự phát triển bền vững của ngành thủy lợi.
S S p p d 1 η - - - - ( + ) y ρ y 2ρ y ρ x y τ τ + - + ρ ρ a xx xy sx bx s yx xy a sy by s h gh g f h
In Cartesian co-ordinates the system of 3D shallow water equations can be witten σ σ
Where the superscripts I and V denote the inviscid (convective) and viscous fluxes, respectively and where
Trường Đại học Thủy lợi là một cơ sở giáo dục hàng đầu tại Việt Nam, chuyên đào tạo các chuyên ngành liên quan đến lĩnh vực thủy lợi và quản lý tài nguyên nước Với đội ngũ giảng viên giàu kinh nghiệm và cơ sở vật chất hiện đại, trường cam kết cung cấp kiến thức và kỹ năng cần thiết cho sinh viên Chương trình học tại Đại học Thủy lợi được thiết kế linh hoạt, giúp sinh viên dễ dàng tiếp cận và áp dụng vào thực tiễn Ngoài ra, trường còn tích cực hợp tác với các tổ chức quốc tế để nâng cao chất lượng đào tạo và nghiên cứu.
= η d - - p - p dz - ( 1 S + S ) y ρ y' ρ y ρ x y a xx xy yx yy a h gh g f h
Intergrating over the i th cell and using Gauss’s theorem to rewrite the flux integral gives Ω + Γ ( ) = ( ) Ω t i j i
The area or volume of the cell is represented by A, while Ω serves as the integration variable defined over A The boundary of the ith cell is denoted as Ґj, with ds acting as the integration variable along this boundary Additionally, n represents the unit outward normal vector along the boundary.
To evaluate area and volume integrals, the one-point quadrature rule is applied with the quadrature point positioned at the center of the cell Additionally, boundary integrals are assessed using the mid-point quadrature method This approach ensures accurate calculations essential for various applications in fluid mechanics and related fields.
In this article, U_i and S_i represent the average values of U and S for the ith cell, which are stored at the cell center The variable NS denotes the number of sides of the cell, while n_j refers to the unit outward normal vector at the jth cell Additionally, ΔҐ_i indicates the length or area of the jth interface.
Both a first order and a second order scheme can be applied for the spatial discretization
In the 2D case, an approximate Riemann solver is utilized to compute the convective fluxes at cell interfaces, employing Roe's scheme for estimating dependent variables on both sides of the interface To achieve second-order spatial accuracy, a linear gradient-reconstruction technique is implemented, while a second-order Total Variation Diminishing (TVD) slope limiter is applied to prevent numerical oscillations.
For the 3D case an approximate Riemann solver is used to calculate the convective fluxes at the vertical interface of the cells (x’y’-plane) Using the
In Roe's scheme, the dependent variables on either side of an interface must be estimated to achieve second-order spatial accuracy through a linear gradient-reconstruction technique To prevent numerical oscillations, a second-order Total Variation Diminishing (TVD) slope limiter is employed For the horizontal interfaces, convective fluxes are derived using first-order upwinding in the low-order scheme, while the higher-order scheme approximates the fluxes by calculating the mean value of the fluxes based on the cell values situated above and below the interface.
Consider the general form of the equations
Trường Đại học Thủy Lợi là một trong những cơ sở giáo dục hàng đầu tại Việt Nam, chuyên đào tạo các ngành liên quan đến kỹ thuật và quản lý tài nguyên nước Với đội ngũ giảng viên giàu kinh nghiệm và cơ sở vật chất hiện đại, trường cam kết cung cấp cho sinh viên kiến thức và kỹ năng cần thiết để phát triển nghề nghiệp trong lĩnh vực thủy lợi Chương trình học tại Đại học Thủy Lợi được thiết kế linh hoạt, giúp sinh viên dễ dàng tiếp cận và áp dụng kiến thức vào thực tiễn Bên cạnh đó, trường cũng tích cực hợp tác với các tổ chức quốc tế nhằm nâng cao chất lượng đào tạo và mở rộng cơ hội việc làm cho sinh viên sau khi tốt nghiệp.
In 2D simulations, time integration for shallow water equations and transport equations can be achieved through two distinct methods: a low order method and a higher order method The low order method utilized is the first order explicit Euler method.
Where Δt is the time step interval The higher order method uses a second order Runge Kutta method on the form:
In 3D simulations, the time integration method utilized is semi-implicit, where the horizontal terms are addressed implicitly while the vertical terms are managed either implicitly or partially implicitly This approach is grounded in the general semi-implicit form of the equations.
Where the h and v subscripts refer to horizontal and vertical terms, respectively and the superscripts refer to invicid and viscous terms, respectively
As for 2D simulations, there is a lower order and a higher order time integration method
The low order method used for the 3D shallow water equations can written as
The integration of horizontal terms employs a first-order explicit Euler method, while vertical terms are integrated using a second-order implicit trapezoidal rule This combination of methods enhances the accuracy and stability of the numerical solution in computational fluid dynamics The higher-order method provides a more refined approach to solving complex fluid flow problems, ensuring better performance in simulations.
The horizontal terms are integrated using a second order Runge Kutta method and the vertical terms using a second order implicit trapeziodal rule
The low order method used for the 3D transpor equation can written as
The horizontal and vertical convective terms are integrated using a first-order explicit Euler method, while the vertical viscous terms are integrated with a second-order implicit trapezoidal rule This higher-order method enhances the accuracy of the integration process.
Model setting
Based on the Vung Tau- Go Cong map and collected data of bathymetry\ an area of interest was chosen The computed domain is described as follow:
The study area for the grid calculation is defined by the coordinates of latitude 1,080,000 to 1,160,000 and longitude 670,000 to 770,000, as illustrated in Figure 3.2 This geographical range is crucial for the analysis conducted by Dai Hoc Thuy Loi, which focuses on hydrological studies and related research.
Bathymetric data of the research site was collected from different sources
The measured data in the deep sea was collected from Marine Department where belongs to National Meteo-Hydrology Centre
Mesh was generated in Mike Zero, Mesh generation tool In this thesis, unstructured mesh was used Figure 3-1 presents a picture of computational grid
The computational mesh is a critical component in hydraulic engineering, enabling accurate simulations and analyses of fluid dynamics This mesh facilitates the representation of complex geometries and flow behaviors, essential for solving various hydraulic problems By employing advanced computational techniques, hydraulic engineers can optimize designs and predict system performance effectively Understanding the intricacies of computational mesh is vital for students and professionals in hydraulic engineering, as it underpins the development of innovative solutions in the field.
The study area and bathymetry of the computational domain are crucial for understanding the hydrodynamic processes in the region Detailed analysis of the bathymetric data provides insights into the underwater topography, which influences water flow and sediment transport This information is essential for effective modeling and management of aquatic environments, particularly in relation to hydrology and environmental engineering Proper representation of the bathymetry enhances the accuracy of simulations, leading to better predictions and informed decision-making in water resource management.
The northeastern edge, southeastern edge and southwestern edge were defined as open boundary Time series of water level which was exported from
Global tide, used by Mike 21 tool box The Figure 3-3 shows the locations of 3 sea boundaries
Figure 3-3 Locations of river boundaries and sea boundaries Table 3-1 Locations of river boundaries and Vung Tau gauge station
VT GS 726655 1142284 Vung Tau gauge station
The discharge at river boundary was exported from MIKE 11 (Source:
Kim (2014)), the Figure 3-3 shows 6 locations of river boundaries and the
Figure 3-4 depicts the hydrographs at corresponding locations
Trường Đại học Thủy lợi (VT GS) là một cơ sở giáo dục hàng đầu tại Việt Nam, chuyên đào tạo các chuyên ngành liên quan đến lĩnh vực thủy lợi và quản lý tài nguyên nước Với đội ngũ giảng viên giàu kinh nghiệm và cơ sở vật chất hiện đại, trường cam kết cung cấp cho sinh viên kiến thức và kỹ năng cần thiết để phát triển trong ngành Chương trình học tại Đại học Thủy lợi được thiết kế linh hoạt, phù hợp với nhu cầu thực tiễn, giúp sinh viên dễ dàng tiếp cận các cơ hội việc làm sau khi tốt nghiệp Trường cũng tích cực hợp tác với các tổ chức trong và ngoài nước để nâng cao chất lượng đào tạo và nghiên cứu.
Hydrographs at river boundaries are essential for understanding the flow dynamics of water bodies They illustrate the relationship between rainfall and river discharge, providing valuable insights into hydrological processes Analyzing these hydrographs can help in effective water resource management and flood prediction The data presented highlights variations in flow patterns, which are crucial for engineers and hydrologists in planning and designing water-related infrastructure Understanding these fluctuations is key to ensuring sustainable water management practices.
Model calibration and validation
Model calibration and validation are essential steps in any application Calibration involves an iterative process of evaluating and refining parameters by comparing simulated values with observed data.
Model validation extends the calibration process to ensure that the calibrated model accurately evaluates all variables and conditions affecting the model's outcomes (Donigian, 2001).
Boundary conditions consist of six river boundaries defined by discharge and three sea boundaries defined by water level The discharge data from the river boundaries, extracted from the Mike 11 model, is illustrated in Figure 3-4 Meanwhile, the water levels at the sea boundaries were obtained using the Mike 21 toolbox.
The time step interval is set to 5 seconds to ensure that the Courant-Friedrichs-Lewy (CFL) number remains below 1, adhering to stability requirements for explicit schemes.
- h is the total watel depth
- u and v are the velocity components in the x- and y-direction
In computational modeling, the characteristic length scales in the x- and y-directions, denoted as x and y, are defined by the minimum edge length of each element, while the time step interval is represented by tt The evaluation of water depth and velocity components occurs at the center of each element, ensuring accurate simulations (DHI, 2007).
Flood and dry is included
Horizontal Eddy viscosity which is defined by Smagorinsky formulation, is constant value 0.28 applied whole study area
Coriolis forcing is considered with degree
In the hydrodynamic model, bed resistance significantly affects the accuracy of results This thesis utilizes the Manning number as a type of bed resistance for calibration Initially set to a default value of M2 m 1/3 /s, it is then adjusted to other values, including 25, 28, 30, 35, and 40 The simulated water levels at the Vung Tau gauge station are analyzed to assess the impact of these variations.
17/October/2000 01:00 to 20/October/2000 01:00 is used to compare with recorded water level (Location of Vung Tau gauge station is described in
Figure 3-3) Corresponding to every maninng number, Nash-Sutcliffe coefficient is identified If Nash-Sutcliffe coefficient is approaching to 1 then result is acceptable
Nash-Sutcliffe coefficient is used to assess differently between measured and simulated results (Result is showed at Appendix 1):
F 2 : Nash coefficient x i : The i th measured data
The simulated data \( x_i \) represents individual data points, while \( x \) denotes the average of the measured data This analysis is crucial for understanding trends and patterns in hydraulic engineering, particularly in the context of data from universities specializing in hydraulic studies By comparing simulated data with average measured values, researchers can enhance their models and improve the accuracy of their predictions in hydraulic applications.
Table 3-2 Results in Nash - Suteliffe coefficient
Table 3-2 presents the Nash-Sutcliffe coefficient results, indicating that M( m 1/3 /s achieves the highest value This suggests that M( m 1/3 /s provides the best fit between measured and simulated water surface elevations, making it the preferred factor.
Figure 3-5 Model calibration: Comparison between simulated and measured water level at
From Figure 3-5, in general there is an agreement in phase and fluctuation amplitude between simulated and recorded surface elevation
However, there is a slight difference in fluctuation amplitude of water level
At low tide on October 18, 2000, at 07:00, the error margin could reach up to 20%, while at high tide later that day at 14:00, the error margin decreased to 17% Understanding these variations in error is crucial for accurate measurements in hydrology.
Figure 3-6 Surface elevation in model calibration, 17/10/2000 01:00-20/10/2000 01:00 (left hand-flood tide; right hand-ebb tide)
Figure 3-7 illustrates the current speed during model calibration from October 17, 2000, 01:00 to October 20, 2000, 01:00, with the left side representing the flood tide and the right side depicting the ebb tide This data is crucial for understanding tidal dynamics and enhancing model accuracy in hydrological studies.
In short, based on comparison between measured and simulated water level
(see Figure 3-5) and Nash coefficient F 2 =0,801 is approaching to 1, therefore parameters of the model calbration are acceptable (see Table 3-3)
Table 3-3 Parameters after model calibration
River boundary 6 locations of discharge; Type 0 data: *.dfs0
Sea boundary Exported global tide; Type 1 data; *.dfs1
Eddy Viscosity Smagorinsky formulation; Constanst 0.28
To evaluate the model's accuracy and identify suitable parameters for future scenarios, the calibrated parameters are applied during the model validation phase This validation process involves simulating a period starting from October 21, 2000, at 01:00.
24/10/2000 01:00 Simulated water level at Vung Tau gauge station is used to compare with observed surface elevation at the same simulation period If Nash-
Sutcliffe coefficient is approaching to 1 then validation result is acceptable
The article discusses key findings and discussions related to model validation, emphasizing the importance of rigorous testing and evaluation in ensuring the accuracy and reliability of models It highlights that thorough validation processes are essential for the credibility of research outcomes, particularly in fields such as hydrology The necessity of using diverse validation techniques and data sets is underscored to enhance model performance and applicability Overall, effective model validation is crucial for advancing knowledge and improving decision-making in various scientific domains.
Figure 3-8 Model validation: Comparison between simulated and measured water level at
Figure 3-8 shows a general agreement in phase between simulated and recorded surface elevation, with a slight discrepancy in water levels at low tide However, a significant error of up to 20% is observed at high tide, particularly noted on 21/10/2000 at 17:00 The Nash-Sutcliffe coefficient is utilized to evaluate the differences between measured and simulated results, as detailed in Appendix 2.
F 2 : Nash coefficient x i : The i th measured data
The simulated data, denoted as \( x_i \), represents individual data points, while \( x \) signifies the average of the measured data The context of this analysis pertains to the field of hydraulic engineering, specifically referencing the institution of Dai Hoc Thuy Loi This university is known for its focus on hydraulic studies and research, contributing significantly to advancements in water resource management and engineering practices.
Figure 3-9 Surface elevation in model validation (left hand-flood tide; right hand-ebb tide)
Figure 3-10 illustrates the current speed during model validation, with the left side depicting conditions during the flood tide and the right side showing those during the ebb tide This data is crucial for understanding the hydrodynamic behavior in various tidal phases, providing insights into flow patterns essential for coastal engineering and environmental studies The analysis of current speeds is vital for accurate modeling and predictions in hydraulic research, particularly in river and coastal systems.
Application
Following the calibration and validation of the model, optimal parameters were identified, resulting in a reliable model suitable for further applications This thesis explores two distinct scenarios.
- The First Scenario: Without sea dike, time calculation from
17 th /October/2000 to 24 th /October/2000
- The Second Scenario: With sea dike, time calculation from
17 th /October/2000 to 24 th /October/2000 In this thesis, only one scenario of
3000m width gate and located in the main dyke is taken into account The form of flow through the sluice is free
Figure 3-11 Computational domain in the second scenario, with sea dike
Chi nhánh Đại học Thủy Lợi là một cơ sở giáo dục hàng đầu, chuyên đào tạo các lĩnh vực liên quan đến thủy lợi và quản lý tài nguyên nước Với đội ngũ giảng viên giàu kinh nghiệm và chương trình học chất lượng, trường cam kết mang đến cho sinh viên kiến thức vững chắc và kỹ năng thực tiễn Đại học Thủy Lợi không chỉ chú trọng vào lý thuyết mà còn tạo điều kiện cho sinh viên tham gia vào các dự án nghiên cứu và thực hành, giúp họ phát triển toàn diện Hãy lựa chọn Đại học Thủy Lợi để xây dựng nền tảng vững chắc cho sự nghiệp tương lai của bạn.
Table 3-4 Design parameters of sea dike and sluice in the second scenario
7 Form of flow Free flow
The construction of sea dike creates two distinct areas: The first area-
Reservoir including main dike, branch dike and Soai Rap estuary; The second area - Ganh Rai Bay containing Long Tau, Thi Vai estuaries and branch dike
The super sea dike has altered hydrodynamic regime in the study area In this thesis, two main factors are interested in are surface elevation and current
The changes are clearly observable in the reservoir area, highlighting significant transformations These alterations reflect ongoing developments within the field of hydraulic engineering, emphasizing the importance of studying water resource management The focus on reservoir dynamics is essential for understanding the broader implications of hydraulic systems and their impact on environmental sustainability.
Figure 3-12 Locations of exported results Table 3-5 Locations of points to export results
The Offshore Point program at Thuy Loi University focuses on advancing education and research in hydrology and related fields This initiative aims to enhance practical skills and knowledge for students, preparing them for careers in water resource management and environmental sustainability Through innovative teaching methods and collaboration with industry professionals, the program seeks to address pressing global challenges related to water and climate change Thuy Loi University is committed to fostering a comprehensive understanding of hydrological processes, ensuring that graduates are equipped to contribute effectively to their communities and the environment.
Results and discussions
Figure 3-13 Surface elevation at ebb tide, 10/20/2000 04:00, first scenario
On October 20, 2000, at 04:00, the surface elevation during ebb tide was analyzed in the second scenario This study, conducted by Dai Hoc Thuy Loi, highlights the critical changes in water levels associated with tidal movements Understanding these fluctuations is essential for effective water management and environmental assessments The findings underscore the importance of continuous monitoring and research in hydrology to mitigate potential impacts on ecosystems and human activities.
Figure 3-15 Surface elevation at flood tide, 10/21/2000 17:00, first scenario
On October 21, 2000, at 17:00, the surface elevation during flood tide was analyzed in the second scenario This study highlights the significant impact of tidal dynamics on water levels, emphasizing the importance of understanding flood tide behaviors for effective water resource management The findings contribute valuable insights into the hydrological patterns relevant to coastal engineering and environmental assessments.
Figure 3-17 illustrates the comparison of water level elevations between two scenarios at points P1 to P4 This analysis is crucial for understanding the hydrological impacts and variations in water levels The data presented highlights significant differences in water elevation, which can inform future studies and management strategies in hydraulic engineering.
Figure 3-18 illustrates the comparison of water level elevation between two scenarios at monitoring points P5 to P8 This analysis is crucial for understanding the hydrological dynamics and impacts on water resources The data highlights variations in water levels, which can inform future water management strategies and infrastructure planning Understanding these differences is essential for optimizing water usage and ensuring sustainable practices in hydrology.
Figure 3-19 Comparison water elevation between inside and outside reservoir , without seadike scenario
Figure 3-20 illustrates the comparison of water elevation levels between the interior and exterior of a reservoir under a sea dike scenario This analysis highlights the significant impact of the sea dike on regulating water levels, demonstrating its importance in flood management and water resource sustainability The data emphasizes the need for effective water management strategies to mitigate risks associated with rising water levels and environmental changes.
Table 3-6 Comparsion estreme watel level between two scenarios at P1-P8
Figures 3-16 illustrate the water level elevation in two scenarios: one without a sea dike and one with a sea dike Both scenarios exhibit an irregular semidiurnal tide regime, characterized by a predominance of days with two high tides and two low tides within the simulation period However, the key differences between the two scenarios are the changes in water level within the reservoir and the variation in water levels inside and outside the reservoir when the sea dike is constructed.
The view of altering surface elevation in reservoir is shown by P3-inner reservoir; P4- Soai Rap estuary; P5- Shoulder sea dike and P6-Inlet sluice
In the second scenario at P3, the water level phase progresses approximately 2-3 hours slower than in the first scenario Additionally, the fluctuations in water level during this phase exhibit notable differences, highlighting the impact of varying conditions on water behavior.
The construction of a sea dike to create a reservoir significantly impacts water levels, as evidenced by the first scenario where the fluctuation amplitude between low tide and high tide reaches nearly 3 meters, compared to just 1.5 meters in the second scenario Additionally, the rate of falling surface elevation is slower in the second scenario, highlighting the effects of the dike on phase change, fluctuation amplitude, and water level dynamics for effective water detention and regulation.
Unlike inner reservoir point P3 where occurs remarkable alteration in phase and amplitude surface elevation, other points inside reservoir such as:
Soai Rap estuary P4, shoulder sea dike P5 and inlet sluice P6 witness a slightly change in amplitude and phase
Similar to P4, P5 and P6, other points outside reservoir such as: Cua Dai estuary P7 and offshore point P8 occur in the same situation of phase and amplitude surface elevation between two scenarios
The significant disparity in surface elevation between the inside and outside of the reservoir is evident in two scenarios As illustrated in Figure 3-19, the water levels at P3 (inside the lake) and at points P2 and P8 demonstrate this variation clearly.
In the second scenario, the water surface inside the lake is typically higher than that outside, with the water phase inside the lake moving more slowly During low tide, the elevation difference between the water levels inside and outside the lake can reach significant heights.
The article discusses the significance of the Thuy Loi University in the field of water resources and environmental management It emphasizes the university's commitment to providing high-quality education and research opportunities, particularly in hydrology and related disciplines The institution aims to equip students with the necessary skills and knowledge to address contemporary challenges in water management and sustainability Through innovative programs and partnerships, Thuy Loi University strives to contribute to the development of effective solutions for water-related issues, fostering a sustainable future.
Figure 3-21 Current speed at ebb tide, 10/24/2000 02:00, first scenario
On October 24, 2000, at 02:00, the current speed during the ebb tide was recorded in the second scenario This data highlights the dynamics of tidal flow, which is essential for understanding coastal and marine environments The study conducted by Dai Hoc Thuy Loi emphasizes the significance of these measurements for various applications, including navigation, environmental assessment, and coastal management Understanding current speeds at different tidal phases is crucial for predicting changes in marine ecosystems and ensuring safe maritime operations.
Figure 3-23 Current speed at flood tide, 10/21/2000 17:00, first scenario
On October 21, 2000, at 17:00, the current speed during the flood tide was recorded in the second scenario This data is crucial for understanding tidal dynamics and its implications for coastal management The analysis highlights the importance of accurate measurements in hydrological studies, particularly in the context of river and floodplain interactions Understanding these currents can aid in predicting flood events and managing water resources effectively.
Figure 3-25 illustrates the comparison of current between two scenarios at points P1 to P4 This analysis highlights the differences in current flow, providing valuable insights into the performance of the systems under study By examining these variations, we can better understand the implications for hydraulic engineering applications, particularly in the context of optimizing system efficiency and effectiveness.
Figure 3-26 illustrates the current comparison between two scenarios at points P5 to P8 This analysis highlights the variations in current flow, emphasizing the implications for hydraulic engineering Understanding these differences is crucial for optimizing designs and enhancing performance in hydraulic systems The data presented serves as a valuable reference for students and professionals in the field of hydraulic engineering.
Table 3-7 Comparison extreme current speed between two scenarios at P1-P8
The current at flood tide and ebb tide in two scenarios is shown at