OVERVIEWS OF STUDY OF STORM SURGE
Overview of study in the Worẽd eeccccccceseceeneceseeeeseeeeaeessaeeeseeeesneeaes 5
‘A researcher once said "model the phenomenon of water surges is an art” [8] Storm surge modeling is still being improved in the 2lst century and worldwide The storm caused water surges were sludied in these regions of the world with different names such as: in North America, storms appear in the Mexican Gulf and East Coast are called Hurricanes; in Europe, storm named Tropical Storms; in Asia and Oceania storms called Typhoons In the first half of the 20th century, scientists have studied storm surge by existed over time tools: from the simple experiment method based on sparse sampling of Conner [9] va Harris [10] to derivatives are a more complex analysis for the Sea-basin and storm with simple but limited practical value as the s has directed the study of the Proudman [II], Doodson [12] In the US, Congres research agency of army and Weather Bureau to conduct intensive research on storm and storm forecasting methods after tremendous damage of the eastemn coastal region in 1954 This is considered as the beginning of a systematic study of storm surges in North America [13] Before digital model is developed, storm map has been designed to forecast water levels rose whenever a typhoon landing on a shore, Author Conner and others have built a simple experience models to calculate approximately crest of water level rise then draw up the largest monitoring water levels based on pressure
‘monitoring data are at the center ofthe storm to determine how cover of water level [9]
In the world there are many studies using numerical models to simulate storm surge through that reviews potentially flooding due to water level rise by storms on coastal
‘area, Many storm surge models were used to simulate storm surge and provided high accuracy, Research of group R Christina used ADCIRC model to calculate the exest of
‘wave in storm surges and ability of coastal flooding in West Bengal and Bangladesh caused by ultra strong tropical storm Alia landed near the Sagar Islands in West Bengal border and Bangladesh coast on 25/5/2009 This is the storm has caused huge lesh.
‘damage to persons and property along the coastal belt of West Bengal and Ban
Results calculated by ADCIRC model showed the highest wave in the storm is up to 4 submerge all the rivers as Well as the inland are in water The extent of flooding are calculated via simulation models showed the storm caused flooding level inside area 1s 350m average and up to a maximum 600m in different areas in the coastal region of West Bengal and Bangladesh city [14]
Using numerical models to simulate the water surges in storms and flooding simulations by coastal storms are increasingly applied in recent global studies of simulation capabilities and highly accurate forecasts In a study entitled "Numerical Model of Storm Surge and Inundation in Bohai Bay" by the author Daming and other co-authors refers to the application of models to simulate storm surge and flooding due to the super storm caused in the Gulf of Bohai The authors used the ADI method to support 2D image simulation of storm surge in the FVM methods and models to support the level of flooding simulations in 2 eases: casel with jetties high 2m and cease 2 wihout jet “The results have identified flood map of region with two cases include jetty and no jetty Simulation results by model is verified accurate offers comparison with observed data in history and they were consistent with observed data
“The area North-East of the Arabian Sea include Gujarat coast of India and the western coast of Pakistan also is the area prone to the effects of the storm and suffered damage oflife and property by storm surges To simulate sea level and storm surge wamin contributed to the ris of flooding can occur, Indu Jain and other authors used the experimental model to calculate the water level in the big storm struck the coast Pakistan in 1999 and 2001 According to the sults calculated by the model, sea-level rise during a storm in 1999 was greater than 3.8 m compared with the observed results of the organization Unisys Weather, it was similar to hurricanes in 2001 and higher than 1,0m, However, the results of study not mentioned dimensional mode cially the case storm tide coincides with the highest but predicting hurricane surge could completely done by the model based on real time [16]
Along with the development of computer and information technology at present, research using models to forecast the impacts of sea level rise due to storm surge more popular than empirical statistical methods The authors LIU Juan, JIANG Wensheng
6 and other authors use Matlab model to simulate storm surge and ArcGIS model to determine the extent of flooding in the reseach name "A high resolution forecast model of storm surge inundation” The storm was chosen to simulate including 02 typhoons are 6903 (Viola) and 0104 (Utor) that has caused huge damage to Shantou coast. Comparing the simulation results with observed data of 2 typhoons on the ability showed high accuracy between the model and reality so that we can use the model to predict risk of flooding caused by storm surge [17]
‘The authors Jun Wang, Xu Shiyuan, Mingwu Ye, Jing Huang and ete used Mike 21 model to assess the risk of spills from the sea dyke sea dike and the effects of sea level rise, storm tide combined land subsidence in a study entitled “The MIKE Overtopping
The Application to Risk Assessment Model of Seawalls and Levees in Shanghai study sults showed that the risk of overflowing the sea dike and sea dykes from disasters combined effects of three natural hazards which are highly anticipated capability and comprehensive assessment of risks in the future to build preventable plans [I8]
Overview of study in Viet Nam and Hai Phong - 2-<<5<<<<<S2 7
In Viet Nam, the research on sea mostly focused on the tide change and storm surge phenomenon Particularly storm surge phenomenon has been studied since the 1970s of the last century, including a number of authors and their featured works such as; Programs and Tran Le Phuoc States (1969 - 1970), Nguyen Van Cu (1979), Pham Van Ninh (1982), Do Ngoc Quynh (1982), Vu Nhu Hoan (1988), Nguyen Ngoc Thuy (1989), Ta Dang Minh (1989), Le Trong Dao ( 1989), Bui Xuan Thong (1995), Nguyen Thi Vietnam Union (1996), Nguyen Vu Thang (1999), Bui Hong Long (2005), Nguyen Ky Phung (2006) ete
The first study of storm surges using statistical methods to calculate and chart surges in the position to be calculated, Recently, the research approach surges value method to simulate and calculate storm surges more widely used It can be said, the review study of storm surges in Vietnam is showed most clearly from 1984 to the present,within the framework of the state -vel 3 topics Research of author Pham Van Ninh.
The project 48.06.15 of the author Pham Van Ninh has developed a standard method
‘optimal standard use "Tidal table" with high precision in order to clearly identify the
‘movements and distribution time spatial phenomena of the storm surge This study has confirmed the phenomenon caused storm surges in Vietnam can be studied to give better results into practical applications [19] The project 48B.02.02 (1986-1990) studied the distribution characteristics of the phenomenon of rising water in time and space, location and time of the maximum current and surges the relationship between the time of the tidal surges to the challenge Practical significance of the research topic to determine the elevation of the marine construction to serve the planning for socio- economic areas of coastal [20] Research forecasts storm surges for specific (1991-
1995, subject KT.03.06, chaired by Do Ngoc Quynh) In addition, from the year 1996-
2000 state level project "Scientific basis and technical characteristics of coastal " by Pham Van Ninh and Do Ngoc Quynh have reviewed calculation of characterized in southern storm mode by additional data [21] In addition to state projects, there are
‘many other research topics such as the research of author Le Trong Dao presented idea in research storm surges by finite sment method to calculate tides and storm surges for the south china sea [22] Scientific research projects of Nguyen Vu Thang using computational models of coastal storm surges in Hai Phong which gave storm surge chart in forecast for the region [23] Overall studies of storm surge in the beginni have achieved certain accuracy, however because limitations of actual data about topography, tides and storms, especial limitations of speed of computer so mesh detail level and expansion of calculated boundaries during encounter many restrictions To overcome limitations of computer speed in simulating and calculating storm surge for small area, author Bui Xuan Thong used nested grid method in value model application to simulate storm Vietnam coastal waters has brought results quite detailed and accurate, Along with studies of storm surge by numerical models, recent studies tend to use the commercial model and open source model has already been builtin countries to apply the calculated storm surge of Viet Nam coast and provide high accuracy of results [24]
At present, the popular commercial model in the world include: MIKE model of the Danish hydraulic Institute (DH), SMS model of the U.S Navy, the Delft 3D model of
Delft, ctherlands, and a group of open source models including the POM model of Princeton University, ROMS model of Rutgers University and University of California, USA, model GHER of the University of Liege, Belgium, In this direction, a number of typical projects as research of Le Trong Dao using Delft3D models of Dutch to set up and simulation, forecasting storm surges to coastal areas of
Vi Nam The research of Nguyen The Twong, Tran Hong Lam and others in coordination between Vietnam - China on research forecasting ocean waves, storm surge by using different models such as Delft 3D Netherlands, JMA (Japan
‘Meteorological Agency storm surge model) of Japan and CTS (China typhoon Surge) of China to calculate and provide forceasting processes of form surge [25] In another research used the open source model such as Vu Thanh Ca and et al who applied and developed using POM model of the United States to apply storm surge calculations taking into account the influence of tide [26] From results of Vietnam National project KC.09.04/01-05 (2001-2005) “Short time prediction of hydrodynamic processes in EVS” then meteorological fields forecast models in 72h, in which, storm surge forecasts for entire coast of Viet Nam continue to be developed by Professor Dr
“Tran Tan Ti n project KCO8-05 [27] Also may include study of Nguyen Tho Sao in the study “Storm surge predictions for Vietnam coast by Delft3D model using from RAMS model” who used RAMS model to build an associated procedure for sults prediction of storm surges using Delft3D-FLOW model [28] The study of Bui Xuan
‘Thong used a method for determining possible maximum storm surge at a sea dike [29].
Studies of storm surge in Hai Phong city currently attracting interest of many experts expressed through many researchs of expects include: Nguyen Xuan Hien and et al have used the ADCIRC model to calculate storm sur ‘due to the typhoon Damrey on coastal estuary area of Hai Phong city in 2005 Simulation results using ADCIRC model were compared with measured data and produce results quite similar Base on results of these study that showed phenomenon of storm surges not only effect to sea dike, but also directly damage the estuary dikes, river dikes [30] Continue towards storm surge research by using models and empirical formula in coastal areas of HaiPhong city inleuding research of the authors Nguyen Xuan Hien and et al (2012) In storm and tide plus sea level rise by wave surges The results showed that the
‘magnitude of storm surge in the storm happened constituted about 16% to 18% of the
‘mean wave height offshore and contribute significantly to total sea level rise in storm, Storm surges in the largest total time period of 1000 years can be approximately 500em and potentially flooded area after dikes [31] In framework of the project
"Ass -ssment fluctuations extreme sea levels due to climate change serves marine economic strategy" belong to the program KC0923/06-10 "Marine science and technology serve sustainable development of social economy” was developed by ProfDinh Van Uu, software ADCIRC of SMS suite (using triangular mesh) was applied to calculate storm surge for North Bay area and details for Hai Phong coast 32]
Overview of research methodology and fooÌs 5555 +s<s>+<<s+ssxs 10
In general, the research methods of storm surge at the moment includes following methods:
Statistical measurement methods: This method is based on the statistical data to
‘measure the sea level in the study area and data of the storm affect at the came time.
From the st atistics that found the rules or build relationships correlation between data and storm surge in the study area Survey data in the field is essential which is used to calibrate and test the accuracy of the method However, this method can only be applied to each area of research, because every region has different natural conditions This isthe traditional method for relatively positive results The result ofthis approach is very important, it built up a database of catering for the integrated assessment of
‘water level in the sea areas of research and service to other methods
Experimental Methods: To determine the height of storm surges, often use the empirical formula is summarized from the data measured for each area In our country. on the bs of the survey the relationship between speed storm surge from 1959.
0 1970 in coastal area gave formula as follow:
Inwhich Wyay ~ Average of wind speed (m/s); Ah- Sea level rise (m)
- Formula of Karausev A.V., Labzovski N.A in standard 06.04.82 of Russia: ah = kw (2) suy d2
+ Standard 22TCN222-95 of Ministry of Transport:
Ah = kw (, )cos a d3)tư + Standard TLC-I-78 of Ministry of Agriculture & Rural Development ah 10° (2) cos aa)
Trkhich W— wind speed (ms): X- wind velocity km): He water igh ms ow —comective ratios a~ angle between coast and wind route (Degree)
Numerical method: Numerical modeling son ofthe optimal approach in he stay of hydrodynamic processes The firs characterise of the mo isthe subject of research as georapie regions, ime sale the process should simulate The second feature is the sizeof the space and site variables, The tied characterise of the model is
‘The dynamic processes cased storm surge mentioned above are describe in the shallow water equations by two-dimensional numerical models: ou, aus ou Em.
Ln car a n so act Mag FP ay + = p(h+é) vo
OF 2Œ+tÐw „ Antsy a xT ay 0 7)
1, v— average velocity compatible to axis x. el U@de us my VŒ)4z 1.8)£ Le UG@), V(2): changing velocity compatible to x, ý
TẢ, tỷ : wind stress on surface route axis x, ý tỷ = AM, WE + WP as) tỷ = AW, WEP (1.10)
@ : geographical latitude casing ~ Coriolis ratio
Currently in the world there are many application models us ng this method for calculating have results effectively due to the speed of the computer include: model MIKE, Delft 3D, POM, ROMS
Each calculation methods mentioned above have their advantages and disadvantages, method uses empirical formula and selling experience has advantage is easy to apply and fast ealeulation, however ealeulation results are too large and maybe differences compa © with measured results Theoretical calculation methods using modern computational model can calculate and foreca storm surge on a large scale (85,000 points can be calculated), but fixing ofthe input parameters such as angle ereated by perpendicular axis and wind direction a, coefficient Ky, wind momentum W, coefficient surface friction 2, water depth of area that make difference between the calculated results and actual measurement
Hai Phong is a coastal city, located on the east of the Northern coastal area, 102 km far from Ha Noi capital, with Quang Ninh provin e on the North, Hai Duong province on the West, Thai Binh province on the South and East Sea on the East The total natural area of 152,318.89 hectares (2001 statisti 9 account for 0.45% of the natural area of the country With Bach Long Vi island district in Tonkin Gulf, with coordinates of 20107135" - 20° 08'36" North latitude and 107°42'20" - 107%44’15" East longitude, Hai Phong has advantages of sea, rail, road and air, resulting in favorable exchange conditions with other provinces in the country and the nations of the world Due to the port, Hai Phong city plays tremendous role in import and export of North Vietnam, having quick access to scientific and technology achievements from abroad then spreading them all over the country Hai Phong seaport along with Cai Lan port (Quang Ninh city) with a capacity of several millions of tons create inereasingly-large- seale port clusters, contributing to the transportation of Northem goods to other regions of the country, as well as participating in transportation of transiting goods for
Southwest China region Along with the economical and commercial development social and cultural development of the region is oriented to development of Hai Phong City in 2025, Currently the region isa bridge between the other economic centers and
Do Son tourist center In the future, there will be more strategic projects for the economical and political development of the region Land area is divided by the rivers into five separate irrigation systems: Vinh Bao; Tien Lang; Red stones; An Duong and
‘Thuy Nguyen The whole area is located in the downstream of Thai Binh river, an important part of North Delta and is one of the main drainage direction of Red River and Thai Binh river Upstream flooding, heavy rain in the midlands and plain; tides,
‘waves and storm surges from the sea passing through the estuary are the factors causing flooding in areas, severely affected agricultural production and people's life In recent years, together with the strong development of people's livelihood, infrastructure, economy, shoreline areas were leveled out to pave for the development of infrastructure, tourism, aquaculture resulting in increasing threat of natural disasters to people's safety in coastal areas.
To deal with storms and prevent flood, Hai Phong has built dyke system consists of 24 dikes with a total length of 420.824km In which there are 18 river dikes with 314.789km long and 6 sea dykes with 106,035km, There are also 387 culverts under sea dike and 52 dams to ensure drainage and sea dike protection.
‘The subregion including Kien Thuy District, Duong Kinh and Do Son District is protected by sea dikes I and Il, being concentrated residential and economic-developed areas of Hai Phong City In whic, Do Son is a district of Hai Phong city, about 20 kilometers far from the city center to the southeast, being a small peninsula ereated by Rong Mountains spreading to the sea to 5 km, with dozens of hills from 25m to 130m high Do Son district was established on September 12, 2007 on the basis of the entire area of the former Do Son town under Decree 145/2007/ND-CP of the Socialist Republic of Vietnam Government To the west and northwest, Do Son District is next to Kien Thuy district, the remaining direction adjacent to the Bast sea, Thanks to (wo estuaries Lach Tray and Van Ue of Thai Bink river system in the north and south of the district flowing into the sea bringing a lot of sil, together with Iuxury resort on the sea dykes Hon Dau Island, the area is very attractive to the tourists Kien Thuy is a suburban district located on the southeast of the city, having a natural area of 102.56 km, with a population of over 125 thousand people Norther and eastern borders are
Do Son and Duong Kinh district, the southern is Tien Lang district and the western are Kien An and An Lao district Besides the advantage tourism with Do Son beach, the subregion including three districts also has important role in economical development, fis ing and aquaculture seafood, domestic and international trade Therefore, the role of sea dikes | and 2 to protect this sub-region are identified by Hai Phong City People’s Committee as extremely important for people's lives and social economy of the city
Topographic characteristics cccccccccesccesceeseeseeeneeeseeseeeseceseeseenseenseensenaes 15
‘The topography of Hai Phong city is quite diverse, the northern part is similar to a midland with plains interspersed with mountains while in the southern part ofthe city is relatively flat and low Hills and mountains account for 15% of the city area, more than half concentrating in the northern part of the city with northwest ~ southeast direction Hai Phong land area is divided into 5 major rivers irrigation system separately: Thuy Nguyen, Hai An, Da, Tien Lang and Vinh Bao In which, Thuy Nguyen, Hai An, Da Do have alternating hills and the plains The main slope of the terrain is from northwest to southeast Altitude is classified into the following
Overall, the cultivation of land is relatively flat, Particularly, some low-lying areas (altitude 3: Diumal: 1 High, 1 Low per day;
0.25