scholarly journals A DISPERSIVE LONG-WAVE MODEL FOR PREDICTING COASTAL FLOODING DUE TO STORM SURGES AND SURFACE WAVES IN MANILA BAY

2021 ◽  
Author(s):  
Paul C. Rivera
Keyword(s):  
Urban Areas ◽  
Storm Surges ◽  
Wave Model ◽  
Coastal Flooding ◽  
The Philippines ◽  
Coastal Areas ◽  
Momentum Balance ◽  
Long Wave ◽  
Metro Manila ◽  
Manila Bay

Manila Bay is a shallow coastal water encompassing the urban areas of Metro Manila and variouscities of sub-urban provinces in the Philippines. It is a relatively shallow semi-enclosed basinwith an average depth of 20 m whose coastal areas are crowded with residential, industrial,agricultural, and aquaculture production. Its shallow depths imply that the effect of wind stress onsea level becomes appreciable in driving storm surges even during enhanced Southwest Monsoonand the passage of moderate storms.Using a dispersive long-wave model coupled with the significant wave model of the CoastalEngineering Research Center (CERC), the occurrence of potentially devastating storm surgeflooding around Manila Bay was numerically simulated. A unique characteristic of the new modelis the inclusion of the dispersive terms in the associated momentum balance equations. Deepwater gravity waves are always dispersive and inclusion of the dispersive terms is expected toprovide more accurate modelling results.The predictive capability of the model was verified using observations during the passage ofseveral storms including Typhoon Milenyo (2006) and Typhoon Pedring (2011). The occurrenceof the anomalously high storm surge of about 2.5 metres during the passage of Typhoon Pedringfar north of the area was correctly simulated. Numerical integration of the dispersive long-wavemodel with the addition of higher order terms in the momentum balance appears to give accuratepredictions of the coastal flooding due to storm surges and waves.The hydrodynamic set-down which occurs in many coastal areas during strong typhoons can besimulated well by the model. A new empirical model for the hydrodynamic force exerted by thecombined action of storm surges, waves, and extreme currents is also presented. Initial calculationsof hydrodydynamic forces generated by an actual typhoon crossing Manila Bay are discussed.

Coastal Flood Responses in Manila Bay, the Philippines

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Dimas Fauzi
Keyword(s):  
Coastal Flooding ◽  
The Philippines ◽  
Policy Options ◽  
Groundwater Extraction ◽  
Coastal Flood ◽  
Metro Manila ◽  
Manila Bay ◽  
Coastal Floods ◽  
The Government

In 2011, Sitio Pariahan in the northern part of Metro Manila, the Philippines’ capital region, was submerged after Typhoon Nesat hit the country. In fact, Sitio Pariahan is not the only one. Many parts of Manila Bay have slowly been sinking, causing the populations to be prone to coastal floods. According to the existing studies, coastal floods in Manila Bay areas are caused by climate-induced sea-level rise and land subsidence due to the excessive groundwater extraction and rapid urban development. However, it appears that the policies implemented by the government tend to be infrastructural, for example, dike construction, which could provide immediate protection but do not really solve the problem. This case study, therefore, presents a detailed account of coastal flooding in Manila Bay, particularly on its causes and policy options to address it. More specifically, it introduces the application of social contract to understand how the terms and conditions governing the state-citizens relations in the Philippines affect government’s rationale in choosing policy options to solve the coastal flood problem.

Coastal flooding in the Balearic Islands during the 21st century caused by sea level rise and extreme events

2020 ◽  
Author(s):  
Pau Luque Lozano ◽  
Lluís Gómez-Pujol ◽  
Marta Marcos ◽  
Alejandro Orfila
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
21St Century ◽  
Extreme Events ◽  
Storm Surges ◽  
Coastal Flooding ◽  
Coastal Areas ◽  
Balearic Islands ◽  
Mean Sea Level

<p>Sea-level rise induces a permanent loss of land with widespread ecological and economic impacts, most evident in urban and densely populated areas. The eventual coastline retreat combined with the action of waves and storm surges will end in more severe damages over coastal areas. These effects are expected to be particularly significant over islands, where coastal zones represent a relatively larger area vulnerable to marine hazards.</p><p>Managing coastal flood risk at regional scales requires a prioritization of resources and socioeconomic activities along the coast. Stakeholders, such as regional authorities, coastal managers and private companies, need tools that help to address the evaluation of coastal risks and criteria to support decision-makers to clarify priorities and critical sites. For this reason, the regional Government of the Balearic Islands (Spain) in association with the Spanish Ministry of Agriculture, Fisheries and Environment has launched the Plan for Climate Change Coastal Adaptation. This framework integrates two levels of analysis. The first one relates with the identification of critical areas affected by coastal flooding and erosion under mean sea-level rise scenarios and the quantification of the extent of flooding, including marine extreme events. The second level assesses the impacts on infrastructures and assets from a socioeconomic perspective due to these hazards.</p><p>In this context, this paper quantifies the effects of sea-level rise and marine extreme events caused by storm surges and waves along the coasts of the Balearic Islands (Western Mediterranean Sea) in terms of coastal flooding and potential erosion. Given the regional scale (~1500 km) of this study, the presented methodology adopts a compromise between accuracy, physical representativity and computational costs. We map the projected flooded coastal areas under two mean sea-level rise climate change scenarios, RCP4.5 and RCP8.5. To do so, we apply a corrected bathtub algorithm. Additionally, we compute the impact of extreme storm surges and waves using two 35-year hindcasts consistently forced by mean sea level pressure and surface winds from ERA-Interim reanalysis. Waves have been further propagated towards the nearshore to compute wave setup with higher accuracy. The 100-year return levels of joint storm surges and waves are used to map the spatial extent of flooding in more than 200 sandy beaches around the Balearic Islands by mid and late 21st century, using the hydrodynamical LISFLOOD-FP model and a high resolution (2 m) Digital Elevation Model.</p>

scholarly journals Developing an early warning system for storm surge inundation in the Philippines

2014 ◽  
Vol 2 (10) ◽  
pp. 6241-6270
Author(s):  
J. Tablazon ◽  
C. V. Caro ◽  
A. M. F. Lagmay ◽  
J. B. L. Briones ◽  
L. Dasallas ◽  
...  
Keyword(s):  
Storm Surge ◽  
Frequency Distribution ◽  
Early Warning ◽  
Early Warning System ◽  
Warning System ◽  
Storm Surges ◽  
The Philippines ◽  
Coastal Areas ◽  
Japan Meteorological Agency ◽  
Series Data

Abstract. A storm surge is the sudden rise of sea water generated by an approaching storm, over and above the astronomical tides. This event imposes a major threat in the Philippine coastal areas, as manifested by Typhoon Haiyan on 8 November 2013 where more than 6000 people lost their lives. It has become evident that the need to develop an early warning system for storm surges is of utmost importance. To provide forecasts of the possible storm surge heights of an approaching typhoon, the Nationwide Operational Assessment of Hazards under the Department of Science and Technology (DOST-Project NOAH) simulated historical tropical cyclones that entered the Philippine Area of Responsibility. Bathymetric data, storm track, central atmospheric pressure, and maximum wind speed were used as parameters for the Japan Meteorological Agency Storm Surge Model. The researchers calculated the frequency distribution of maximum storm surge heights of all typhoons under a specific Public Storm Warning Signal (PSWS) that passed through a particular coastal area. This determines the storm surge height corresponding to a given probability of occurrence. The storm surge heights from the model were added to the maximum astronomical tide data from WXTide software. The team then created maps of probable area inundation and flood levels of storm surges along coastal areas for a specific PSWS using the results of the frequency distribution. These maps were developed from the time series data of the storm tide at 10 min intervals of all observation points in the Philippines. This information will be beneficial in developing early warnings systems, static maps, disaster mitigation and preparedness plans, vulnerability assessments, risk-sensitive land use plans, shoreline defense efforts, and coastal protection measures. Moreover, these will support the local government units' mandate to raise public awareness, disseminate information about storm surge hazards, and implement appropriate counter-measures for a given PSWS.

scholarly journals Integrated Inundation Modeling of Flooded Water in Coastal Cities

2019 ◽  
Vol 9 (7) ◽  
pp. 1313 ◽  
Author(s):  
Eun Shin ◽  
Jaehyun Shin ◽  
Dong Rhee ◽  
Hyung-Jun Kim ◽  
Chang Song
Keyword(s):  
Numerical Models ◽  
Storm Surges ◽  
Coastal Flooding ◽  
Coastal Areas ◽  
Simultaneous Occurrence ◽  
River Flooding ◽  
Coastal Cities ◽  
Flood Simulations ◽  
River Inundation ◽  
Inundation Modeling

Climate change has increased the damage caused by subtropical rainfall and typhoons in coastal areas. Major flooding factors in coastal areas can be classified as storm surges, river inundation, and inland submergence. Because previous studies usually applied a linear sum of individual inundation components to predict comprehensive flood phenomena, this approach does not consider weighted effects associated with the simultaneous occurrence of complex flooding. In this study, a series of comprehensive flood simulations were performed using two numerical models: HDM-2D and FLUval Modeling ENgine (FLUMEN). The results revealed that an integrated flood analysis considering the effects of inundation flooding, river flooding, and coastal flooding required evaluation of the risk of flooding in coastal cities.

Philippine English (Metro Manila acrolect)

2017 ◽  
Vol 48 (3) ◽  
pp. 357-370 ◽  
Author(s):  
Marivic Lesho
Keyword(s):  
Second Language ◽  
Urban Areas ◽  
Large Body ◽  
The Philippines ◽  
Upper Class ◽  
Official Language ◽  
Sound System ◽  
Metro Manila ◽  
English Instruction

English is an official language in the Philippines, along with Filipino, a standardized register originally based on Tagalog (Gonzalez 1998). The Philippines were a Spanish colony for over three centuries, but when the Americans took control in 1898, they immediately implemented English instruction in schools (Gonzalez 2004). It became much more widespread among Filipinos than Spanish ever was, and by the late 1960s, Philippine English was recognized as a distinct, nativized variety (Llamzon 1969). It is widely spoken throughout the country as a second language, alongside Filipino and approximately 180 other languages (Lewis, Simmons & Fennig 2016). It is also spoken in the home by a small number of Filipinos, especially among the upper class in Metro Manila (Gonzalez 1983, 1989) and other urban areas. There is a large body of literature on Philippine English. However, relatively few studies have focused on its sound system. The most detailed phonological descriptions of this variety have been by Tayao (2004, 2008), although there have also been previous sketches (Llamzon 1969, 1997; Gonzalez 1984). There has been very little phonetic research on Philippine English, apart from some work describing the vowel system (Pillai, Manueli & Dumanig 2010, Cruz 2015).

scholarly journals PRELIMINARY ENGINEERING OF A SEAWALL TO MITIGATE TYPHOON-INDUCED WAVE OVERTOPPING ALONG ROXAS BOULEVARD, MANILA

2018 ◽  
pp. 47
Author(s):  
Eric C. Cruz ◽  
Jose Santos ◽  
Laurenz Luigi Cruz
Keyword(s):  
Urban Area ◽  
Transport System ◽  
Storm Surges ◽  
Urban Transport ◽  
Public Works ◽  
Severe Storm ◽  
The Road ◽  
Metro Manila ◽  
Manila Bay ◽  
National Road

Roxas Boulevard is a crucial national road of the urban transport system of Metro Manila. The road is protected from the sea hazards of Manila Bay by Roxas Boulevard Seawall. This gravity-type seawall also protects the important recreational promenade and high-value properties behind the wall. The seawall was overtopped several times by recent strong typhoons. In 2011, it collapsed after storm surges and waves generated by Typhoon Nesat overtopped it and caused substantial flooding of a vast urban area of Manila city just behind the seawall. It was rebuilt quickly after that but only to be overtopped again by severe storm tides and high waves from subsequent strong typhoons. A study was commissioned by the national public works agency DPWH to understand the causative processes and provide basis for suitable mitigating solutions against overtopping of the seawall. This study discusses the typhoon-induced hydrodynamics in Manila Bay and the preliminary engineering undertaken to design one of the engineering interventions that were recommended to mitigate seawall overtopping.

scholarly journals ASSESSING THE HYDROLOGIC EFFECTS OF URBANIZATION THROUGH NUMERICAL MODELING USING SWAT: A CASE STUDY OF LAGUNA DE BAY BASIN

2021 ◽  
Vol XLVI-4/W6-2021 ◽  
pp. 193-199
Author(s):  
J. M. Jamilla ◽  
J. Serrano ◽  
B. C. Hernandez ◽  
E. Herrera
Keyword(s):  
Land Cover ◽  
Urban Areas ◽  
Flood Control ◽  
The Philippines ◽  
Wet Season ◽  
Metro Manila ◽  
Laguna De Bay ◽  
The Impact

Abstract. Laguna de Bay, having a surface area of about 900 km2 is the largest freshwater lake in the Philippines, and is the most important water body in Metro Manila with its variety of uses ranging from aquaculture, irrigation, water supply and flood control. Due to its available resources and strategic location, over extraction, land conversion, and urbanization, have resulted in massive changes in the lake's watershed. The objective of this study is to simulate the impact of land cover change, particularly urbanization, on the hydrology of Laguna de Bay watershed. By hypothetically converting brushland to urban areas and using ArcSWAT to simulate the effects of urbanization, discharges and water balances were assessed. The long-term hydrologic simulations showed an annual increase of 20.6 m3/s (68%) in surface runoff and a 12.8 m3/s (26%) decrease in groundwater recharge for the entire watershed as urban areas increase. The mean seasonal flows were 75. m3/s during the dry season and 149.4 m3/s during the wet season for the original land cover, and 70.2 m3/s and 154.1 m3/s for the urbanized land cover, during the dry and wet seasons, respectively. Water percolating into the aquifers beneath the ground were also lessened by 13.6 m3/s (23%). The calibration of Marikina subbasin resulted to a satisfactory percent bias (PBIAS), Nash-Sutcliffe (NSE), and the ratio of the root-mean-square error to the standard deviation of measured data (RSR). Other subbasins resulted in a relatively lower performance rating due to limited available monitoring stations within the basin.

WAVE CLIMATE OF THE BLACK SEA’S COASTAL WATERS DURING THE LAST THREE DECADES

2017 ◽  
Author(s):  
Fedor Gippius ◽  
Fedor Gippius ◽  
Stanislav Myslenkov ◽  
Stanislav Myslenkov ◽  
Elena Stoliarova ◽  
...  
Keyword(s):  
Wind Speed ◽  
Cell Size ◽  
Coastal Waters ◽  
Wind Wave ◽  
Spatial Scales ◽  
Wave Model ◽  
Wave Climate ◽  
Computational Grid ◽  
Coastal Areas ◽  
Wave Parameters

This study is focused on the alterations and typical features of the wind wave climate of the Black Sea’s coastal waters since 1979 till nowadays. Wind wave parameters were calculated by means of the 3rd-generation numerical spectral wind wave model SWAN, which is widely used on various spatial scales – both coastal waters and open seas. Data on wind speed and direction from the NCEP CFSR reanalysis were used as forcing. The computations were performed on an unstructured computational grid with cell size depending on the distance from the shoreline. Modeling results were applied to evaluate the main characteristics of the wind wave in various coastal areas of the sea.

scholarly journals Country-level determinants of the severity of the first global wave of the COVID-19 pandemic: an ecological study

BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e042034
Author(s):  
Tiberiu A Pana ◽  
Sohinee Bhattacharya ◽  
David T Gamble ◽  
Zahra Pasdar ◽  
Weronika A Szlachetka ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Vaccination Coverage ◽  
Urban Areas ◽  
Ecological Study ◽  
Environmental Parameters ◽  
The Philippines ◽  
International Travel ◽  
Bcg Vaccination ◽  
Country Level ◽  
The Mean

ObjectiveWe aimed to identify the country-level determinants of the severity of the first wave of the COVID-19 pandemic.DesignEcological study of publicly available data. Countries reporting >25 COVID-19 related deaths until 8 June 2020 were included. The outcome was log mean mortality rate from COVID-19, an estimate of the country-level daily increase in reported deaths during the ascending phase of the epidemic curve. Potential determinants assessed were most recently published demographic parameters (population and population density, percentage population living in urban areas, population >65 years, average body mass index and smoking prevalence); economic parameters (gross domestic product per capita); environmental parameters (pollution levels and mean temperature (January–May); comorbidities (prevalence of diabetes, hypertension and cancer); health system parameters (WHO Health Index and hospital beds per 10 000 population); international arrivals; the stringency index, as a measure of country-level response to COVID-19; BCG vaccination coverage; UV radiation exposure; and testing capacity. Multivariable linear regression was used to analyse the data.Primary outcomeCountry-level mean mortality rate: the mean slope of the COVID-19 mortality curve during its ascending phase.ParticipantsThirty-seven countries were included: Algeria, Argentina, Austria, Belgium, Brazil, Canada, Chile, Colombia, the Dominican Republic, Ecuador, Egypt, Finland, France, Germany, Hungary, India, Indonesia, Ireland, Italy, Japan, Mexico, the Netherlands, Peru, the Philippines, Poland, Portugal, Romania, the Russian Federation, Saudi Arabia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the UK and the USA.ResultsOf all country-level determinants included in the multivariable model, total number of international arrivals (beta 0.033 (95% CI 0.012 to 0.054)) and BCG vaccination coverage (−0.018 (95% CI −0.034 to –0.002)), were significantly associated with the natural logarithm of the mean death rate.ConclusionsInternational travel was directly associated with the mortality slope and thus potentially the spread of COVID-19. Very early restrictions on international travel should be considered to control COVID-19 outbreaks and prevent related deaths.

scholarly journals The Level of Public Acceptance to the Development of a Coastal Flooding Early Warning System in Jakarta

2021 ◽  
Vol 13 (2) ◽  
pp. 566
Author(s):  
Nelly Florida Riama ◽  
Riri Fitri Sari ◽  
Henita Rahmayanti ◽  
Widada Sulistya ◽  
Mohamad Husein Nurrahmat
Keyword(s):  
Path Analysis ◽  
Early Warning ◽  
Early Warning System ◽  
Warning System ◽  
Coastal Flooding ◽  
Coastal Areas ◽  
Public Acceptance ◽  
Community Attitudes ◽  
Early Warning Model ◽  
Warning Model

Coastal flooding is a natural disaster that often occurs in coastal areas. Jakarta is an example of a location that is highly vulnerable to coastal flooding. Coastal flooding can result in economic and human life losses. Thus, there is a need for a coastal flooding early warning system in vulnerable locations to reduce the threat to the community and strengthen its resilience to coastal flooding disasters. This study aimed to measure the level of public acceptance toward the development of a coastal flooding early warning system of people who live in a coastal region in Jakarta. This knowledge is essential to ensure that the early warning system can be implemented successfully. A survey was conducted by distributing questionnaires to people in the coastal areas of Jakarta. The questionnaire results were analyzed using cross-tabulation and path analysis based on the variables of knowledge, perceptions, and community attitudes towards the development of a coastal flooding early warning system. The survey result shows that the level of public acceptance is excellent, as proven by the average score of the respondents’ attitude by 4.15 in agreeing with the establishment of an early warning system to manage coastal flooding. Thus, path analysis shows that knowledge and perception have a weak relationship with community attitudes when responding to the coastal flooding early warning model. The results show that only 23% of the community’s responses toward the coastal flooding early warning model can be explained by the community’s knowledge and perceptions. This research is expected to be useful in implementing a coastal flooding early warning system by considering the level of public acceptance.

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