Flood Hazard Map Legend is based on Manny Pacquiao's height of 1.69 meters or 5'6 1/2 ft.
The Philippines being a locus of typhoons, tsunamis, earthquakes and volcanic eruptions, is a hotbed of disasters. Natural hazards inflict loss of lives and costly damage to property. Last year, the devastating impacts of Pedring, Quiel and Sendong resulted in a high number of fatalities with economic losses amounting to billions of pesos. Extreme weather is the common factor in these latest catastrophes. Situated in the humid tropics, the Philippines will inevitably suffer from climate-related calamities similar to those experienced recently. With continued development in the lowlands, and growing populations, it is expected that damage to infrastructure and human losses would persist and even rise unless appropriate measures are immediately implemented by government.
In response to President Aquino's instructions to put in place a responsive program for disaster prevention and mitigation, specifically, for the Philippines' warning agencies to be able to provide a 6 hour lead-time warning to vulnerable communities against impending floods and to use advanced technology to enhance current geo-hazard vulnerability maps, the Nationwide Operational Assessment of Hazards (NOAH) was launched by the Department of Science and Technology.
NOAH's mission is to undertake disaster science research and development, advance the use of cutting edge technologies and recommend innovative information services in government's disaster prevention and mitigation efforts. Though the use of science and technology and in partnership with the academe and other stakeholders, the DOST through Program NOAH is taking a multi-disciplinary approach in developing systems, tools, and other technologies that could be operationalized by government to help prevent and mitigate disasters.
NOAH's immediate task is to integrate current disaster science research and development projects and initiate new efforts within the DOST to achieve this objective. Presently there are nine(9) component projects under the NOAH program, namely:
The current NOAH Program team is composed of the scientist-leaders of these projects. The country's warning agencies: PAG-ASA and PHIVOLCS are also represented.
Within two years, NOAH shall provide high-resolution flood hazard maps and install 600 automated rain gauges and 400 water level measuring stations for 18 major river basins of the Philippines, namely:
The other river basins of the Philippines will follow soon after the work on the 18 major river basins is completed.
The hazard maps are produced with computer simulations that reflect flood-prone areas discernible at a local scale or community level. Such maps are necessary for localized emergency response, identification of evacuation and access routes, road closures during disaster events, siting of key rescue facilities and comprehensive land use planning. The initial output of Project NOAH is focused on the Marikina Watershed. As of July 6, 2012, streaming data from the automated rain gauges and water level sensors, flood hazard maps overlain on Google Maps, graphical satellite radar and Doppler data forecasts, and translated rain intensity and volume measurements in terms of warning and evacuation level alarms, hours or days ahead of the flood event, are accessible online. The output on the Marikina Watershed will serve as the prototype of the efforts done by NOAH and will be replicated for the entire Philippines. Information generated shall also be transmitted using other media and communication channels. Through the use of advanced science and technology, NOAH aims to improve disaster management capacity of local governments and assure homeland security by reducing casualties and property loss from extreme hazard events.
The Nationwide Operational Assessment of Hazards (NOAH) program team will collaborate with government agencies to promote and integrate advanced science and technology to enhance disaster management and prevention capacity of the Philippine government. These include: the deployment of instruments and state-of-the-art methods to construct high resolution hazard maps that are relevant to the community and local government units; delivery of readily accessible, timely and accurate hazards information through various media and communication platforms; disaster research and development; integration of disaster efforts by the national government, academe and civil society organizations; and application of a bottom-up approach by communities to resilience against disasters.
To assure homeland security by reducing casualties and property loss from extreme hazard events and build disaster resilient communities in the Philippines by way of establishing research and development platforms and the promotion of frontier science and technology in disaster efforts.
To become a world leader in programs that leverage on advanced science and technology to mitigate the impacts of natural hazards.
Initial Web Development by Icannhas Inc.
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The Project NOAH website is one of the information dissemination platforms designed by the government to mitigate and prevent disasters. With the use of the Internet, critical, reliable, authoritative, understandable, and timely information is conveyed to communities and local government units. The website contains detailed weather and disaster information, which, when used properly, can avoid the loss of lives and damage to properties due to the impacts of natural hazards. A step-by-step approach on the use of the Project NOAH website is discussed in the manual. It also contains instructions on how to interpret the features correctly in the context of impending local disasters.
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The Project NOAH website can be accessed through any Internet browser by typing the URL http://www.noah.dost.gov.ph. It can also be searched using Google by typing Project NOAH and clicking the first entry on the list of results.
Once the Project NOAH website opens, a Google map of the Philippines will show up on the home page. (Figure 1).
Figure 1. The NOAH website showing a Google map of the Philippines once it’s opened.
The lower right corner of the page shows the Twitter messages of PAGASA, which is the primary source of information related to weather and floods. Information posted on the NOAH website is supplementary to the official advisory given by PAGASA.
Located on the top left part is the zoom tool of Google. On the opposite side are the STREET, TERRAIN, and HYBRID buttons, which are used for selecting the type of maps that the viewer likes. The TERRAIN view is highly recommended for a faster Internet experience. Beside the map type button is the transparency slide bar that sets the opacity of overlays.
Users can scroll real-time rainfall measurements of automated rain gauges on the lower part of the website.
Figure 2. Tool bar on the DOST Project NOAH website.
The blue tabs on the top right corner (Figure 2) allow the viewer to activate or deactivate the TOOLS tabs and LEGEND icons, as well as to navigate other Project NOAH documents, including the BLOG, ABOUT, HELP, and REPORT A FLOOD pages.
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When the TOOLS tab is activated, this feature above the map of the Philippines will appear. (Figure 3)
Figure 3. The toolbar menu.
The toolbar menu is the main gateway to access the different features of the Project NOAH website. This menu enables the viewer to select various displays that show weather information and flood maps for the Philippines.
The SEARCH tab is used when there is a need to display community-scale hazard maps in any part of the country. This feature allows the viewer to zoom into any location in the Philippines. Upon typing the address and activating the search engine, the user is automatically directed to the place of interest and given access to Provincial, Municipal and Barangay scale maps.
To get a quick view of weather-related data in the Philippines, users are advised to check the OVERVIEW tab (Figure 4) first. There are many choices: The Multi-functional Transport Satellite Image (MTSAT) is an animated image that show cloud formation above the country and in the surrounding seas. Rainfall, temperature, pressure, and humidity contour maps show the weather condition anywhere in the Philippines at aglance. The 3, 6, 12 and 24-hour rainfall contours show areas in the Philippines that have been experiencing heavy downpour. Lastly, the percent chance of rain contour allows viewing of areas that are most likely to experience rainfall, every hour or up to four hours in advance.
Figure 4. The overview tab functions are used to display the general weather condition in the Philippines.
The MTSAT and processed images show the temperature of the cloud formations (Figure 5). During instances when there are cyclones within the Philippine Area of Responsibility (PAR), clouds are often seen swirling around the eye of the typhoon or storm.
Figure 5. MTSAT image showing typhoon Lawin (international codename Jelawat).
Figure 6. Processed satellite image. White clouds indicate areas where rain may fall.
The processed satellite image shows white clouds that can bring forth rain. It is an animation of the five latest sequential images downloaded by the satellite ground station of PAGASA. At the lower left corner of the animated file is the timestamp in both the MTSAT and processed imageries. The timestamp may have a one-hour delay, which is acceptable because it requires time to download data from the satellite orbiting at 36,000 km above the earth’s surface and process them into an animated file.
After viewing the satellite imageries, the user can activate the rainfall contour button (Figure 7) in the overview tab options. The one-hour rainfall contour shows places in the Philippines that have experienced rain as measured by the automated weather stations (AWS) and automated rain gauges (ARG) deployed all over the Philippines. A scale bar can be used on the left side of the page to learn about the type of rainfall according to the classification of PAGASA. To explain the various rain types, here’s a useful analogy using the car windshield wiper (Table 1).
Table 1. Wiper analogy for various types of rain.
Figure 7. Rainfall contour of rainfall accumulation in Central and Southeast Luzon.
The next tab to check is the 3-hour rainfall contour button (Figure 8).
Figure 8. The 3-hour rainfall contour button.
Floods are generated by intense and torrential rainfall delivered in a watershed over a prolonged period. When red and yellow colors appear in the Philippine map with a 3-hour rainfall contour overlay, it means that a region of the country is experiencing heavy downpour and is prone to generating floods that can inundate low-lying areas. Floods during heavy and prolonged downpour are produced depending on the size of the watershed, intensity of rain, volume of rain, type of land cover, and other factors.
In short, predicting whether floods will happen or not in an already drenched area, is not as easy as one can imagine. Nonetheless, rainfall contours that show a large accumulation of rain can give an indication of potential floods and be used to alert people about a potential danger. To get a quick view of areas in the Philippines affected by intense and torrential rainfall, the user must check this feature and the 6-hour, 12-hour, and 24-hour rainfall contour maps in the OVERVIEW tab. For comparison, look at the previous flood disasters and the amount of rain poured within the watershed listed on Table 2.
Table 2. List of recent flood disasters in the Philippines and the corresponding rain intensity and volume delivered in respective watersheds.
Table 3. Color-coded warning system of PAGASA for urban flooding in Metro Manila. Source: PAGASA
Other OVERVIEW options on the Project NOAH website are TEMPERATURE, PRESSURE, and HUMIDITY contours (Figure 9), which are used to check additional weather parameters. For example, the pressure contour map can be used along with the typhoon track of PAGASA to validate if the storm or typhoon is going to pass through the region where atmospheric pressure is lowest. There is normally a drop in the atmospheric pressure before a storm arrives. As for all overlays on the NOAH website, it is important to check the timestamp to get a more accurate reading. For the contour maps, the timestamp is located on the top left of the Philippine map.
Figure 9. Contour maps showing temperature, pressure and humidity.
The last option in the OVERVIEW tab is the RAINFALL PROBABILITY contour. Probabilities of rainfall for every city in the Philippines are available, but instead of looking at the hourly chance of rain per city, these have been reformatted into a map of rain probability. This way, users can see the chance of rainfall in every region of the country at a glance. This is useful when they just want to quickly check a specific area that’s likely to experience rain in the next four hours. The probability contour map is animated every hour up to four hours from the time it was last updated.
Figure 10. Chance of rain contour. Scale bar to the left of the Philippine map shows the percentage chance of rain with red and maroon colors depicting 80-100% chance of rain in the next hour from the last update.
WEATHER OUTLOOK is the next tab in the TOOLS menu. By selecting the RAIN FORECAST feature in the options, a map with icons of percentage chance of rain will appear on the Philippine map for every key city in the Philippines.
Table 4. Probaility of rain icons and equivalent percent chance of rain.
When the icon is selected, a table appears showing the probability of rainfall every hour up to four hours ahead of the current time (Figure 11). It is important to check when the analysis was last generated to ensure accuracy. The reliability of the forecast, which is based on the validation of ClimateX, is about 95 percent when all data sources (Satellite, Doppler, Rain Gauges) are up-to-date.
Figure 11. Percent chance of rain for every key city in the Philippines.
Figure 12. Weather Outlook.
Weather Manila’s 3-hourly weather forecast shows the relevant weather information averaged over 3 hours starting from 12 midnight Philippine standard time.
TemperatureDisplays the 3 hour averaged temperature for the specified time span.
Real FeelSometimes referred to as ‘Real Feel’, this is what we feel when high temperature is aggravated by high humidity.
Relative HumidityDisplays 3 hour averaged relative humidity. Gives a measure of water content (saturation) of air
RainfallDisplays 3 hour averaged precipitation or rainfall. 0~1mm/hr generally is very light to light rain. 2~5mm/hr is moderate rain and more than 5 mm/hr is heavy rain.
Whenever there is a tropical cyclone in the Philippine Area of Responsibility (PAR), another option appears in the WEATHER OUTLOOK tab. This is the PAGASA typhoon cyclone forecast track. By selecting this feature along with the MTSAT image in the OVERVIEW tab, a view of the actual position of the cyclone and the forecast track can be seen (Figure 13).
Figure 13. PAGASA forecast track of typhoon Nina (international codename Prapiroon) overlain on the MTSAT image of the Philippines, taken early morning of October 12, 2012.
The outline of the Philippine Area of Responsibility also appears when the forecast track feature is activated. This feature allows the viewer to determine the position of the satellite and the forecast relative to PAR.
The DOPPLER tab allows the selection of animated images from the Doppler radar stations of PAGASA. There are currently six Doppler radar stations that monitor rain clouds in the country. Four of these stations stream data into the Project NOAH website. These are the Subic, Tagaytay, Cebu, and Hinatuan Doppler stations. As soon as communication lines are fixed to stream the data from the Baguio and Virac Doppler stations into DOST-ASTI servers, the raw radar shall be processed and made available. By 2014, there will be a total of 13 operational Doppler radar stations to monitor weather conditions in the country. Every raincloud can be seen and measured in terms of the intensity and volume of precipitable water (Figure 14).
Figure 14. Doppler image from Subic station during “Habagat”. Screenshot taken at 7 am on August 7, 2012. Pink rain clouds indicate high intensity rain.
When a station is selected, a circle appears with its center corresponding to the location of the receiving Doppler radar. The acquisition coverage of most of the Doppler radar instruments in the Philippines is up to about 400 km and is shown as a black outline. If there are rain clouds within the coverage area, they will appear as colored clouds. A reference scale bar for the cloud color is provided on the right side of the Philippine map, which shows rainbow colors with their corresponding rainfall intensity values in millimeters per hour. Light blue means light rain while the red and pink clouds range from intense to torrential rains.
The southwest monsoon rains experienced by people living in Greater Metro Manila from August 6 to 8, 2012 were detected by the Doppler radar stations in Subic and Tagaytay. There were a lot of pink-colored clouds that moved over Laguna, National Capital Region, Bulacan, Pampanga and Zambales, which were felt by Metro Manila residents when heavy rain continued to fall. The rainfall also made the Marikina River rise twice, prompting forced evacuation in low-lying areas in Montalban, San Mateo, and Marikina. Malabon and Navotas, including many parts of Bulacan, were also inundated.
The WEATHER STATIONS tab allows viewing of data for each automated sensor deployed in strategic parts of the country. At the time of writing, there are already more than 700 weather stations that provide Project NOAH with data on rainfall and river water level every 10 to 15 minutes. By the end of 2013, more than 1000 automated rain gauges and water level sensors are expected to be set up.
There are three types of weather stations: the Automated Weather Station (AWS), the Automated Water Level Sensor (AWLS), and the Automated Rain Gauge (ARG). Each type of sensor is included in the WEATHER STATION tab. Selecting all of these options will show the distribution of the entire collection of sensors located all over the Philippines. (Figure 15)
Figure 15. Automated weather stations deployed all over the Philippines.
Three types of colored pins will appear on the Philippine map. The blue pins represent automated weather stations, red pins are for automated water level sensors, and the green pins are for automated rain gauges. Depending on the zoom level, numbers may appear on the balloon head of the pins. These represent the number of pins in a cluster that separate when the Philippine map is zoomed in.
When the blue pin is clicked twice, a graph appears showing the data of the rainfall, temperature, pressure, and humidity in the last 24 hours. The rainfall data (Figure 16a) are color-coded to represent the types of rainfall based on the classification of PAGASA. Temperature data (Figure 16b) are shown in a degree-centigrade versus time graph. Atmospheric pressure data (Figure 16c) are shown in a pressure versus time graph. The unit of pressure is measured in hectopascals (hPA), where 1 hectoPascal is equal to 100 Pascals. Lastly, humidity is shown in terms of percentage humidity versus time graph (Figure 16d).
Figure 16. a) Top left showing the rain gauge graph b) top right showing the temperature graphs c) bottom left showing the pressure graph d) bottom right showing the humidity graph
Inspection of ARG data is possible by clicking on any of the green pins twice. Once selected, a graph similar to the AWS rainfall data appears on screen (Figure 17). Peaks in the graph signify rainfall of a particular type of rainfall intensity (i.e. torrential, intense, heavy, moderate, or light) when matched with the colored background. By moving the cursor along the X-axis, the user will see the amount of rainfall collected every 10 or 15 minutes over the last 24 hours.
Figure 17. Rainfall graph the last 24 hours.
The stream gauge option of the SENSORS tab shows the location of all the river water level gauges installed by PAGASA and DOST-ASTI in the 18 priority river basins of Project NOAH. To access data from each of the stream gauges, select the red pin and a graph will appear showing the data collected in the last 24 hours. A color-coded background will provide the matching assessment level of potential fluvial flooding (Figure 18).
Three warning levels are designated in the graph: the alert, alarm, and critical level. They are classified based on the percentage height of water flow relative to bank full (Figure 19). These stages of surface height of water correspond to 30 percent, 60 percent and 90 percent of bankfull, respectively.
Figure 18. Graph of water level of the Marikina River (Sto. Nino station). Water levels during “Habagat” reached 20.5 meters twice in the span of 3 days.
However, the local government may adopt their own scheme of warning levels. For example, the Marikina City Council (http://syncsysph.com/councilmarikinagovph/data/riverlevel.html) uses its own system in warning its residents. When the water level of the Marikina River reaches 15 meters, residents living in low-lying areas beside the river are warned of impending danger. At 16 meters, residents are asked to prepare to evacuate. When the level of the Marikina River reaches 17 meters, people are asked to evacuate. Those that do not follow these instructions are forced to leave when the water level reaches 18 meters. All warning levels of the Marikina City Council are based on measurements and reports from the Sto. Nino station.
Figure 19. Schematic cross-section of a river showing bankfull and percentage levels relative to bankfull level.
Giving warnings about suspension of classes is essential in disaster prevention. However, it is necessary that they are relayed to residents and clearly understood by everyone in the community long before crises happen. The warning levels are unique to each river and its location along the river. They are determined based on a thorough assessment of carrying capacity and the response of the fluvial system to rainfall events.
Selecting the FLOOD MAP tab will display flood maps that represent past scenarios of flood events and near real-time simulations of river conditions in map view. In general, the scenarios from past flood events in rivers for 18 major basins (Table 5) are used to help people prepare for flood disasters several years in advance. These maps can be used to identify flood hazard areas, distinguish possible blocked roads, determine emergency access routes, and strategize placement of rubber boats and key emergency facilities, among others. Most importantly, they should be used for comprehensive land development plans. Avoiding land development in known compromised areas lessens the impact of natural hazards because fewer people will be in harm’s way. Forecast simulations of floods based on near real-time data provide important basis for action during a crisis situation.
Table 5. A list of the 18 major river basins prioritized by Project NOAH, which includes the Infanta and Lucena watersheds.
Past scenarios of inundation shown on the Project NOAH website are simulated flood events that arise from different intensities and duration of rainfall. Records of such rainfall in different areas of the country are documented by PAGASA and go back as far as the 1950s. To group the different types of rainfall events, they have been classified according to their statistical return period of 5, 10, 25, 50 and 100 years. The probability of a 5-year rain return period is 1 in every 5 years while the probability of a 100-year rain return period is 1 in every 100 years. In simple terms, the strength of rainfall for a 100-year rain return is much stronger but less frequent than it is for a 5-year rain return. Since statistical rain return periods refer to probability (“chance” in gambling talk), the chance of having a100-year rain return period rainfall event in consecutive years or within the same year is also possible. Once it happens, the probability clock is reset. For each of these 1 to 100-year rain return events, corresponding flood scenarios are generated using computer simulations of water runoff on land.
On the other hand, the flood scenarios determined through near real-time rainfall measurements predict the flood distribution and depth of inundation of areas by the river. Since these real-time scenarios are simulated using fast computers, it warns people ahead of time about what kind of flood may happen. These flood scenarios help communities and local government units to make early preparations and come up with logical decisions for an impending flood disaster.
For example, the land area of San Mateo and Marikina with overlays of various flood scenarios is shown below. High, medium, and low hazard levels are indicated in yellow, orange, and red, respectively. Selecting the LEGEND tab in the top right buttons will display the equivalent height of the different colors relative to a Filipino, 5 feet and 6 inches in height or as tall as the boxing legend Manny Pacquiao.
Figure 20. Flood hazard map using the 5-year rainfall return period data of PAGASA.
Figure 21. Flood hazard map using the 25-year rainfall return period data of PAGASA.
Figure 22. Flood hazard map using the 50-year rainfall return period data of PAGASA.
Figure 23. Flood hazard map using the 100-year rainfall return period data of PAGASA.
Figure 24. Flood hazard map using the recorded rainfall of Ondoy on 26 September 2009.
The viewer can look for an address using the SEARCH feature of the site. Zoom toolbars are located in the top left corner of the map page. The mouse scroll button can also be used to zoom in and out the map.
Figure 25. Simulation of the Ondoy flood in Talayan, Quezon City with overlay anecdotal accounts of floods using crowdsourcing techniques. Red dots mean overhead flood, while green dots indicate the lack of flood.
The flood scenarios generated from near real-time rainfall data use computers that run simulations every ten minutes, 24 hours a day and 7 days a week. The output is automatically integrated as plan- and cross-section views (Figure 26a and Figure 26b) into the Project NOAH website.
Figure 26. Simulation of flood along the Marikina River during Habagat from August 6 to 9 and the rainfall events on July 3. Source: DREAM-Project DOST panel technical presentation.
Figure 27. Near-real time simulation of the Pasig river as seen on the website.
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The LEGEND tab serves as a reference for water level in the flood hazard map. The Project NOAH team has chosen to classify the depth of flood in three types for easier understanding. The LOW flood hazard means that the flood is knee-high at 0.5 meters. The MEDIUM flood hazard means that the water level is from the knee up to the ears at 1.5 meters. Lastly, the HIGH flood hazard, which is the most dangerous, means that the inundation level reaches way above the forehead.
Another factor that influences flood hazards is the velocity of flowing water. Even if the water is only waist-high, if the velocity of moving flood water is about 2 m/s2, then the hazard is considerable.
Figure 28. Flood Hazard Map Legend is based on Manny Pacquiao's height of 1.69 meters or 5'6 1/2 ft.
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The blog features news items about Project NOAH, its project components as well as interviews of program leader, Dr. Alfedo Mahar Lagmay, and other project leaders . It also features updates on latest developments, outputs, and initiatives of the project; and serves as repository for publications, articles, and other information materials that can be used as references by interested researchers or institutions.
Figure 29. The Project NOAH Blog Site.
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The About page provides background information on Project NOAH, its priority areas, and the mission and vision of the project.
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This tab will redirect the website user to nababaha.com, Project NOAH’s repository for flood reports utilizing the crowd sourcing technique. Here, one can report about a flood event in a particular area and their corresponding level.
The above model is a 90-hr storm surge forecast generated using Japan Meteorological Agency (JMA) numerical model. The model covers 12:00mn of 8 November 2013 to 06:00pm of 11 November 2013 (UTC).
The legend indicates storm surge height in centimeters. A storm surge is a rise in the water level over and above the predicted astronomical tide due to the presence of the storm.
For more details on specific coastal storm tide level details, please visit Project NOAH Website and look into the Weather Stations option, and click the YolandaPh Storm Tide Level.
Clicking the pin ( ) will display the forecast storm tide levels for November 9 to 12 on that area.