MANILA, Philippines – The deluge that devastated Metro Manila on September 26 was a poignant scene. Though vivid in the minds of residents, the memory will eventually fade, and in time remembered only by a few.

When awareness of the flood disaster fades, residents become vulnerable once more, exposed to ruthless Nature.

A web-based interactive map showing flood levels in Metro Manila has been created to serve as a permanent record to help keep residents of today and the future reminded of the catastrophe.

Called the typhoon Ondoy Maximum Flood Height Map [It was actually a tropical storm.], residents can add their recollection of the inundation of the metropolis and adjacent areas.

One can go to http://maps.google.com and type typhoon Ondoy. Then select Typhoon Ondoy Maximum Flood Height (See How to add to the database).

One can also go to http://maps.google.com/maps/ms?msa=0&msid=
115956470311312588880.000474a2
30d17e01a3021&ie=UT F8&z=13

Someone using Google maps can input his or her account of the maximum flood heights in the place where inundation of streets and residences occurred.

UP team

The day after the Ondoy disaster, I thought of creating the interactive map. I asked the team from the UP Volcano Tectonics (VTEC) laboratory of the National Institute of Geological Sciences (NIGS) – Grace Bato, JB Libao, Raymond Rodolfo, Lorraine Pastoriz and Hillel Cabria – to help create and put up the site.

On September 28, the interactive site was online. Manila Observatory helped by linking the site to its web page, providing suggestions and co-managing the site.

The idea of the interactive map was prompted by the need to determine actual height measurements of flooding in every part of the metropolis.

Disaster mitigation

Cyberspace technology had to be used to bridge the desire of the community to help with disaster mitigation efforts. It is well known that hazard preparedness is at its best when the community participates.

(A review of the Google map page shows several sites that have a similar format. These are the Ondoy Situation Map for Metro Manila (created Sept. 26), Ondoy Relief Goods Donation Centers (created September 28), and NDCC asset deployment for the first 48 hours of Ondoy (created October 3).

Wildfires in North America

In North America, there are several interactive maps showing wildfires using Google maps and are precedents to this type of disaster mitigation effort.

When completed, the interactive map can be used to generate a hazard map showing the different levels of inundation in Metro Manila.

The geographic data can also be used for validating numerical simulations of floods, important for hazard mapping and urban development planning.

Hydrological hazard maps

Although there are existing hydrological hazard maps for most parts of Metro Manila, the unprecedented flooding that Metro residents experienced was not predicted by these charts. Otherwise, the disaster caused by Ondoy could have been avoided or minimized.

Slowly, the picture of Ondoy flood levels is emerging. However, there is much to be desired with regard to the depiction of the actual picture of the deluge. There is a need to get as many entries as possible distributed in every street of Metro Manila and its neighboring areas.

More entries in the interactive map mean better accuracy of the survey. Invalid input data can be checked by comparing predisaster images with satellite images taken after the flood. (See maps.)

Erroneous inputs can also be weeded out using proper statistical analysis of a large dataset.

Page views

As of October 6, there were about 600 entries made in the interactive flood map by more than 300 citizens/netizens. There are already more than 51,000 views of the interactive Google map and the number of entries is growing fast. The individual profiles of contributors are unknown and will remain so for their best interest.

The flood-mapping project took off without many problems. However, the project team is trying to reach more residents and encourage them to contribute to the mapping effort.

Lola Techie

UP NIGS and the Manila Observatory, Ateneo de Manila University provide an alternative to those who are not as Internet savvy as Lola Techie. You can e-mail ondoy@nigs.upd.edu.
ph or klima@observatory.ph and send the details of your desired input.

The interactive map needs to be linked to a blogspot or permanent webpage. There, we can add more instructions. As of the moment, there is a maximum-character limit to the instructions we can put beside the interactive Google map.

Cell phones

Also, some people don’t want to create a Google account. We now provide another option for inputs in which they just e-mail us the details of their contributions and we will input the placemarks ourselves.

Since cell phones are handy, major cell-phone companies will soon be requested to send a text message to all their subscribers, urging them to participate in the flood-mapping effort in Metro Manila. Alternatively, people can call 9242904 (VTEC laboratory, UP NIGS) or 4265921 (Klima, Manila Observatory).

The response of local government officials has yet to be determined. Those involved in the mapping project, however, look forward to getting their support in collecting data from their respective districts.

Preparing for future floods in Metro Manila takes community effort. We can tap the bayanihan spirit of Filipinos for mitigating disasters. Let us act now and plan ahead.

(Dr. Alfredo Mahar Lagmay is an associate professor at the National Institute of Geological Sciences, University of the Philippines. He holds a Ph.D. in geology from the University of Cambridge and was a visiting scientist at the Geophysics Department of Stanford University.

He lectures on Philippine disasters in the Science, Technology and Society Program of the College of Science, UP, by virtue of having hands-on experience in search-and-rescue-and-forensic analyses of major Philippine disasters in the last five years. These include the Mindoro flood, Guinsaugon landslide, Mayon lahar, Iloilo flood and Cagayan de Oro disasters. He has worked with scientists from the Manila Observatory in these projects.

A recipient of the 2008 Outstanding Research Award for advanced science and technology in the Philippines for his work on innovative application of space technology on Philippine volcanoes, he continues his service to the Filipino people by conducting volunteer work in areas stricken by disaster.)

How to add to the database

1 One has to have a Gmail account and sign in.

2 Press the edit button and add a placemark. For accuracy, zoom in until one sees the houses clearly before plotting the location.

3 Input the flood heights as the title and follow the legend below.

4 To edit or change the icon, click the image/icon at the right side of the title bar.