PhiL-LiDAR 1: Hazard Mapping of the Philippines using LiDAR

  • Written by  Regina Mae C. Ongkiko
  • Published in Features

Resilience. It is the ability to recover quickly from difficulties or challenges. It’s another moniker for toughness, and Filipinos are known all over the world for that trait.

The word is often used during typhoon season in the country. Even after experiencing some of the worst natural disasters, Filipinos always find reasons to smile. Kids wading in waist-deep floodwater is not an uncommon sight. In the absence of electricity, we find ingenious and creative ways to entertain ourselves and have fun with makeshift basketball courts, outdoor games, and scavenger hunts.

While the tenacity of the Filipino people is admirable, how do we move beyond this? How do we focus on solutions instead of just ‘laughing it off’ and accepting that these disasters happen every year?

With climate change looming over us, typhoons and floods are expected to increase. Even though Filipinos remain resilient and strong enough to overcome tragedies, the need to be better prepared for these natural disasters is becoming even more evident.

The project that moved a country

With the vision of ‘resilient Filipino communities that can rise above any environment-related disaster,’ the DREAM Program used the LiDAR technology to come up with detailed and up-to-date topographic maps of flood-prone areas in the country.

Former Department of Science and Technology Secretary Mario Montejo previously said that “the fine-resolution maps produced by LiDAR technology can serve as the basis for early warning systems for communities that are prone to flood hazards and other challenges.” There is hope that government agencies and other sectors can work together to use these maps for disaster risk reduction.

DREAM covered 18 major river basins which make up a third of the total area of the Philippines’ river systems. Even so, it became known as one of the most extensive three dimensional mappings in Southeast Asia in 2012.

When DREAM transitioned to the Phil-LiDAR Project in 2014, it expanded its original goal of mapping the 18 major basins to 300. Phil-LiDAR 1: Hazard Mapping of the Philippines was tasked to cover the remaining two-thirds of the Philippines’ river systems.

There was no time to slow down as the importance of this program was emphasized as the onslaught of typhoons came and went. The University of the Philippines Los Baños joined thirteen other State Universities and Colleges (SUCs) and Higher Education Institutions (HEIs) that included UP Cebu, UP Baguio, UP Mindanao, Ateneo de Naga University, Central Mindanao University, Mapua Institute of Technology, and Visayas State University. The UPLB team, led by Assistant Professor Edwin R. Abucay of CHE- DCERP, was assigned 45 river basins in MIMAROPA region and Laguna.

The duration of the Phil-LiDAR project saw these institutions working simultaneously, each one an integral part of a big network of academic institutions aiming to change the face of Philippine disaster mitigation.

Mapping hazards and risks

Assistant Professor Efraim D. Roxas, also from CHE-DCERP, described Phil-LiDAR 1 in the very simplest of terms. “It’s all about creating maps that can show the hazards and flood risks.” He further explained that these maps can show the susceptibility of an area in terms of flooding. The maps will answer questions such as “If there is 250mm of rainfall for four hours, which specific areas will be flooded? How deep will the flood be?”

All the maps produced by Phil-LiDAR 1 were turned over to the local government units around the river basins. Local government personnel were even trained in using GIS because the flood hazard maps are GIS-based. Turning over the maps meant that the communities can become decision makers themselves instead of just enduring typhoons and other natural disasters.

Dati kasi hindi tayo handa,” former project staff Gillian Inciong, said. “We just respond and adapt when there is already flooding. But because of the Phil-LiDAR 1 project, communities now have the capability and the resources to be proactive.” Back in 2012, during the DREAM Program, the first “rough” flood model of Marikina City in Metro Manila was tested during the onslaught of southwest monsoon rains; the people were warned hours before the flood happened.

If this can happen for the whole country, Filipinos can embrace stability and continuous development even in the face of an approaching disaster.

This was one of the driving forces behind the team of Phil-LiDAR 1. Sir Ef fondly recalls that the LiDAR team would always motivate and inspire themselves especially during the times when they spent long hours in the field. “Laging sinasabi ng mga Research Assistants na ginagawa nila ito para sa bayan.”

Sir Ef shared that the team didn’t endure all the tough times and challenges during data collection just for personal satisfaction. “We did it so we can help create tools for decision making. Once the output of LiDAR is used for local planning and development, it will definitely help in ensuring the safety of the community during disasters.”

“Saving lives,” Sir Ef emphasized, “is the whole idea of Phil-LiDAR 1.”

Braving storms to save lives

In order to gather data for the maps, the UPLB Phil-LiDAR 1 team had to travel to the river basins assigned to them. They had to collect data both during the dry and rainy seasons, and this meant that they have to stay in different provinces for days and weeks. “We had to stay there for three weeks, sometimes even for a month,” Gillian recalls.

Usually, whenever strong rains or typhoons were forecasted, the Phil-LiDAR team can be seen already preparing their equipment and tools. They would often find themselves hoping for rain, even if it meant additional effort and possible risks. After all, the output will make everything worth it.

Unknown to most, members of the UPLB team actually had to undergo rigorous training in order to make sure they were ready for the intensive fieldwork.

The team learned about bandaging, splinting, and lifting in a rescue course. They even had to take a final written and practical exam. Finally, a rescue simulation was conducted wherein the Phil-LiDAR 1 personnel acted as either bystanders and lifters, or victims. They were given a scenario by the trainers—an explosion. The participants had to apply their learnings in order to conduct a successful rescue.

If that wasn’t enough, the team also had to undergo a two-day training on Water Safety and Rescue. Aside from swimming several laps in an Olympic-size swimming pool, they had to undergo rescue simulations to know what to do if a person is drowning, being electrocuted, and even having an epileptic episode. Rope rescue training were also conducted and basic rappelling do’s and don’ts were discussed.

All of these capability building were necessary for the whole UPLB Phil-LiDAR team so that the members are physically and emotionally ready for their upcoming journeys.

In the field, the team measured the changes in the river’s water level using depth gauges and Automated Water Level Sensors (AWLS).

Depth gauges should be submerged in the river for six hours straight or more, depending on the amount of rainfall in the river basin area. That was only one of the reasons why the team’s fieldwork lasted for days. On the other hand, the AWLS were installed on bridges. The AWLS laser pulses project downward to measure water level change at specific time intervals. The team also gathered data on river flow with the use of mechanical flow meters deployed along the different points of the bridge before, during, and after rain events.

Rainfall data was also collected through manual rain gauges stationed within the boundary of the river basin. Locals were hired to monitor these and manually record the rainfall data every 15 minutes.

The UPLB team also had the opportunity to meet lots of people from different backgrounds when they conducted household interviews and surveys. These validation activities were important so that the team can corroborate people’s estimates with actual flood depth and time of rainfall within the river basin.

Sir Ef recalls that fieldwork was an exciting part of the project. Every deployment and scheduled fieldwork was considered an adventure, specially during strong rains and typhoons. There were even some instances wherein the depth gauges were either lost, washed away by floods, or stolen after deployment in the study areas. Though these were eventually retrieved, the gauges turned out to be non-functional and all the recorded data were lost. The team had to borrow additional depth gauges from UP Diliman and other partner SUCs/HEIs and the Oscar M. Lopez Center for Climate Change Adaptation and Disaster Risk Management Foundation, Inc.

Greater than the sum of its parts

When someone mentions the UPLB Phil-LiDAR 1 Project, this is what usually comes to one’s mind: floods, typhoons, maps, and GIS. While all of these are true, the whole project is something much bigger.

“I think it’s a high impact project,” Sir Ef shared. “Because we are all involved in providing LGUs the information and resources to reduce their risks! We do what we do to make sure that these areas are safe, thus we help people become safe.”

The maps have changed the game of climate change adaptation and disaster risk reduction. “Before, it was very black and white. When you say it’s going to flood in a particular region it was either all the areas will experience the flood or none will. There was no way to be specific. With these Phil-LiDAR maps and models, it is now possible to pinpoint the exact area where the flood will occur, and what the effects will be. That will guide communities to decide on where they should evacuate, and where they should focus future developments,” Sir Ef said.

Though the project has come to an end, the future remains promising. The methodology of flood modeling and simulation were well documented, which means that this can be continuously done and replicated. Future researchers don’t have to start from scratch the way that DREAM and Phil-LiDAR did. Sure, there were errors and challenges along the way, but all of those have led to the establishment of best practices which can be applied in future research.

Proactive, not just resilient

Resilience is just one of the many admirable and laudable traits of Filipinos. But we are also inquisitive and we question why things are the way they are. We are creative and we continuously strive to be better.

Yes, we are overcomers, but we are also solution- seekers and problem solvers.

The Phil-LiDAR 1 project has made communities realize that they have a choice—that they are capable of knowing how to act prior to disasters, and that they are no longer confined to waiting out the effects of the flood and just learning how to adapt.

Probably, other than the many tangible accomplishments of the project, Phil-LiDAR’s biggest potential contribution is the empowerment of communities.

As Gillian said, “Kakayanin na nilang tumayo sa sarili nilang paa.” ■