Scientist presses probabilistic map use for LGU plans

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QUEZON CITY – A multi-hazard map is more important than single hazard ones in saving lives and averting disasters, said a multi-awarded Filipino scientist during his lecture for the towns of Catarman and Capul, Northern Samar.

Mahar Lagmay, geologist and executive director of University of the Philippines, Resilience Institute (UPRI) with Nationwide Operational Assessment of Hazards (NOAH) as its core, was resource speaker for the 3-day training workshop (Sept. 6-8, 2017), for the formulation of Community Climate Vulnerability and Disaster Risk Assessment in preparation for Barangay Contingency and Adaptation Plan (CCVDRA-BCAP) of 55 barangay captains of Catarman, 12 barangay captains of Capul towns together with their ABC Presidents and municipal technical managers.

The event, being conducted in series of batches, is hosted by the Local Climate Change and Adaptation for Development (LCCAD) in partnership with the UPRI, 2nd Congressional Office of Rep. Joey Sarte Salceda, the Special Committee on Climate Change of the House of Representatives headed by Ako Bikol Partylist Rep. Christopher S. Co, City Mayor Noel Rosal of Legazpi and Albay 3d Rep. Fernando V. Gonzalez and the Philippine Information Agency (PIA-5) led by Regional Director Aida A. Naz.

LCCAD executive director Manuel Rangasa said that the event is in response to the call of Pres. Rodrigo Roa Duterte to mainstream Climate Change Adaptation (CCA) and Disaster Risk Reduction and Vulnerability Reduction (DRVR) into local development planning processes and the country’s commitment to the Paris Agreement, aside from being input to House Bill 6075 which will enact a new law creating the Department of Disaster Resilience under the sponsorship of Salceda.

Lagmay cited the important aspects of effective disaster prevention and mitigation noting the responsibility of the government in giving warning, the response of the people, and the use of appropriate hazard maps.

“It is the responsibility of the government to deliver accurate, readily accessible, understandable and timely warnings. However, no amount of warning will work or will be effective if hazard maps are inappropriate,” he said.


Hazard mapping and risk assessment

Lagmay presented the deterministic and probabilistic types of hazard maps used by the government in depicting hazard scenarios and executing DRR plans. Deterministic type is based mainly on history and the people’s experience which might make it inaccurate in predicting disasters. Probabilistic type on the other hand relies on scientific evidence in assessing risk by simulating future multiple scenarios of disasters such as flood, storm surges and landslides.

“While historical losses can explain the past, they do not necessarily provide a good guide to the future; most disasters that could happen have not happened yet. Probabilistic risk assessment simulates those future disasters which, based on scientific evidence, are likely to occur. As a result these risk assessments resolve the problem posed by the limits of historical data,” he explained.

Lagmay cited the thousands of people killed and properties ruined due to use of inaccurate maps such as during the onslaught of typhoon Pablo in Compostella Valley in 2012 and Supertyhoon Yolanda in Tacloban, Leyte, where evacuation centers were constructed in disaster prone areas killing people right at the evacuation centers where they supposedly seek refuge.

“In Compostella Valley, 566 people heeded warnings by seeking refuge in an evacuation center but it became their grave when debris flow overwhelmed the site,” he said.

“Another example is the Yolanda disaster where 70 percent of evacuation centers in Tacloban were inundated by storm surges, which only tells us that the storm surge hazard maps were erroneous if they were used in the city’s disaster mitigation plan,” Lagmay furthered.

Lagmay said deterministic type was used in those times because it was only recently that government invested in technologies that permitted the creation of probabilistic maps.

Moreover, it was in 2012 when the government invested on hazard maps using frontier science and advanced technology to map out the Philippine landscape at very high resolution.

With this map, he noted, safe and hazard prone areas can accurately be identified to build a well-planned and resilient community against disasters. “During disasters, it is very important to see not only the danger zones but also the safe areas because these are the sites where you relocate people and develop places that are out of harms way,” he said.


Hazard maps available for public use

Lagmay said that the availability and accessibility of near-real time data via android platforms provided people with more accurate information allowing them to response appropriately and save lives like what happened during Habagat Flood in Marikina with zero-death, Ruby Storm Surge in 2014 despite massive number of houses destroyed and succeeding events.

Lagmay said that maps are available at and in an award-winning mobile app called Arko. The NOAH maps are distributed to empower local government units (LGUs) and individuals,” he said.

Lagmay noted that by knowing the hazards in their neighborhood, people are made aware of the dangers in their community – the first step in effective disaster preparedness and mitigation.

Moreover this entails long term education and rooting of culture of safety and preparedness in communities along with the standardization of national CCA-DRVR program. (RMN) ##

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