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Geohazard Mapping: Buy and build at your own risk

Whether you intend to buy a house or a lot, it wouldn’t hurt to see the geohazard map by the Mines and Geosciences Bureau (MGB) to assess if your place is prone to natural disasters like flood or landslide. Such an advice not only goes to prospective buyers, but also to real estate developers, according to Secretary Ramon J. P. Paje of the Department of Environment and Natural Resources (DENR) in a statement released on the agency’s website last Friday.

He said, “We strongly advise prospective buyers of land properties for housing or other infrastructure projects to refer to the geohazard maps to make sure that the lots they are intending to buy are not situated in landslide- and flood-prone areas.”

MGB has identified the top ten flood-prone sites as Bulacan, Ilocos Norte, Maguindanao, Metro Manila, North Cotabato, Oriental Mindoro Nueva Ecija, Pampanga, Pangasinan, and Tarlac, while the top ten landslide-prone areas are Abra, Benguet, Catanduanes, Cebu, Ifugao, Kalinga-Apayao, Marinduque, Mountain Province, Nueva Ecija, and Southern Leyte.

Flood-prone and landslide-prone sites are nonetheless manageable given the proper approach. The DENR asserted that lot owners and real estate developers may consult experts for appropriate engineering interventions, architectural techniques, and many other building construction technologies to keep the area under control. After all, it is always advisable to keep risks manageable, especially when it comes to long-term investments.

“Buying a house and lot is definitely a big investment for an ordinary family; that they have to pay at the most, for 30 years, if they acquire such through a housing loan.  Finding out that their area gets easily flooded and prone to landslide later on would be tragic, so it is better to be on safe side always,” Paje said as a reminder to the public when purchasing real estate properties.

Geohazard mapping project

So what is the geohazard mapping and assessment program all about?

The DENR website said that this is “an important component of the government’s risk reduction and disaster management program.”

According to, Dr. Karlo Queano, supervisor science research specialist from the Geological Database Information System, revealed that geomaps in the Philippines have already been completed in December 2010.

Geohazard mapping does not only warn residents of vulnerability to flood and landslides, it also identifies sites prone to earthquake, liquefaction, and other forms of ground instabilities. The project is also expected to help generate effective development plans within the safe zones. Fair enough, it can spot settlement sites that might be affected by natural disasters.

The DENR-MGB geohazard project works hand in hand with other government agencies for better implementation. As a matter of fact, it seeks the cooperation of Local Government Units (LGUs) to closely monitor high-risk barangays and enforce necessary measures accordingly.

Early last year, DENR has also collaborated with the Department of Education (DepEd) to incorporate disaster risk reduction in school curriculum as part of its information dissemination campaign, according to

Department of Science and Technology, meanwhile, was asked to develop a teacher’s module that shall be employed by DepEd.

Geohazard maps on the web

Geohazard maps are currently accessible online through various government websites such as the DENR (, MGB (, Environmental Science for Social Change (, and Philippine Information Agency (

Consequently, geohazard copies are also available in local government units across the country for easy public reference.

Paje further said that maps for 1,634 cities and municipalities in the Philippines are readily downloadable in 1:50,000 scale (reflecting 1cm per 500m), although some have doubted the reliability of these materials.

Meanwhile, Editha Amiscaray, an official at Provincial Environment and Natural Resources Office (PENRO) in Negros, revealed at the Negros Chronicle in June 2012 that the current geomaps employed by local government units might not be reliable. Geomaps for the province might be poorly done since these were only completed in a span of one month, she said.

With the growing concern on the reliability of geomaps, the government came up with the 1:10,000 scale (suggesting 1cm per 100m). Amiscaray disclosed in the GreenWatch Philippines, Inc. forum that detailed geomap versions for Sibulan, San Jose, Valencia, and Dumaguete City are underway and are likely to manifest increased levels of accuracy and reliability.

There is no doubt that Negros has all the rights to demand for accurate and reliable geohazard mapping. Recall that the northern portion of the province suffered from the horrific aftermath brought about by the 6.9 magnitude quake on February 6, 2012. The earthquake left the area with Php1.2 billion worth of infrastructural damage, along with over 50 casualties.

Detailed geohazard maps for Central Visayas shall be made available by 2014. In a Manila Bulletin news report, Region 7 Mines and Geosciences Bureau announced that the maps are about to cover Negros Occidental and Cebu provinces although priority areas were already named as follows: San Jose; Valencia; Simbulan; and Dumaguete City.

Geomapping soon in 3D

Three-dimensional geomaps of the Philippine topography are also in the works courtesy of Nationwide Operational Assessment of Hazards (NOAH). 3D-mapping activity shall likely commence on September 17 upon the arrival of the Light Detection and Ranging (LIDAR) equipment.

The LIDAR equipment, worth Php200-million from Ontario, Canada, promises accurate and reliable data through high-resolution land mapping operation and low-resolution underwater mapping operation (as deep as 12ft). Underwater surveillance is made possible by the bathymetric component of the equipment.

The Science and Technology Information Institute is currently conducting a training on how to operate the LIDAR equipment. The training is being held at the Academy of Science and Technology Institute in UP Diliman.

In an interview with Manila Bulletin News, Dr. Enrico Paringit, head of the 3D Mapping and Flood Modelling Project, confirmed his participation in the two-week ASTI training for LIDAR operation.

Project NOAH on top

3D Mapping and Flood Modelling is only one of the many components of the Department of Science and Technology (DOST) under project NOAH. Other components are hydromet distribution in high-risk areas, geohazards mapping enhancement, coastal erosion controls, flood information network, local doppler radar system development, landslide sensors development, and weather hazard information.

Based on the Official Gazette account, ”Project NOAH is the Department of Science and Technology’s (DOST) response to the call of President Benigno S. Aquino III for a more accurate, integrated, and responsive disaster prevention and mitigation system, especially in high-risk areas throughout the Philippines.”

Project NOAH is likely to collaborate with many different government and non-government agencies to promote better disaster management as well as prevention capacity through the use of advanced science and technology.

According to a Philippine Star report, President Benigno Aquino III launched Project NOAH in July, which is considered the “Disaster Consciousness Month,” when the European Commission gave away 35 million Euros for the Philippine Disaster Preparedness Program.