DAVAO CITY (MindaNews / 31 Jan) – Topographic maps generated by light-detection and ranging or LiDAR will be used in flood modeling for disaster risk areas in the Davao region.
The LiDAR-generated maps will have high resolution with 1:2,500 scale, more detailed than the 1:10,000 geohazard maps of the Mines and Geosciences Bureau, said Anthony C. Sales, regional director of the Department of Science and Technology (DOST) 11.
He explained that the topographic maps will show elevations up to barangay level, citing that the “real” terrain can be identified with the three-dimensional (3D) maps of areas.
Among the details are houses, buildings and other infrastructures and vegetation in the area, he cited.
LiDAR mapping of the city and Compostela Valley had been completed, while that of Davao Oriental will follow immediately, he said, adding that the maps will be available before the end of February.
Noting that a LiDAR-generated map will be useful in flood modeling, he said it indicates the path of water from the rivers when they overflow, thus showing areas that will be flooded.
With these maps, he said, “We will know the estimate damage cost of a disaster, including the number of houses that will be affected.”
He cited that there is already a flood modeling, which is a computer-generated simulation, used for the Marikina River.
The Disaster Risk Exposure Assessment for Mitigation-LiDAR is one of the eight components of the DOST’s Project National Operational Assessment of Hazards (NOAH).
Other components of the project are the Distribution of Hydrometeorological Devices in hard-hit areas in the Philippines (Hydromet), Enhancing Geohazards Mapping through LiDAR, Coastal Hazards and Storm Surge Assessment and Mitigation (CHASSAM), Flood Information Network (FloodNET) Project, Local Development of Doppler Radar Systems (LaDDeRS), Landslide Sensors Development Project, and Weather Hazard Information Project (WHIP).
Sales said the Project NOAH is a response to the President’s instructions to put in place a responsive program for flood mitigation, flood early warning system for communities along 18 major river systems, enhancement of geohazard maps, and enhancement of storm surge vulnerability maps.
Launched in 2012, the Project NOAH uses complete data from satellite, LiDAR, water level sensors and automated rain gauges needed for predicting floods, and other impacts of natural calamities, Sales said.
Impacts of a disaster can be predicted five days before landfall using data from the satellite, and 24 hours before landfall with data from Doppler radars, he said in his presentation.
“Doppler radars detect the amount of precipitation a cloud or weather system brings,” he said.
He mentioned that in Mindanao, there are two Doppler radars installed, one in Tampakan, South Cotabato, and the other in Hinatuan, Surigao del Sur, that are integrated into NOAH.
For early warning devices on the ground, he said water level sensors predict disaster risk three to six hours before flooding, while automated rain gauges from six to nine hours before flooding.
Project NOAH aims to install 1,000 water level sensors in 18 critical river basins in the country, including the Davao River, Sales said.
The installation of all sensors is expected to be done this year, he continued, as all areas were already identified.
He mentioned that Mayor Sara Duterte requested for sensor units to be installed at the Davao River, and that Science and Technology Secretary Mario Montejo committed to provide the city.
This year, the Davao River will have a telemetric monitoring system for flood monitoring in the city, according to the Public Safety and Security Command Center here.
Sales said the DOST welcomes requests from local government units for additional automated sensors in areas not identified in the project. (Lorie Ann A. Cascaro / MindaNews)