Improvement of Hazard Assessment and Management in the Philippines

Transcription

1 Improvement of Hazard Assessment and Management in the Philippines (2014 Summer Training Course for Slope Land Disaster Reduction) Ian Alejandrino (Philippines) Nguyen Manh Hieu (Vietnam)

2 Presentation Outline Introduction Present Disaster Risk Reduction Management Efforts Landslide Susceptibility/Hazard Mapping Rooms for improvement

3 Introduction Population - About 100 million people, the Philippines is the seventhmost populated country in Asia and the 12th most populated country in the world. - An additional 12 million Filipinos live overseas Climate - Tropical maritime climate - Rainy season from June to November - Annual rainfall measures as much as 5,000 millimeters (200 in) in the mountainous east coast section but less than 1,000 millimeters (39 in) in some of the sheltered valleys.

4 Disasters in Philippines

5 Seismicity Map to March 2012 Source: United States Geological Survey s (USGS)

6 Disasters in Philippines Typhoons: The Philippines is the most-exposed large country in the world to tropical cyclone. Annually, around 19 tropical cyclones or storms enter the Philippines In modern meteorological records, the deadliest storm was Typhoon Haiyan, which became the strongest landfalling tropical cyclone ever recorded on November 7-8, The wettest known tropical cyclone to impact the archipelago was the July 14 18, 1911 cyclone which dropped over 2,210 millimetres (87 in) of rainfall within a 3-day, 15-hour period in Baguio City.

7 Records of the deadliest typhoons in Philippine history

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9 Superimposed tracks of typhoons that entered PAR from

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11 Floods in the Philippines Aug. 8, 2012, flooding around Bulacan, north of Manila, Philippines. (dnd/afp/gettyimages) Evacuation in Malina, Philippines 2012

12 Landslides in the Philippines Benguet, Philippines after Parma typhoon in 2009

13 Soldiers and volunteers search for bodies following a landslide caused by heavy rains in Barangay Cawag, Subic, Zambales (2013)

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16 MGB expert s checklist produced hazard map

17 Present Disaster Risk Reduction Management Efforts Initially the Philippines does a responsive approach in hazard management. In July 6,2012,the Philippines launched the DOST Project NOAH in response to the call of the president for a more accurate, integrated, and responsive disaster prevention and mitigation system, especially in high-risk areas throughout the Philippines.

18 Components of Project NOAH Hydromet- A total of 600 automated rain gauges (ARG) and 400 water level monitoring stations (WLMS) will be installed along the country s 18 major river basins DREAM-LIDAR- aims to produce more accurate flood inundation and hazard maps in 3D for the country s flood-prone and major river systems and watersheds using LIDAR technology. CHASSAM- generate wave surge, wave refraction, and coastal circulation models to understand and recommend solutions for coastal erosion.

19 Hydromet Sensors

20 Components of Project NOAH FloodNET- come up with computer models for the critical RBs, automate the process of data gathering, modeling and information output, and release flood forecasts. WHIP- involves the utilization of platforms such as television (DOSTv) and a web portal ( which display real-time satellite, Doppler radar, ARG, and WLMS data to empower LGUs and communities to prepare against extreme natural hazards. LaDDeRS- seeks to develop local capacity to design, fabricate, and operate sub-systems of Doppler radars for remotely sensing the dynamic parameters of sea surface such as wave, wind field, and surface current velocity.

21 Components of Project NOAH Landslide Sensors Development Project- a low-cost, locally developed, sensor-based early monitoring and warning system for landslides, slope failures, and debris flow. Enhancing Geohazards Mapping through LIDAR and Other High Resolution Imageries- shall use LIDAR technology and computer-assisted analyses to identify exact areas prone to landslides.

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23 Landslide Inventory Based on satellite imagery dated from Used to verify the accuracy/acceptability of the simulated results

24 Landslide Inventory Map of the Philippines ARMM Region Region 12 9% 1.0 8% Region 11 Region 10 Region 9 Region 8 Region 7 Region 6 Region 5 Region 4-B Region 4-A Region 3 Region 2 Region 1 CAR Landslide Inventory of the Philippines 0.14% ( ) 1.74% % % % 4.00% 4.21% % % 478 Total no. of landslides as of January 2014: % % 13.17% NO. OF LANDSLIDES 18.50% 18.53% - 85% of the country has available satellite images for inspection. - High-res images such as Pleiades, Worldview, Quickbird, DigitalGlobe and Landsat were used.

25 Landslide Inventory Map of Brgy. Buguias, Benguet Landslide Inventory per barangay of Buguias, Benguet Poblacion Loo Calamagan Bangao Amgaleyguey NO. OF LANDSLIDES 25 Total no. of landslides from : 62 Landslides in Brgy. Lengaoan

26 Landslide Inventory Suggestions for improvement: Creation of a event based inventory after every disaster (with field validation) Compile them to form a multi temporal landslide inventory with sufficient information Differentiate the source from the deposit Use of satellite imagery techniques to delineate landslides

27 Rainfall Induced Shallow Landslide Using SINMAP ( a toolbar in ArcGIS) Based on infinite slope model Accepts a range of input parameters to create a landslide susceptibility map (cohesion, angle of friction, topographic wetness index, soil density)

28 SRTM (90m) SAR (10m) IfSAR (5m)

29 Rainfall Induced Shallow Landslide

30 Rainfall Induced Shallow Landslide Problems: Probability of landslide for a certain event is not calculated Effects of vegetation are not considered Proposed Solution/Suggestions for improvement: Produce a local threshold. (combination of the susceptibility rating and the rainfall intensity/duration through the use of a single event landslide inventory) Installation of sensors to obtain pore water pressure for monitoring landslides in high priority areas Research more on the effects of vegetation on infiltration and root cohesion Try to simulate the extent of a landslide event (deposition area)

31 Debris-Flow Using Flo-2D software The extent of the debris flow is determined by the alluvial fan extent Rainfall Intensity Duration Frequency as input for a scenario based output There are 857 identified and validated on site potential debris flow torrents in the Philippines

32 Alluvial Fan (Casiguran, Aurora)

33 Debris-Flow

34 Debris-Flow

35 Debris-Flow Problems: Flow-2D is a flood modeling software Does not take into account the volume of debris No particular threshold for warning Proposed solution: Try to use debris 2D to account for the volume of possible debris To create different scenario maps for different rainfall return periods To establish a local threshold for warning

36 Structurally Controlled Landslides Using Matterocking and Coltop 3D Identifies possible structurally controlled landslide failure sites with the aid lineaments and faults

37 Structurally Controlled Landslides

38 Structurally Controlled Landslides

39 Structurally Controlled Landslides Suggestions for improvement: Use of LIDAR images to determine possible zones for deep seated failure

40 Room for improvements and other possible problems that need to be addressed The weather bureau in the Philippines give to little and broad (area) information. (no rainfall amount predictions and very simple interpolations are used for the contours). Education seminars only reach up to the municipal level. Mostly the engineers and the government officials are the only ones who participate in this event. A database on the socio-economic factors in every area will help in decision making Collaborative works with other countries will prove to be of great help.

41 Thank You! Maraming salamat po! Xin cam on!