SUMMARY REPORT

RESULT OF THE MGB GEOHAZARD ASSESSMENT COVERING TWELVE (12) MUNICIPALITIES/CITY IN THE PROVINCE OF

In line with the recent Presidential Directive and NDCC resolutions following the February 17 Southern Leyte landslide incident, and the need to fast track the geohazard mapping program along the eastern seaboard of the , geologists from the Mines and Geosciences Bureau-Regional Office III (MGB-R3) conducted a geohazard assessment of the barangays in the municipalities/city in the province of Bataan.

Each was classified according to their susceptibility to landslide and/or flooding. For landslide susceptibility, the rating parameters are as follows:

High • Presence of active and/ or recent landslides • Presence of numerous and large tension cracks along slope adjacent to the community and that would directly affect the community • Areas with drainages that are prone to landslides damming • Steep/Unstable slopes consisting of loose materials

Moderate • Areas with indicative and/or old landslides • Presence of small tension cracks along slope and are located away from the community • Moderate slopes

1 Low • Low to gently sloping • No presence of tension cracks

Each barangay was rated into low, moderate or high for flooding susceptibility with the rating parameters as follows:

Low • 0 – 0.5 meter depth of floodwaters

Moderate • 0.51 – 1 meter depth of floodwaters

High • > 1 meter depth of floodwaters

With regards to landslide susceptibility, the barangays assessed include areas that are located on and/or near slopes and riverbanks and have the potential for landslide occurrence. The rating of each barangay presented herein particularly refers to the barangay proper since majority of the population is located there. It should be noted, however, that the rating does not necessarily reflect those of the . These barangays were presented with a Landslide Threat Advisory informing their susceptibility to landslides and the corresponding recommendations particular to the barangay.

The flood susceptibility of the barangays in the municipalities/cities was also assessed. Barangays classified with moderate to high susceptibility to flooding are located in identified low portions of the barangay, in topographically low-lying areas and/or near a major river system. These barangays were presented with a Geohazard Threat Advisory informing their susceptibility to flooding and the corresponding recommendations particular to the barangay.

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Table 1. Number of Assessed Barangays

Municipali ty/City Total Barangays Number of Assessed Barangays 1. 9 9 2. 14 14 3. City of Balanga 25 25 4. 46 46 5. Hermosa 23 23 6. 12 12 7. 18 18 8. Morong 5 5 9. 29 29 10. Orion 20 20 11. Pilar 19 19 12. Samal 14 14

TOTAL 234 234

SUMMARY OF THE ASSESSMENT:

1. Municipality of Abucay

• In terms of landslide susceptibility, one (1) barangay has a low to moderate susceptibility to landslides (Bangkal). The barangay is located in a rolling to hilly portion of the municipality, moderately steep slopes and with tension cracks far from the community. Creeping is also observed.

• There are two (2) barangays with low to moderate susceptibility to flooding (Mabatang and Omboy). The barangay proper has a low susceptibility to flooding.

• There are two (2) barangays (Calaylayan and Capitangan) with moderate susceptibility to flooding. It is located near the river where avulsion and overflow is possible, occurrence of high tide and improper waste disposal in the river system constricting the natural drainage.

• There are four (4) barangays (Gabon, Laon, Salian and Wawa) having a moderate to high susceptibility to flooding in most areas of the barangay.

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2. Municipality of Bagac

• In terms of landslide susceptibility, there are eight (8) barangays in Bagac that have potential for landslide occurrences (Binuangan, Saysain, Ibis, Binukawan, San Antonio, Parang, Quinawan and Paysawan). The barangay propers have low susceptibility to landslides. The road cuts and generally high and mountainous areas have a moderate to high susceptibility to landslides.

• Most of the nine (9) barangays (Binuangan, Saysain, Bagumbayan, A. Ricardo, Ibaba, Pag-asa, Binukawan, Parang and San Antonio) have low susceptibility to flooding in the barangay proper and most areas of the barangay. The following barangays have areas and portions of the barangay and coastal zones with moderate to high susceptibility to flooding.

• There are five (5) barangays with low susceptibility to flooding in most areas but with portions of the barangay that are generally low-lying and with portions near major rivers, creeks and coastal areas that have moderate to high susceptibility to flooding (Ibis, Tabing Ilog, Banawang, Quinawan and Binukawan).

3. City of Balanga

• In terms of landslide susceptibility, there are four (4) barangays in Balanga that have potential for landslide occurrences (Cabog-Cabog, Tanato, Dangcol and Munting Batangas). The barangay propers have low susceptibility to landslides. The road cuts and generally high and mountainous areas have a moderate to high susceptibility to landslides.

• There are nine (9) barangays with low susceptibility to flooding in most areas of the barangay (Cabog-Cabog, Tanato, Dangcol, Munting Batangas, T. Camacho, Bagong Silang, Talisay, Tenejero and Ibayo).

• There are nine (9) barangays with low susceptibility to flooding in most areas but with portions of the barangay that are generally low-lying and with portions near agricultural areas and major rivers and creeks that have moderate to high susceptibility to flooding (Tuyo, Bagumbayan, Puerto Rivas Lote, Doña Francisca, Cupang West, Cupang Proper, Central, and San Jose).

• One (1) barangay has a low to moderate susceptibility to flooding (Cupang North). The portion subject to flooding is located near the confluence of the rivers.

4 • There are five (5) barangays with moderate to high susceptibility to flooding (Tortugas, Puerto Rivas Itaas, Puerto Rivas Ibaba, Sibacan and Malabia). These barangays are affected with flooding from the release of excess waters from the dam, overflow from the river, tide changes and structurally controlled such as upgraded roads.

• Flooding in one (1) barangays (Cataning) is controlled by topography. The barangay has different flood levels and susceptibility to flooding.

4. Municipality of Dinalupihan

• In terms of landslide susceptibility, six (6) barangays in Dinalupihan that are located at a generally high elevation has low landslide susceptibility (Bangkal, Naparing, Pita, Payangan, Roosevelt and San Pablo) particularly in the barangay proper.

• Two (2) barangays (Happy Valley and Bayan-Bayanan) has a moderate to high susceptibility to landslides especially along the road cuts. The barangays had a past history of landslide occurrence. There are no communities directly affected by the landslides. • There are eighteen (18) barangays with low susceptibility to flooding (Bangkal, Bonifacio, Burgos, Del Pilar, Dalao, Kataasan, Mabini Proper, Pag-asa, Pita, Roosevelt, San Pablo, Aquino, Maligaya, Payangan, Pentor, Tubo-Tubo, Payumo and Zamora).

• There are six (6) barangays with low to moderate susceptibility to flooding. Factors to flooding include constricted creek/river channel, excessive surface runoff coming from areas of higher elevation, flash floods, overflow from the creek/river, blocked natural channels, inadequate drainage system and terrain controlled (Pagalanggang, Sto. Niño, Sapang Balas, Gomez, Happy Valley and Mabini Extension). • There are four (4) barangays with low, moderate to high susceptibility to flooding. The barangays have naturally high and low-lying areas, hence, floodwater flows towards the low-lying areas of the barangay (New San Jose, Old San Jose, Rizal and Roxas). • Two (2) barangays (San Simon and Gen. Luna) have moderate susceptibility to flooding. Flooding is usually caused by overflow from the river in San Simon and possible effect of the construction of the SCTEX in the case of Gen. Luna. • There are eleven (11) barangays with moderate to high susceptibility to flooding. These barangays had experienced historical high level flood usually associated with naturally low elevation, overflow from creeks/rivers, restricted flow of the river due to blocked natural channels, water impoundment structures and

5 inadequate drainage (Colo, Layak, Magsaysay, Naparing, Pinulot, Saguing, San Benito, Tucop, Padre Dandan, San Isidro and Torres). • There are four (4) barangays with high susceptibility to flooding (Daang Bago, Luacan, San Ramon and Sta. Isabel). Factors contributing to flood events include beaching of the dike protecting the rivers, back flooding, and floodwater coming from the highlands, siltation and poor drainage system. • Siltation and riverbank erosion along unprotected portions of the creek/river is evident along the active creek and river channels in Dinalupihan and nearby municipalities. The creeks/rivers that traverse the municipality and influence flooding include Naparing, Pagalanggang, Pinulot, San Benito and Dila-dila creeks and Balsic, Layak, Pasig and Pentor rivers. • There are barangays in the vicinity of the Subic-Clark- Expressway (SCTEX) that are affected by the structure. The effects of the SCTEX alignment should be monitored so that proper mitigating measures could be provided (Sta. Isabel, Aquino, Gen. Luna, Kataasan, New San Jose, San Ramon and Sto. Niño).

5. Municipality of Hermosa

• In terms of landslide susceptibility, the four (4) barangays in Hermosa that are located in a generally high elevation has a low landslide susceptibility (Sumalo, Pandatong, Tipo and Sacrifice Valley);

• There are eight (8) barangays with low susceptibility to flooding (Culis, Mabiga, Mambog, Pandatong, Sumalo, Tipo, Judge Roman Cruz, Sr. [Mandaman], Sacrifice Valley)

• One (1) barangay (San Pedro) has a low to moderate susceptibility to flooding. Most of the residential area has low flooding susceptibility. Agricultural areas of the barangay and those located near the river channel have moderate susceptibility.

• There is one (1) barangay (Cataning) with low, moderate to high susceptibility to flooding. The barangay has naturally low-lying areas; road portions of the barangay had been elevated hence, floodwater flows towards the low-lying areas of the barangay.

• There are eight (8) barangays with moderate to high susceptibility to flooding. These barangays have portions adjacent to active creeks and river channel, and has naturally low-lying areas. Breaching of dikes protecting the riverbanks is also a factor of flooding in the barangays (Bacong, Balsic, , Maite, Palihan, Pulo, Saba and Sto. Cristo.

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• There are five (5) barangays with high susceptibility to flooding (A. Rivera, Almacen, Burgos-Soliman, Daungau and Mabuco). Factors contributing to flood events include beaching of the dike protecting the rivers, back flooding, high tides coinciding with heavy precipitation and floodwater coming from the highlands, storm surges, sitlation and poor drainage system.

• Siltation and riverbank erosion along unprotected portions of the creek/river is evident along the active creek and river channels in Hermosa and nearby municipalities. The creeks/rivers that traverse the municipality and influence flooding include Mambog, Baloc, Layak, Hermosa, Almacen, Caulaman, Tama, Sto. Cristo, Cataning, Colo, Baruya, Tavio, Paluka and Quirong rivers.

• The barangays in the vicinity of the Subic-Clark-Tarlac Expressway (SCTEX) are Bacong, Bamban, Maite, Palihan, Tipo and Sacrifice Valley. The effects of the SCTEX alignment should be monitored so that proper mitigating measures could be provided.

6. Municipality of Limay

• Barangays with slopes and has a low susceptibility to landslides include Lamao, Alangan, Reformista, St. Francis de Asis, St. Francis of Assisi II and Duale. The mountainous areas have a moderate to high susceptibility to landslides especially along the road where erosion surfaces are present.

• All the twelve (12) barangays (Kitang I, Lamao, Alangan, Townsite, Landing, Barrio Luz, Wawa, Reformista, Poblacion, St. Francis de Asis, St. Francis of Assisi II and Duale)) have low susceptibility to flooding in the barangay proper and most areas of the barangay.

• Portions of the barangays experiencing localized flooding are located neara active river and creeks and in identified low-lying and agricultural areas of the barangay, Barangays along the coastal areas are susceptible to storm surges (Landing, Barrio Luz, St. Francis de Asis, St. Francis of Assisi II and Wawa).

• Riverbank erosion was observed in the active creeks/river and natural channels traversing the municipality such as Mamala River, Duale River and Lamao River.

• The release of excess water from the dam in So. Tikip may contribute to localized flooding especially in the agricultural areas.

7 7. Municipality of Mariveles

• In terms of landslide susceptibility, most of the barangays in Mariveles have that are located on and/or near slopes and have the potential for landslide occurrence. However, most of the populated areas of the barangays have low landslide susceptibility due to the massive nature of the rock.

• Two (2) barangays has a low to moderate susceptibility to landslides. In Brgy. Baseco, there are newly opened slopes showing deeply weathered characteristics. In Brgy. Biaan, there had been a minor landslide occurrence near the barangay proper.

• One (1) barangay (Maligaya) has a moderate to high susceptibility to landslides. There had been a recent mass movement along the slopes where there is a vulnerable community. Also, a road segment in the zigzag road is an active landslide area.

• One (1) barangay (Ipag) has a moderate susceptibility to landslides especially in the mountainous sitio where there are presence of kaingin slopes. There are no communities directly affected by the landslides. • There are nine (9) barangays with low susceptibility to flooding (Alasasin, Mt. View, Townsite, Lucanin, Batangas II, Alion, Baseco, Malaya and Sisiman). Localized flooding are expected in portions that are located in a naturally low- lying portion of the barangay and the coastal areas. • There is one (1) barangay (Cabcaben) with low to moderate susceptibility to flooding. Factors to flooding include flash floods, overflow from the creek/river and possible breaching of a man-made water impoundment. • There are two (2) barangays with low, moderate to high susceptibility to flooding. The barangays have naturally high and low-lying areas hence, floodwater flows towards the low-lying areas of the barangay (Maligaya and Ipag). • There are five (5) barangays with moderate to high susceptibility to flooding. Flooding is usually caused by overflow from the river, backflooding, excessive surface run off from areas of higher elevation, drainage problem and urban development. • There is one (1) barangay with high susceptibility to flooding. This barangay had experienced historical high level flood usually associated with naturally low elevation, overflow from creeks/rivers, restricted flow of the river due to blocked natural channels, constricted river system due to urban development, and poor and inadequate drainage. • Siltation and riverbank erosion along unprotected portions of the creek/river is evident along the active creek and river channels in the municipality. The creeks/rivers that traverse the municipality and influence flooding include Agripa Creek, Pangulisanin, Amo, Lucanin, Santol, Bulok, Balon, San Isidro, Biaan, Talain and Lusong rivers.

8 • The coastal barangays are vulnerable to storm surges and possible tsunami hazards.

8. Municipality of Morong

• The mountainous areas have moderate to high susceptibility tolandslides. The road cuts and road sections where erosion surfaces are present also have moderate to high susceptibility to mass movement.

• All the five (5) barangays (Poblacion, Binaritan, Mabayo, Sabang and Nagbalayong) have low susceptibility to flooding in the barangay proper and populated centers.

• Portions of the barangays experiencing localized flooding are located near active rivers and creeks and in identified low-lying and agricultural areas of the barangay, Barangays along the coastal areas are susceptible to storm surges and coastal flooding.

• Riverbank erosion was observed in the active creeks/river and natural channels traversing the municipality.

• The release of excess water from the dam in So. Tikip may contribute to localized flooding especially in the agricultural areas.

9. Municipality of Orani

• In terms of landslide susceptibility, the two (2) barangays in Orani that are located at a generally high elevation has low landslide susceptibility (Tala and Sibul) particularly in the barangay proper. The road segment connecting the two barangays has a moderate to high susceptibility. There are no communities directly affected by the landslides along this road segment.

• There are ten (10) barangays with low susceptibility to flooding (Apollo, Centro I, Doña, Pagasa, Parang Parang, Tagumpay, Tapulao, Talimundok, Tala and Sibul.

• There are four (4) barangays with low to moderate susceptibility to flooding. Factors to flooding include constricted creek/.river channel, excessive surface runoff coming from areas of higher elevation, overflow from the creek/river, blocked natural channels, inadequate drainage system and terrain controlled (Calero, Tugatog, Kaparangan and Maria Fe).

9 • There are four (4) barangays with low, moderate to high susceptibility to flooding. The barangay has naturally high and low-lying areas, hence, floodwater flows towards the low-lying areas of the barangay (, Bayan (70% low), Paraiso and Mulawin [where the populated area has a moderate to high susceptibility and the barangay to be the first to be inundated]).

• One (1) barangay (Pantalang Bago) has a moderate susceptibility to flooding. Flooding is associated with unusually high tide levels. The road and the port area had been elevated. The barangays is located near the Orani Channel.

• There are seven (7) barangays with moderate to high susceptibility to flooding. These barangays had experienced historical high level flood usually associated with naturally low elevation, high tide coinciding with high precipitation, backflooding, overflow from creeks/rivers, restricted flow of the river due to blocked natural channels and inadequate drainage (Balut, Pacar, Palihan, Pantalang Luma, Wawa, Tenejero, Centro II and Silahis).

• There are two (2) barangays with high susceptibility to flooding (Puksuan and Kabalutan). Factors contributing to flood events include beaching of the dike protecting the rivers, back flooding, high tides coinciding with heavy precipitation and floodwater coming from the highlands, storm surges, siltation and poor drainage system.

• Siltation and riverbank erosion along unprotected portions of the creek/river is evident along the active creek and river channels in Orani and nearby municipalities. The creeks/rivers that traverse the municipality and influence flooding include Calero, Puksuan, Tapulao creeks and Paquing, Mulawin, Tagumpay, Tama and Layak rivers and the main Orani Channel. The eruption of Mt. Pinatubo was one of the factors of siltation of the river channels.

10. Municipality of Orion

• There are nine (9) barangays with low susceptibility to flooding (Arellano, Bantan, Capunitan, Daan Bilolo, Daan Pare, Putting Buhangin, , Sta. Elena, Sto. Domingo and Wawa). There are three (3) barangays with the barangay proper having a low susceptibility to flooding but with low lying areas and agricultural areas with moderate to high susceptibility to flooding (Bagumbayan, Bilolo and San Vicente).

• There are seven (7) barangays (Balagtas, Camachile, Daan Bago, Lati, Lusungan, Villa Angeles and Wakas) with low to moderate susceptibility to flooding. It is located near the river where avulsion and overflow is possible, occurrence of high tide and improper waste disposal in the river system constricting the natural drainage.

10 • There is one (1) barangay (Sabatan) having a moderate susceptibility to flooding in most areas of the barangay.

• There are two (2) barangays (Calangusan and Gen. Lim) having a moderate to high susceptibility to flooding in most areas of the barangay.

• There is one (1) barangay (Balut) having a low, moderate to high susceptibility to flooding controlled by the topography.

11. Municipality of Pilar

• In terms of landslide susceptibility, there are three (3) barangays in Pilar that have potential for landslide occurrences (Diwa, Pantingan and Liyang). The barangay propers have low susceptibility to landslides. The road cuts and generally high and mountainous areas have a moderate to high susceptibility to landslides. Brgy. Pantingan has a moderate to high susceptibility to landslide; Brgy. Liyang has a low to moderate susceptibility to landslide; and Brgy. Diwa has a low susceptibility to landslide.

• There are six (6) barangays with low susceptibility to flooding in the barangay proper and most areas of the barangay (Panilao, Bagumbayan, Bantan Munti, Wakas North, Ala-Uli and Liyang).

• There are nine (9) barangays with low susceptibility to flooding in most areas but with portions of the barangay that are generally low-lying and with portions near major rivers and creeks that have moderate to high susceptibility to flooding (Sta. Rosa, Del Rosario, Rizal. Wawa, Poblacion, Burgos, Nagwaling, Diwa and Wakas South)).

• There are two (2) barangays with moderate to high susceptibility to flooding (Landing and Pantingan).

• There are two (2) barangays with low, moderate to high susceptibility to flooding controlled by the topography (Balut I and Balut II).

12. Municipality of Samal

• In terms of landslide susceptibility, Brgy. Palili has a potential for landslide occurrence and has a low to moderate susceptibility as assessed. The barangay proper has low susceptibility to landslides. The road cuts, river banks and

11 generally high and mountainous areas have a moderate susceptibility to landslides.

• There are three (3) barangays with low susceptibility to flooding in most areas of the barangay (Palili, Imelda and Gugo).

• There are two (2) barangays with low susceptibility to flooding in the barangay center but with portions of the barangay that are generally low-lying, coastal location, with portions near agricultural areas and major rivers and creeks that have moderate to high susceptibility to flooding (Tabing Ilog and West Daang Bato).

• One (1) barangay has a low, moderate to high susceptibility to flooding as controlled by the topography (Lalawigan).

• There are five (5) barangays with moderate to high susceptibility to flooding (San Roque, East Calaguiman, West Calaguiman, Ibaba and San Juan). These barangays are affected with flooding from the overflow from the river, tide changes and storm surges and excessive surface runoff coming from barangays with higher elevation.

• There are three (3) barangays (Sta. Lucia, Sapa and East Daang Bato) with high susceptibility to flooding. The barangays are located in the coastal areas and traversed by major rivers exiting towards the Bay.

It should be noted that these susceptibility ratings were arrived at as of this field assessment. However, the rating could advance (e.g., from low to moderate, and moderate to high) based on the present and historical accounts of the flood /landslide susceptibility in the municipality/city. Hence, the MGB constantly recommends strict and continuous monitoring of the barangays, continuing information and education campaigns on disaster preparedness, disaster risk management and mitigations; and strengthening of the Barangay Disaster Coordinating Council.

Attached herewith are the matrices of the municipalities included in the assessment.

MGB-RIII Assessment Team

Carolyn V. Sacdalan Rick Rodell Luis Senior Science Research Specialist Senior Geologist

Clarissa G. Villanueva Senior Geologist Noted by: Noel B. Lacadin OIC, Geology Division

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