Summary Report
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SUMMARY REPORT RESULTS OF THE MGB GEOHAZARD ASSESSMENT COVERING THIRTY TWO (32) MUNICIPALITIES/CITIES IN THE PROVINCE OF NUEVA ECIJA 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 Philippines, geologists from the Mines and Geosciences Bureau-Regional Office III (MGB-R3) conducted a geohazard assessment of the barangays in the municipalities/cities in the province of Nueva Ecija. Each barangay 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 Low • Low to gently sloping • No presence of tension cracks 1 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 sitios. 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 ten (10) municipalities/city 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. 2 Table 1. Number of Assessed Barangays Municipality/City Total Barangays Number of Assessed Barangays 1. Aliaga 26 26 2. Bongabon 28 28 3. Cabanatuan City* 89 89 4. Carranglan 17 17 5. Cuyapo 51 51 6. Gabaldon 16 16 7. City of Gapan 23 23 8. Gen. M. Natividad 20 20 9. Gen. Tinio 12 12 10. Guimba 64 64 11. Laur 17 17 12. Licab 11 11 13. Llanera 22 22 14. Lupao 24 24 15. Science City of Muñoz 37 37 16. Nampicuan 21 21 17. Palayan City* 20 20 18. Pantabangan 14 14 19. Peñaranda 10 10 20. Quezon 16 16 21. Rizal 22 22 22. San Jose City 38 38 23. San Leonardo 15 15 24. Sta. Rosa 33 33 25. Sto. Domingo 24 24 26. Talavera 53 53 27. Talugtug 28 28 28. Zaragosa 19 19 29. Cabiao** 23 23 30. Jaen** 27 27 31. San Antonio** 16 16 32. San Isidro** 9 9 TOTAL 845 845 *- UNDP 2005 (MGBCO), updating of hazard maps conducted by the MGBR3 **- conducted during the 2004-2005 hazard mapping along Pampanga River 3 SUMMARY OF THE ASSESSMENT: 1. Municipality of Aliaga • In terms of landslide susceptibility, no barangays in Aliaga have the potential for landslide occurrence. • Active riverbank erosion is observed in three (3) barangays (Sta. Monica, San Eustacio and San Emiliano). • There are ten (10) barangays with none to low susceptibility to flooding (Magsaysay, Santiago, San Felipe (Bata), Umangan, San Eustacio, Sto. Tomas, Macabucod, San Pablo (Matanda), Poblacion Centro and Poblacion West) • There are ten (10) barangays with low to moderate susceptibility to flooding. Most of the residential area has low flooding susceptibility. Agricultural areas of the barangay has moderate to high susceptibility (Sto. Rosario, Bucot, San Pablo Bata, Poblacion East I, Poblacion East II, Poblacion West III, San Carlos, Betes, Pantok and Sunson). • There are three (3) barangays with moderate to high susceptibility to flooding. These barangays have portions adjacent to active creeks and river channel (Sta. Monica, San Juan and San Felipe Matanda). • There are two (2) barangays with low, moderate to high susceptibility to flooding. The barangay has naturally low-lying areas and portions located near active creeks and river channel (San Emiliano and La Purisima). 2. Municipality of Bongabon • There is one (1) barangay with high landslide and debris flow susceptibility (Labi) • There are four (4) barangays with low flood susceptibility (Magtanggol Palomaria, Sinipit and Olivete). • There are two (2) barangays with low to moderatye flood susceptibility (Antipolo and Makabaklay) • There are five (5) barangays with moderate flood susceptibility (Pesa, Tugatog, Larcon, Cruz and Santor). • There are three (3) barangays with moderate to high flood susceptibility (Vega, Ariendo and Lusok). 4 • There are four (4) barangays with portions susceptible to high level floods. These barangays are located near active creeks and Digmala River and with portions that are located in generally low-lying areas. (Labi, Curva and Caingin). • Riverbank erosion is identified in four (4) barangays (Calaanan, Pesa,Tugatog and Larcon) 3. Cabanatuan City • Updating of the 2005 Hazard Maps (UNDP 2005) • Location of the barangay centers included in the geohazard data base • Hazard identified is mostly related to flooding from the overflow of major rivers including Pampanga River, Cabu River and creeks traversing the area. • Majority of the city has a low susceptibility to flooding. Barangays with moderate to high susceptibility are those located adjacent to the river and located in the generally low-lying areas. With historical moderate to high susceptibility to flooding and flashflooding particularly in the areas influenced by Pampanga River and Cabu River, and flash flood coming from the adjacent mountainous municipalities and with natural drainage draining towards the city. 4. Municipality of Carranglan • There are two (2) barangays with low landslide susceptibility (Salazar and Burgos) • There are six (6) barangays with moderate to high landslide susceptibility (Gen. Luna, Capintalan, Minuli, Putlan, Piut and Joson(Digdig) ) • Active riverbank erosion is observed in two (2) barangays (Piut and Puncan) • There are four (4) barangays with low susceptibility to flooding (T. L. Padilla, F. C Otic, Bunga and Putlan) • There are six (6) barangays with low to moderate susceptibility to flooding. Most areas of the barangay are low susceptible. Agricultural lands and portions near creek/river are moderately susceptible to flooding. (D. L. Maglanoc, G. S. Rosario, R. A. Padilla, San Agustin, Puncan and Bantug) • There are two (2) barangays with portions susceptible to high level floods. These barangays are located near active creeks and Carranglan River and with portions that are located in generally low-lying areas. (Bantug and Gen. Luna) 5 • There are six (6) barangays with landslide susceptibility due to faulting and seismicity (Capintalan, Minuli, Putlan, Piut, Joson (Digdig) and Puncan) 5. Municipality of Cuyapo • There are thirty five (35) barangays with low susceptibility to flooding (barangay centers and populated areas) in the municipality of Gerona (Sta. Clara, Nagmisaan, Burgos, Cabileo, Curva, Simimbaan, Sabit, Bued, Malineng, Sta. Cruz, Cacapasan, Colosboa, Rizal, Salagusog, Columbitin, Paitan Sur, Paitan Norte, Nagcuralan, San Juan, Landig, Bonifacio, Baloy, Tutuloy, Calancuasan Sur, Calancuasan Norte, Luna, Maycaban, Landig, Cabatuan, Malbeg, Bantog, Latap, Pugo, District 1,2 and 6). Most of the purok affected with localized flooding are located in the low-lying portion of the barangay, do not have sufficient drainage and located near the creek/river systems traversing the barangay. • The are sixteen (16) barangays experiencing different susceptibility to flooding from low, moderate to high depending on the topographic location (Tagtagumbao, Ungab, Districts [4, 5, 7, 8], San Antonio, Loob, Bentigan, San Jose, Bulala, Bibiclat, Matindeg, Bambanaba, Piglisan, Villa Flores). These are low-lying areas affected by the overflow from the creek/rivers and excessive surface run-off coming from the adjacent barangays and municipalities. Backflooding results from the inadequate drainage and exit points during unusually heavy rainy day and typhoon periods. Structurally controlled flooding such as elevated roads and road system with insufficient drainage, irrigation canals and excessive release of water from dams in the nearby municipalities of Nueva Ecija and Pangasinan is also a possible cause. • The agricultural areas/farm lots have a moderate to high susceptibility to flooding. • Localized flooding that usually subside after the rains can be attributed to inadequate drainage system during periods of unusually heavy precipitation. • For landslide susceptibility, there are five barangays with low to moderate susceptibility to landslides. The topography is generally gently sloping and no tension cracks were observed (Paitan Sur, Paitan Norte, Nagcuralan, San Juan and Landig). 6. Municipality of Gabaldon • There are three (3) barangays with high landslide susceptibility (Cuyapa, Pinamalisan, and Sawmill).