The Mines and Geo Sciences Bureau undertook a geohazard assessment in the province of Lanao del Norte as part of the Nationwide Geohazard Assessment, However, Municipalities of Baroy, Kolambugan and Maigo have the initial reports.
This study concludes that flooding will likely impact the study area. This usually resulted in an abnormally excessive precipitation. The most flood-prone portions in the study area are the low-lying area, coastal area and the floodplains of Rawan River, Ininguian River and the minor tributaries. Parts of Brgy Lower Sagadan, San Juan, Baroy Dacu, Raw-an Pt. and Princesa (Puroks 4, 6 & 7) are flood-prone areas.
Based on the assessment, parts of Brgys. Lindongan and Bato are marked as moderate to high susceptibility for landslides. These areas are blanketed by Late Pliocene-Quaternary Volcanic Deposit especially lava flows. Parts of Brgys. Pendulonan, Andil and Libertad are considered low susceptibility for landslides.
Based on the Liquefaction Susceptibility Map (1996), the study area especially of parts of Brgys. Raw-an Pt., Bagong Dawis, Baroy Dacu, San Juan, Poblacion and Lower Sagadan, is a liquefaction-susceptible area.
Flooding hazard will more likely impact the study area. The flood-prone portions in the study area are the low-lying areas, coastal areas and the floodplains of Kulasihan, Titunod, Kolambugan and Manga Rivers, and Simbuco Creek and their tributaries.
Based on geomorphology and interviews, Brgys. Simbuco, Manga, Tabigue, Mukas (Purok 1), Caromatan, Titunod, Baybay, Poblacion, Austin Heights, Riverside, Rebucon, Muntay and Kulasihan are considered flood-prone areas.
Based on the study, parts of Brgys. Baybay, Mukas, Titunod, Sto. Nino, Poblacion, Palao, Manga, Tabigue, Caromatan, Austin Heights and Pantar are marked low to moderate susceptibility for landslides.
The study believed that the southwest portion of the area which is basically characterized by hilly and rugged terrain, namely Brgys. Lumbac and Sucodan, are landslide prone areas.
Areas susceptible to liquefactions are those areas blanketed by the alluvial deposits and terrace gravel deposits especially those in the lowlands (i.e., parts of Brgys. Brgys. Simbuco, Manga, Tabigue, Mukas, Caromatan, Titunod, Libertad, Baybay, Poblacion, Austin Heights, Riverside, Rebucon, Muntay and Kulasihan).
The most prominent geohazard that will likely impact on the study area is flooding caused by excessive precipitation. The flood-prone portions in the study area are the low-lying areas, coastal areas and the floodplains of Liangan, Maigo at Kulasihan Rivers and their tributaries. These drainages discharge their loads toward Panguil Bay.
Based on geomorphology and interviews, Brgys. CMR (Puroks 2-5), Liangan West (Puroks 1 & 2), Labuay (Purok 1 & 2), Balagatasa (Puroks 3 & 6), Segapod (Puroks 5 & 6) and Kulasihan, situated within Liangan, Maigo and Kulasihan Rivers are considered flood-prone areas.
Based on the rapid geohazard assessment, parts of Brgys. Kulasihan and Maliwanag are marked with moderate susceptibility for landslides while Brgys. Mahayahay, Camp 1, Sta. Cruz and Mentring are considered low.
Areas susceptible to liquefactions are those areas blanketed by the alluvial deposits especially those in the lowlands (i.e., parts of Brgys. Liangan, CMR< PoblaciÃ³n, Labuay, Balagatasa, Segapod and Kulasihan).
Fortunately, there are mitigating measures that can be done to lessen the effects of the abovementioned natural geohazard. Building shore protection such as breakwaters, jetties, groins bulkheads and seawalls, are good mitigations for areas prone to coastal erosion.
However, proper consultation with technical experts regarding the construction of infrastructure projects along the coasts is advised to have a thorough study of its effects upon the coastal environments and to ensure safe and sound structures with no detrimental effects on the coastal environment. Improper construction and installation may do more harm than good to the coastal ecosystems.
Land use development along the coastal zone should be regulated including establishment of setback codes. Appropriate land use zoning should also be implemented.
More dangerous slopes can be made stable by retaining walls, rip-rap, shotcrete and other proven engineering measures.
The geohazard assessment data, especially those communities residing in the identified flood-prone and landslide-prone areas, should always factor out in all the development projects of the LGU. The LGU should likewise regularly monitor progress of work, from revision of plans to actual development and if possible, extending to eventual utilization.