Photo credits: Michael Magallanes Oral (Personal Assistant of Mayor Silva) via his Facebook Account

By: Ollyn Rey T. Balignot, Senior Geologist

A Low-Pressure Area (LPA) observed on March 31, 2021 that brought scattered rains throughout Zamboanga Peninsula had reportedly caused the overflowing of Sibuguey River affecting the Municipality of Imelda the most.  The heavy rainfall was also felt by the neighboring Municipalities of Imelda, Zamboanga Sibugay, specifically the Municipalities of Diplahan, Zamboanga Sibugay and Bayog, Zamboanga del Sur, where the headwaters of the Sibuguey River emanate, caused the river to overflow affecting low-lying areas of the Municipality of Imelda, particularly along the floodplains of Barangays Balugo, Gandiangan, La Victoria, Lumpanac, Lumbog, San Jose, and Sta. Barbara.

Through the phone-patch interview with Mr. Michael Magallanes Oral and Ms. Mercy Delos Santos of LGU-Imelda, MGB-IX Geologists Ollyn Rey Balignot, Merill Jan Balignot and Abbygail Soco gathered the information that the flooding started at approximately 10:00 AM on April 1, 2021 which lasted for about twenty-eight hours (28 hrs) and subsided at around 12NN of April 2, 2021. This incident was however, not a surprise because based on the Geohazard Matrix issued last October 2011 during the conduct of 1:10,000 scale Geohazard Assessment, the said barangays were categorized within Moderate to High Flood Susceptibility.

During the incident, the Mines and Geosciences Bureau Regional Office IX (MGB, RO-IX) Geohazard Operation Center (Geo OpCen) was constantly monitoring the situation via social media, coordination with the MDRRMO of LGU-Imelda and had issued a Situational Report to the MGB, Central Office last April 1. The reported flooding incident that affected people, infrastructures, and roads were evaluated and were given appropriate short and long-term recommendations as follows:

  • Observe proper legal easement along active bodies of water specifically along the floodplains of Sibuguey River, and if possible, relocate existing houses that are vulnerable and much likely to be affected by such hazards;
  • Develop an early warning system such as installation of Flood Hazard Warning Signage on critical areas and installation or improvement of engineering mitigating measures for flood along Sibuguey River;
  • Utilization and integration of the 1:10,000 scale Geohazard Map in the future land development within the municipality especially along the floodplains of Sibuguey River;
  • Constant communication and provide updates to barangay officials and the Imelda Municipal Disaster Risk Reduction and Management Office (MDRRMO) on geohazard situations in the aforesaid barangays;
  • The Local Government Unit of Imelda especially of the affected barangays through its respective Barangay Disaster Risk Reduction and Management Council (BDRRMC) should come up with or enhance its respective Disaster Preparedness and Contingency Plan/Disaster Risk Reduction and Management Plan for the floodplains of Sibuguey River; and
  • Observe the rapid increase/decrease of Sibuguey River’s water level, possibly accompanied by increased turbidity (soil content) and drainage and channel maintenance such as clearing of channel debris/clogged drainages are further encouraged.