Philippine officials are calling for massive dredging operations to remove 4.7 billion cubic meters of volcanic lahar deposits that threaten to flood three towns in Zambales province, warning that failure to act could submerge entire communities.
The Mines and Geosciences Bureau (MGB) said the deposits, remnants from Mount Pinatubo’s catastrophic 1991 eruption, continue to clog river systems and pose severe flooding risks to San Felipe, San Narciso and Botolan towns more than three decades after the volcanic disaster.
MGB Regional Director Noel Lacadin told resort owners and provincial officials during a meeting on Monday that dredging operations are urgently needed to prevent catastrophic overflow.
The warning comes as the Philippines faces increasingly severe weather patterns that could trigger devastating floods if the lahar-clogged waterways overflow during heavy rainfall periods.
Of the 6.7 billion cubic meters of lahar spewed by Pinatubo during one of the 20th century’s most destructive volcanic eruptions, about 4.7 billion cubic meters were deposited in Zambales rivers.
The Bucao River absorbed the largest share at 3 billion cubic meters, representing 63.8% of the total, while the Sto. Tomas River received 1.6 billion cubic meters or 34% of deposits.
Dredging and hauling lahar sand from the Bucao, Maloma, Sto. Tomas and Pamatawan rivers is critical to prevent further overflow and flooding, Lacadin said.
The meeting represented a collaborative effort between the provincial government and tourism stakeholders to address the mounting crisis. Governor Hermogenes Ebdane Jr. led the dialogue with resort owners from the popular surfing destination of Liwliwa.
“With open discussions and cooperation, we came up with a singular goal to push for a more structured development of the area and the well-being of the community and the town of San Felipe,” Ebdane said.
“This collaboration between the provincial government and stakeholders is proof that problems can be resolved with an open line of communication.”
Ebdane stressed the urgency of dredging operations, explaining that lahar deposits fundamentally alter natural drainage patterns.
“Dredging is essential because lahar deposits block rainwater from flowing directly to the sea, forcing water into rice fields and residential areas, which worsens flooding,” the governor said.
However, the scale of the required dredging operation is staggering. Only 50 million cubic meters have been dredged and hauled from the river systems so far, representing just over 1% of the total volume threatening the region. This leaves more than 4.6 billion cubic meters still blocking critical waterways.
The massive undertaking underscores the long-term challenge facing authorities in preventing catastrophic flooding in the densely populated coastal province, where tourism and agriculture form the economic backbone of local communities.
Mount Pinatubo’s 1991 eruption displaced hundreds of thousands of people and caused billions of dollars in damage, with lahar flows continuing to plague the region for years after the initial eruption as monsoon rains mobilized volcanic debris.
Business News Asia
