MGB: Observe capacity limits as sinkholes increase in Boracay

ENDLESS SUMMER Since travel and health restrictions during the pandemic have been eased, it has been an endless summer in Boracay as tourists have been flocking to the resort island in Malay, Aklan. These visitors are shown enjoying the island’s clear waters in July. —JACK JARILLA

ILOILO CITY—Sinkholes have been documented in the three villages comprising Boracay Island since 2018 but a government geologist said the latest geological survey showed that its number had increased, endangering the stability of structures in the world famous tourist destination in Aklan province.

Engineer Mae Magarzo, chief geologist of the Mines and Geosciences Bureau (MGB) in Western Visayas, said their records showed that the number of sinkholes on the island went up from 798 in 2018 to 801 in 2019, 814 in 2020 and 815 between 2021 and 2022, in the villages of Balabag, Manoc-manoc and Yapak.

Magarzo said the island’s current physical carrying capacity should be strictly implemented as she warned that the increasing number of infrastructures being built on the island would create more sinkholes.

She said unlike the occurrence of landslides that may be determined by observing cracks or lowering elevation, ground collapse due to sinkholes can be harder to anticipate.“[With] sinkholes, when the support underneath is affected, it will immediately fall down, including the structures standing there,” she said.

“We can see that there are more holes. The danger there is that if the island is overcapacitated in structures, there will come a time when many [of these] structures will collapse,” Magarzo added.

The conduct of the geohazard and hydrogeological mapping in Boracay was part of the MGB’s tasks under the national government’s rehabilitation of the resort island since 2018.

According to the Department of Environment and Natural Resources’ (DENR) “subsidence susceptibility map,” the island in Malay town is highly susceptible to subsidence or ground sinking as it also sits on a fault line.

Boracay, according to Magarzo, is made of limestone and is vulnerable to sinkholes.

“The behavior of our limestone is that it melts, so when it gets hit by water, especially if its composition is acidic, [the limestone] gradually melts,” she said.

Structures

Boracay’s carrying capacity assessment in 2018 indicated structures built on the island had exceeded the ideal number.There are 10,250 houses on the island or 4,712 units more than the 5,538 real carrying capacity (RCC) for residential structures.

The island also has 2,779 business establishments, 878 units more than the 1,901 RCC for business.

Boracay has 430 accommodation establishments which is below the RCC for smaller-lot areas at 808 units. It has, however, 154 units that exceeded the RCC for larger-lot areas, set at 276 units.

The RCC was based on the Comprehensive Land Use Program map of the island from 2013 to 2022.

Boracay has a tourist carrying capacity of 19,215 or a daily capacity of 6,405, according to the DENR. The agency’s data indicated that at least 6,085 tourists are arriving on the island per day, well within this carrying capacity.

In Manila, Tourism Secretary Christina Frasco said her department was coordinating with the DENR to look into the matter and ensure the safety of tourists.

RELATED STORIES

Mines bureau maps sinkholes, says they are greater hazards

Boracay is back with vengeance!

—WITH A REPORT FROM JACOB LAZARO