Southwest Negros loses 9.5 hectares of coastal land annually due to erosion

MANILA, Philippines - The Mines and Geosciences Bureau (MGB) has recommended to the local government of Negros Occidental the implementation of measures that would stop the rapid coastal erosion occurring in the province for the past 58 years.

A report created by the bureau as a result of the coastal geohazard assessment and shoreline mapping done in December 2014 in several cities and municipalities in the province showed that the southern coast had been losing 9.5 hectares of land a year to coastal erosion.

Surveyed were the shorelines in Bago City and in the municipalities of Pulupandan, Valladolid, San Enrique, Pontevedra, Hinigaran, and Binalbagan.

“Analysis of coastlines between 1956 and 2014 in southern Negros Occidental suggested that the corridors eroded away by waves and currents summed up to 550 hectares,” said the MGB.

The widths of eroded corridors within the study area range approximately from 9 to 334 meters with a median value of 144 meters, the widest being in Barangay  Enclaro (334 meters) in the town of Binalbagan.

While some 9.5 hectares are lost annually through coastal erosion in the areas placed under study, some 3.9 hectares are added to coastlines through sediment accretion.

The MGB, nonetheless, considers the rate of coastal erosion in southern Negros Occidental to be high.

As such, the bureau said concerned local government units have launched measures to stop coastal erosion through a mix of bioengineering and setting up hard structures.

The MGB recommends the planting of mangroves and other plant species that can adapt to coastal environment at the upper bench slope of accreted zones.

The MGB also advised that land titles should not be issued for occupancy rights on the emergent or accreted lands to reduce the risk of coastal hazards.

Severe erosion causes coastal flooding with the occurrence of storm surges and tsunami waves. These conditions may be aggravated by high tide and ground subsidence (sinking). In Negros Occidental, potential tsunami generators are the Negros Trench and the Sulu Trench.

The report said the areas surveyed have been rated to have high susceptibility to coastal flooding, especially those facing the open sea, and have no wide and dense mangrove forests that act as buffers.

Negros Occidental produces half of the country’s sugar output.