MGB-7: Incessant groundwater extraction to worsen flooding

CEBU, Philippines - The Mines and Geosciences Bureau-7 has warned the public of the possible effects of incessant groundwater extraction to the environment and mankind.

Ma. Elena Lupo, senior geologist of MGB-7, said that continuous extraction of groundwater would lead to land subsidence to worsening flooding problems in Metro Cebu and other areas if unabated.

 She pointed out that it would greatly contribute to massive and longer flooding and bigger inundation depth of floods.

Despite hundreds of wells in Metro Cebu, the land mass fortunately is still stable, Lupo said.

“But, this is likely to happen if we will not control or stop groundwater extraction,” she said. 

 Groundwater extraction in metropolis is one of major problems due to inadequate regulation. She explained that most of the areas possible for subsidence are those with alluvial deposits, especially in coastal areas.

Alluvial deposits are materials deposited and eroded by rivers upstream, consisting of silt, sand, clay and gravel, as well as much organic matter.

 She said Manila Bay’s land mass, for instance, is lowering down by 2.5 centimeter due to an “excessive” groundwater usage.

She said most rigorous solution and the best one is to stop pumping groundwater for drinking water and use surface waters or rainwaters instead. On top of this, proper water conservation is also encouraged.

Another mitigating factor, according to Engineer Edilberto Paradela, regional director of the Department of Science and Technology-7, is installation of integrated stormwater management system, which serves as water rainfall basins or catchment.

The system is using a technology to reduce pollution from stormwater runoff, limit the disruption to the natural site hydrology by reducing impervious cover, increase infiltration, and allow for the reuse of water to reduce potable water demand and costs.

He said this would not only address the flooding issue but also the need of potable water. He cited that in their facility at DOST, they were able to contain at least 140 tons of rainfall through the technology. Apart from that, they also saved thousands of pesos.

“Our billing is now only pegged around P6,000 a month because of the technology, saving half of the total expenses for  our water consumption. This is a very helpful system and we don’t need to extract waters from our aquifers,” he said.

He added that the system could also help address the prolonged drought.

On the other hand, Raphael Reyes, information officer of DOST-Project Noah, shared the importance of Project Noah to the public especially in disaster risk reduction and mitigation, weather, hazards and advisories, among others.

He said that with more advanced science–based tools, like flood modeling and simulation and storm surge mapping, Philippine Atmospheric Geophysical and Astronomical Services Administration services will be upgraded a notch higher, making it a world-class weather information provider at par with other international organizations.

According to Ramon Aboitiz Foundation Inc, which initiated the forum on preparation and mitigation of effects of water-related disasters,  these measures are needed since an integrated drainage master plan is still in the works and still to be implemented.

“Investing in the right technology and innovations to solve this perennial problem is imperative,” RAFI said in a statement.  (FREEMAN)