By Catherine J. Teves
MANILA, July 23 — An expert is recommending the institutionalization of a nationwide system for monitoring withdrawal of the country's already over-extracted groundwater.
Dr. Vicente Tuddao Jr., River Basin Control Office (RBCO) executive director, raised urgency for such system, warning more excessive withdrawal of this natural resource will further lower the water level and lead to land subsidence and salt water intrusion which compromises availability of water for domestic and agricultural use.
"We must effectively regulate withdrawal of groundwater," he said.
Tuddao hopes the government can implement as soon as possible RBCO's proposed groundwater management and development plan which also highlights the need for effective monitoring.
RBCO prepared such a plan, reporting about 50 percent of people nationwide tap groundwater for use as drinking water.
Groundwater is also used by agriculture (32 percent), industry (15 percent) and other sectors (4 percent).
National Water Resources Board (NWRB) data since 2002 show about 60 percent of groundwater extraction in the country is without water right permits, RBCO reported.
"We have some 140 billion cubic meters of surface water – that resource is adequate to meet our needs and must be prioritized for use instead of groundwater," Tuddao said.
He noted the country has 20 billion cubic meters of groundwater – a fraction of available surface water.
RBCO is recommending a review of previous and present government initiatives on groundwater monitoring.
Such review aims to help authorities concerned develop the most effective system possible for tracking withdrawal of groundwater, RBCO noted.
Several areas are already reeling from negative impacts of excessive groundwater extraction.
Earlier studies show the most water level decline — between 80 and 100 meters – was experienced in the Pasig City-Taytay area of Metro Manila, RBCO said.
Another growing problem in the country is land subsidence which refers to sinking of land over time due to excessive pumping of groundwater, experts reported.
Salt water intrusion, from movement of sea water towards land, is a third problem in areas where groundwater is over-extracted.
"Damage from saltwater intrusion is practically irreversible as seawater and freshwater mix," Tuddao noted.
Authorities already identified eight over-extracted locations within and near Metro Manila.
The locations are Bulacan province's Guiguinto municipality and Bocaue-Marilao area, Meycauayan-North Caloocan area, Navotas City-Caloocan City-West Quezon City area, Makati City-Mandaluyong City-Pasig City-Pateros area, Paranaque City-Pasay City area, Las Pinas City-Muntinlupa City area and Cavite province's Dasmarinas area.
"Electrical conductivity, which gives an indication of salinity, shows that the coastal strip of Metro Manila affected by seawater intrusion ranges from two to five kilometers from the shoreline," RBCO also noted.
RBCO further reported Metro Cebu's groundwater is already being affected by saline water.
Tuddao said RBCO will meet with NWRB to discuss the proposed groundwater management plan and its implementation.
"We have no concrete monitoring system at present so the plan's implementation will be crucial to conserving our groundwater," he said. (PNA) scs/CJT/mec