25 percent of water ‘gone’-A A +A
Sunday, March 16, 2014
IF GROUNDWATER extraction continues unregulated, about 25 percent of Metropolitan Cebu Water District’s (MCWD) well fields in Talamban, Cebu City and Mandaue City will yield saline water in 2025.
MCWD assistant general manager for operations Ernie Delco said 25 percent of the projected supply of 200,000 cubic meters (cu.m.) is about 50,000 cu.m. That’s the volume of freshwater that is lost to MCWD consumers every day.
The figure represents the worst case scenario of Metro Cebu’s water supply up to 2025, based on a Japan International Cooperation Agency (Jica) study presented last Thursday by MCWD. In the situation, extraction of groundwater by MCWD and private wells continue unregulated.
The second scenario involves the possibility of regulating MCWD extraction and leaving extraction by private wells unchecked. The third scenario considers the possibility of regulating MCWD and private well extraction.
In the other two scenarios, saltwater intrusion into the aquifer will still occur, although not of the same extent as the first scenario.
The study uses the allowable level of chloride of 250 parts per million in drinking water as set by the World Health Organization, said Ronnel Magalso, MCWD groundwater division manager.
Magalso said the study stresses the need to regulate groundwater extraction.
MCWD Board Chairman Rene Mercado said at the closing of a groundwater workshop last Friday that the “critical state” of Metro Cebu’s aquifers made the water district decide to stop drilling additional wells.
To cope with the growing demand for water, MCWD bought water from private suppliers who tap groundwater outside of critical aquifers, as in the case of Abejo Builders which get water from Minglanilla.
Mercado said MCWD’s future supply will come from surface water sources in Carmen, Danao City and the proposed weir in mountain barangay of Bonbon, Cebu City, which is projected to produce 35,000 cubic meters a day.
Magalso said MCWD only accounts for 46 percent of existing groundwater wells in Metro Cebu. The rest are private wells.
A recent inventory conducted by MCWD and the National Water Resources Board in cooperation with the Lapu-Lapu City Government revealed that there are almost 16,000 private wells, mostly by domestic users, on Mactan Island.
The initial results of an inventory in Mandaue yielded 1,200 private wells so far.
The Water Resource Center of the University of San Carlos found about 19,000 wells in Metro Cebu in the 1990s.
Lasaro Salvacion, MCWD Water Resources Knowledge Center manager, said groundwater sources should be replenished.
The Maghaway Valley in central Cebu has been identified as a major recharge area for Metro Cebu aquifers. But Salvacion said the amount of rainfall that actually seeps into the groundwater table cannot equal the extraction rate.
Salvacion said that because of Cebu’s topography and the denuded state of the watersheds that feeds central Cebu’s rivers, most of the rain that falls on recharge areas end up in the sea as runoff.
To address the issue, MCWD sponsored a workshop as an initial step toward the development of an integrated water resource management plan, which seeks to involve all stakeholders—government and the private sector—in protecting and managing central Cebu’s river basins.
The output of workshop participants will be presented to the Regional Development Council 7’s infrastructure committee, said Delco.
Published in the Sun.Star Cebu newspaper on March 16, 2014.