BY ROGER M. BALANZA
A visiting United Nations expert on water resource management has warned of seawater intrusion into the city aquifer if the local government allows uncontrolled use of its groundwater reserve.
When that happens, it would be irreversible, said Dr. Shahbaz Khan, Chief of Section on Sustainable Water Resources Development and Management of the United Nation Educational, Scientific and Cultural Organization (UNESCO).
Khan’s warning comes as the Davao City local government is locked at the crossroad of whether or not to approve the controversial AboitizPower P25-billion, 300-MW Circulating Fluidized Bed Combustion (CFB) coal-fired power plant.
The plant, to be located atop the city aquifer in Binugao, Toril would need about 1,500 cubic meters of fresh water a day for its cooling system to be pumped out of the city’s groundwater reserve.
The city depends upon the underground reservoir for drinking water and other domestic needs of its 1.4 million inhabitants.
Although already endorsed by the Davao City Council, the project of the Aboitiz-owned company has suffered a snag.
Last week, Vice Mayor Rodrigo Duterte, who heads the local
legislative body, said he would oppose the project following information the plant would siphon off water from the underground water source. He said the groundwater reserve should be protected for the future generations of Dabawenyos.
Duterte had suggested conduct of further study on the potential threat of the coal plant to the water resource or that AboitizPower draw out water for its cooling system from surface water like rivers.
The Davao City Water District (DCWD), the city’s water utility firm which sources out supply from the reservoir located in the Dumoy-Toril area south of the city, said the water reserve has a lifespan of only 50 years if no alternative sources are found. The DCWD is developing a gravity-type surface water development project utilizing an upland river to supply half of the population in the city’s northern district. The project is aimed at easing pressure on the water reservoir already being depleted by several-intensive industries.
Khan is no stranger to Davao City, regularly coming here to assist local stakeholders in planning water resource management strategies through HELP Network Davao, which he help organized five years ago.
Khan bared the scary scenario of seawater intrusion into the underground water reservoir at the sideline of the 3-day Symposium on Water Resource Management and Hydro Hazard held in Davao City last week.
The symposium was organized by the HELP Davao Network headed by Davao City councilor Marissa Salvador-Abella, chair of the city council committee on environment. Kahn is an advisor to HELP Davao Network.
Once seawater seeps in, it would be irreversible, Khan told a group of water conservation stakeholders during a dinner composed of Davao City councilor Arnolfo Ricardo Cabling, former chair of the city council committee on environment and author of the landmark Davao City Watershed Management, Protection and Conservation Ordinance, Abella, council committee on environment chair and members of HELP Network Davao.
Cabling said Khan told his group that over-utilization of the reservoir could deplete volume and force seawater to seep in to contaminate the reserve.
Seawater intrusion is now happening in the water resources of Cebu City and Manila due to over-utilization of their underground water reserves.
Khan, offhand, told the group, the AboitizPower would pose greatest threat if it pumps out water from the groundwater reserve, the plant being located at the aquifer in the coastal area where seawater and fresh water meet.
Seawater is four times denser than fresh water, said Cabling quoting Khan. Which means that, according to Khan, seawater intrusion would be easier if there is depletion in the reservoir, which would need four times the pressure of fresh water for the intrusion to be prevented.
Khan, an Australian of Pakistani descent, also heads the UNESCO Water Education for Sustainable Development and Hydrology for Environment, Life and Policy (HELP), which advises UN member states on environmental and water management policies IN the Asia-Pacific and African regions.
While here Khan witnessed the launch of the Customized IWRM Guidelines for Davao City and Region XI, a comprehensive guide on water resource management developed by the Department of Science and Technology (DOST) and the National Economic Development Authority (NEDA) regional offices in the Davao Region with technical and fincial assistance from UNESCO. ROGER M. BALANZA