An assessment of saltwater intrusion in Cebu City aquifers

• Main Authors: Guerra, Nicole H., Mercado, Nicole Bernise O., Ng, Raymond Albert L., Ventura, Nelson Stephen L.
• Format: text
• Language: English
• Published: Animo Repository 2016
• Subjects: Groundwater > Philippines > Cebu City; Saltwater encroachment > Philippines > Cebu City; Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/7887
• Institution: De La Salle University

Constructing adequate models of the groundwater aquifer is an essential component of integrated water resources management, especially in the effort to curb the effects of saltwater intrusion in coastal areas. In the Philippines, Cebu City has been declared as among the major cities with the most critical balance conditions (DENR-CEST 2004), suffering from the depletion of groundwater sources and the incidence of saltwater intrusion. However, save for the ongoing well-monitoring and plotting of isohaline contours by the Metro Cebu Water District (MCWD), following the publication of DENR-CEST (2004) not much attention had been given to possibly construct a groundwater model of Cebu City with updated data. In this light, an analytical model is useful for a quick assessment of the groundwater condition given limited access to data (Rushton, 2003) The paper presents a simplified analytical model of the Cebu City aquifers to determine the current position of the presumed sharp saltwater-freshwater interface, as well as visualize the cross-sectional profiles of wells at drawdown and upcoming. Ten representative wells were assessed individually regarding the likelihood of saline contamination. Moreover, the upcoming of these ten wells has been modelled considering the effects of well interference. In defining the freshwater head and the distance of the toe of the freshwater-saltwater interface from the shore, the Glover relation was primarily used. Aside from the contribution to a greater public awareness of the threat of saltwater intrusion, the findings may serve to guide the policymaking of MCWD with regard to establishing allowable rates of groundwater extraction.