Salinization of aquifers and estimation of its damage and the cost of groundwater protection in Cebu City, Philippines

Date

1999

Abstract

Seawater intrusion, which is caused by over-extraction is a major problem in Cebu City. This study was conducted to estimate the costs associated with seawater intrusion and the protection of the aquifer from further intrusion. A benefit- cost analysis for reduction of extraction using surface water, desalted water, desalted saline groundwater, and metering was conducted. Cost-based approaches including avertive expenditures, cost of illness, and loss of revenue were used in the estimation of damages of salinization. The damage of intrusion on well production capacities (both private and MCWD) and on health (i.e, urinary tract infection and renal failure) was valued. The damage by distance of seawater intrusion was also determined.Estimation showed that the costs of seawater intrusion is about PhP130.6 million which is almost 0.2percent of the 1997 gross provincial product (GPP) for Cebu. About 93percent of this total is due to loss of well production capacities while 7 percent is accounted for the health damage. The costs vary with the distance of seawater intrusion from the coast. The distance category 0-500 m has the highest value of impacts ranging from PhP0.14 million for the loss of drinking water to PhP4.12 million for health damage. The distance category 1500-2000 m got the lowest estimated value of damage.Reducing the groundwater extraction to the safe yield through metering would cost P420.48 million, which is 47 percent lower than the cost to be incurred if surface water were used, 600percent for the desalted seawater alternative, and 300percent if desalted saline groundwater were used. The reduction using desalted seawater has the highest estimated cost of P3.11 billion.The benefit-cost analysis for these strategies indicated positive net present values (NPV's) for metering and shifting to surface water and negative NPV for the others. The results justify the implementation of the proposed surface water development projects in Cebu and the intensification of metering in the area.

Document Type

Master Thesis

Degree

Master of Science in Environmental Science

College

School of Environmental Science and Management (SESAM)

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 995 1999 E8 B34

This document is currently not available here.

Share

COinS