Quantifying the Costs and Benefits of Coastal Water Quality Improvements in the Ko Chang Marine National Park, Thailand

Sunida Piriyapada, Erda Wang

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


The water quality in Ko Chang Marine National Park coast has been problematic for many years. Recently, a conservation plan has been made by the local government for protecting the ocean beaches by constructing a sewage treatment plant in the region. This study uses the contingent valuation method (CVM) to measure the benefits associated with the proposal of the wastewater treatment plant (WWTP), followed by conducting cost-benefit analysis (CBA) in order to justify the feasibility of the public fund appropriation by the government fiscal policy, such as taxes. A completed questionnaire survey of 300 randomly clustered households was analyzed. Household willingness to pay (WTP) was estimated using Tobit models. The results indicate that the mean WTP for the proposed wastewater treatment project is $73.36 per household per year, translating into an aggregate monetary benefit of $298,774 per year for the local community. Additionally, the CBA result shows that the net present value (NPV) of the project attains $465,162.48 per year, internal rate of return (IRR) reaches 9.14 %, and benefit-cost ratio (B/C) ends up with 2.21 with all those intangible benefits excluded from the calculation. Therefore, the proposed wastewater treatment plant project is economically profitable.

Original languageEnglish
Pages (from-to)149-169
Number of pages21
JournalEnvironmental Processes
Issue number2
Publication statusPublished - Jun 1 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Water Science and Technology
  • Pollution
  • Management, Monitoring, Policy and Law
  • Health, Toxicology and Mutagenesis


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