Groundwater Quality Index for Water Supply Production

• Main Authors: Warangkana Sungsitthisawad, Somsak Pitaksanurat
• Format: Article
• Language: English
• Published: Thai Society of Higher Eduction Institutes on Environment 2013-07-01
• Series: EnvironmentAsia
• Subjects: groundwater quality index (GWQI); groundwater quality; water supply; Delphi technique
• Online Access: http://www.tshe.org/ea/pdf/vol6%20no2-3.pdf

Groundwater quality index for water supply production, GWQI, was employed as a simple mathematical tool to integrate the complex groundwater quality data into a numerical score. It would guide to select an appropriate water supply treatment process. It was thus necessary to develop such GWQI, which was the main objective of this study. We started searching for significant indicators by requesting 35 Thai experts to consider the importance of 32 water quality parameters through questionnaire based on the Delphi technique. These parameters were aggregated into 10 key parameters, reflecting the appropriate groundwater quality through the process of weighing factors. The most appropriate parameters were estimated from ten such parameters. By reduction of the ten parameters one by one, it was found that the GWQI(6i) was in high agreement with GWQI(10i) (Kappa coefficient = 0.765: 95%CI 0.700 to 0.828). The GWQI (6i) scores were confirmed by Ramesh´s tool with a high correlation (r = 0.768, 95% CI = 0.529 to 0.894, p-value = 0.001). Therefore, the GWQI(6i) could be used as the appropriate tool for groundwater quality assessment. Implementation of GWQI(6i) would save budget and time for analysis, and could provide a rapid water quality determination for the urgent situation.