Assessment of Surface Water Quality of Huai Luang River in Udon Thani, Thailand, Using the Water Quality Index

Abstract

This study aimed to analyze the surface water quality of the Huai Luang River using the water quality index (WQI) method. Five parameters were analyzed to assess the water quality of the Huai Luang River; they were dissolved oxygen (DO), biochemical oxygen demand (BOD), total coliform bacteria (TCB), fecal coliform bacteria (FCB), and ammonia (NH3). The Huai Luang River is the municipality’s primary consumption water source in Udon Thani province, Thailand. WQI classifications were calculated by using the surface water quality standards program of Thailand’s Pollution Control Department (PCD-WQI). The results showed that the water quality in the Huai Luang River was bad status, in the WQI range of 54-60 scores. The major sources of pollutants in the Huai Luang River were wastewater from communities, agriculture, and animal farms are the main contributors to water pollution. Seasonal water quality variations were observed at each monitoring site from March 2022 to February 2023. WQI concentration in the rainy season (March to June) was generally among the highest (57 score) compared with other seasons (56 score in winter and 54 score in summer). While the WQI concentration of the upstream sampling site (domestic wastewater) had the lowest (55 score) compared with the other sites (59 score for midstream and 60 score for downstream). Therefore, this research study presented valuable information on WQI for the Huai Luang River for water quality management by administrators and local community participation.