Water quality assesment based on the Water Quality Index (WQI) approach using geospatial analysis

Abstract

Water quality refers to the chemical, physical, or biological characteristics of water, in which assessing the condition of water relative to the requirements of biotic species or to any human purposes. The aim of this study was to analyze the water quality of the Way Kuripan River based on the Water Quality Index (WQI) calculation method. Water samples were taken from five different areas (WK01, WK02, WK03, WK04 and WK05). WQI was calculated on the basis of six parameters; dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), pH, total suspended solid (TSS) and ammoniacnitrogen (NH3-N). The calculation started by identifying the equation of the Sub-Index (SI) based on the parameter value, calculating the Sub-Index (SI) of each parameter, and calculating the Water Quality Index. The results show that WK01 and WK04 have WQI values of 70.3 and 70.11. Those values show that water quality of the Way Kuripan River was in class III or slightly polluted. WK02 (WQI = 55.8) and WK03 (WQI=53.8) were highly polluted. The lowest WQI of the Way Kuripan River was in WK05 = 38.3, and classified as Class V (highly polluted). Moreover, Geospatial analysis was done to identify the distribution of water quality geographically. It shows that home industry and human activities, were spread along the river flow, and it caused the fluctuation of water quality. The results of this study can be used as a reference by the local government for water resources management.