Spatio-temporal analysis of the Karun River water quality

Abstract

The spatio-temporal variations of the water quality of the Karun River using national sanitation foundation water quality index (NSFWQI) are analysed in this paper using time series analysis and geographic information system (GIS). Monthly data including pH, temperature, dissolved oxygen (DO), five-day biochemical oxygen demand (BOD), total solids (TS), PO43–, NO3–, turbidity and fecal coliform are analysed for 2007-2012. Calculated NSFWQI time series during the study period shows that the water quality of the river lies in the medium class. The results of time series analysis show that periodicity and trend are not significant in the majority of stations. The spatial analysis results demonstrate that the water quality in Ahwaz urban area is slightly poorer than in the rest of the river. Overall, the spatio-temporal distribution of the NSFWQI values indicates that changes are negligible and show the balance between the pollutants input and self-purification capacity of the river.