Water Quality Assessment for the Rivers Karoon, Dez and Karkheh, South West of Iran

Rivers are regarded as the sources of water for various uses including agriculture, industry and drinking. Monitoring quality of these resources due to the recent drought and urban and rural developments is one of the important tasks in the field of environmental management. In this study, we undertook seasonal sampling in nine stations in the rivers Karoon, Karkheh, Dez over a period of one year starting from April 2011. We measured temperature, conductivity, dissolved oxygen, pH, turbidity, BOD, COD and etc. Data were analyzed using Piper and Schoeller diagrams and National Water Quality Index (NSFWQI). Based on the Piper diagram, all three rivers were low in sodium (potassium) - chloride. Also, analysis of parameters measured for NSFWQI showed that all the three rivers in the low rainfall season have an index of less than 50, indicating a poor water quality. In the high rainfall period, the index was more than 50, indicating a medium water quality. However, monitoring of physical, chemical and biological parameters as well as the national water quality index clearly showed the environmental impact of pollution sources entering the rivers.