Application of Water Quality Index (WQI) for Quality Zoning, Case Study: Karaj River, Iran

With the increase of living population it has been put under tremendous pressure due to human and other biological activities. WQI is a useful tool for the quick assessmentof any water system. Such WQI will give idea about increase or decrease in pollution rate for the water body under consideration. Monthly, seasonal or yearly changes inthe water quality can be quickly assessed with help of such Index. This index reflects a composite influence of contributing factors on the quality of water for any watersystem. In this research, the physical, chemical and biological haracteristics of KarajRiver near the Tehran city, has been studied to evaluate the suitability of its water for domestic uses. Samples of water were collected from various localities before, in andafter Karaj Dam Lake and were analyzed based on needs for WQI calculation. In this study, WQI were calculated for the best and the least condition for quality zoningdetermination of Karaj water quality. The results conclude that the water quality ofKaraj River, various in direction of river especially before and after dam and was of medium to good quality and can be used for domestic use after suitable treatment.This study is helpful to environmental planning and pollution control measures applicable to the area.

کلیدواژه ها:

WQI ، Karaj River ، Quality zoning ، Tehran