A comparison of water quality indices for Karkheh storage dam

Karkhen storage dam is the largest dam of this kind in iran with a target capacity of 7.2´10 9m3. It is located in North West of Khuzestan province on Karkheh River. This study was aimed at the determination of an appropriate quality index for long term monitoring of the effects of this dam on Karkha River water quality. Four sampling stations were established. Then four standard quality indices, i.e. OWQI, DSWQI, NSFWQIm and NSFWQIa were used to test water quality in a bimonthly basis. The Jil Janwick approach was used to compare data collected by the latter indices. The comparisons suggested that NSFWQIm is a more appropriate index for water quality monitoring of Kerkhen River compared to the rest of the indices