Evaluating Raw and Treated Water Quality of Tigris River within Baghdad by Index Analysis

A water quality index (WQI) is a single value indicator of the water quality determined through sum-marizing multiple parameters of water test results into simple terms for management and decission makers. In this paper, thirteen parameters were considered. On the basis of these data, raw and treated drinking water from Tigris River within Baghdad were analyzed. Cluster analysis conducted on the WQI data in this area was applied to detect the fluctuation of water quality. In this study, WQI showed that Tigris water never reached “Excellent” levels nor fallen to “Unsuitable” condition, except in occasional untreated water samples. Effects of various sources of pollution were evident and the needs for intensive studies on WQI became evident.