ASSESSMENT OF WATER QUALITY OF A RIVER USING AN INDEXING APPROACH DURING THE LOW-FLOW SEASON

The River Chenab is one of the largest rivers in Pakistan with an average annual flow of 5.29 billion cubic metres (BCM). The river traverses a total length of 576 km through a number of densely populated and industrial cities in the Punjab province of Pakistan. In the present study, a segment of 292 km was monitored for a variety of cardinal water quality constituents during the low-flow months of 2006-07 and 2007-08. Water quality indices (WQIs) were calculated for three uses of the river water, i.e. irrigation, drinking and aquatic life, using the CWQI 1.0 model developed by the task group of the Canadian Council of Ministers of the Environment (CCME). The results revealed that the lower river reach (185-233 km) was more polluted than the upper 185 km segment. In this river reach, overall WQI ranking was poor for drinking and marginal for both irrigation and aquatic life. The WQIs for all three uses were ranked poor at the sampling station located at 233 km along the river. Copyright (C) 2009 John Wiley & Sons, Ltd.