Ecological Water Quality Index Development and Evaluation of Water Quality of the Satluj River

摘要

In this study, the use specific water quality index for ecological use (WQI_E) has been developed. The selected parameters grouped into 3 sub-indices categories: General parameters (SI_(gp)), heavy metals (SI_(hm)) and pesticides and other toxic organic compounds (SI_(ptoc)). Relative importance assigned to the general parameters through expert opinion analysis by Pairwise comparison technique and sub-index (SI_(gp)) was calculated through aggregated weighted root sum function. Transformation curves were established for each of the parameter to assess the variation in water quality levels, which were based on the water quality standards and criteria used by several countries. In case of the heavy metals and the pesticides, flexibility of using open ended lists of parameters has been introduced where values of parameters were first transformed into concentration ratios by division with corresponding prescribed water quality standards and maximum operator sub-indices were used. Overall WQI_E has been obtained by geometric mean of all the 3 sub-indices. The river water quality was considered as excellent when the WQI_E was 92-100, as good when 70-92, as moderate when 30-70, as poor when 8-30 and as worst when ＜8. In addition, WQI_E used for analyzing temporal and spatial water quality of the river Satluj.