GIS backed parametric surface and groundwater quality indexing in the vicinity of a multi-utility system tank

Abstract

Parametric water quality indexing (WQI) helps integrate the interwoven effects of independent parameters which may enhance or impair the desirable physico-chemical and biological characteristics of both surface waters and groundwater reserves. Monsoon and post-monsoon status of the distribution of such parameters will give an insight on improvising the qualities of water for multiple usages in the vicinity of a tank and its influential area on groundwater contamination. A typical system tank in Coimbatore urban reach of the Noyyal river was studied by using GIS applications. The test values of all parameters considered were subjected to indexing for water quality grades inflicted by the presence of contaminants. On a 1 to 5 gradation, the study area was found to have a weighted mean water quality index of 2.34 and 2.35 for tank surface water during the monsoon and post-monsoon periods, respectively. In case of ground water sampling, the same was found to be 2.17 and 2.19 for the respective situations. The overall hazard rating was characterized under medium to high, warranting quarantine measures to safeguard the water quality standards for multiple uses in the study locality, pinning the eyes on dissolved oxygen improvements, turbidity control mechanisms, alkalinity amendments and moderations of hardness prevailing as high hazard indicators. The pre-monsoon season ratings were nearing the critical conditions at overall ratings ranging from 3.03 to 2.65 (high to severe) for surface and groundwater, respectively.