Development of simplified WQIs for assessment of spatial and temporal variations of surface water quality in upper Damodar river basin, eastern India

In this study, four surface water quality datasets of upper Damodar river basin (DRB) covering three seasons; pre-monsoon, monsoon, post-monsoon and annual, for years 2007-2010 were generated by analyzing 280 grab water samples. Each dataset consist of water quality constituents of 35 monitoring stations and sample of each station was evaluated by 17 critical parameters (total 4760 observations). Furthermore, each dataset was treated using six water quality indices (WQIs): four developed simplified indices (WQI(m), WQI(min), WQI(DO), and WQI(pca)) and two existing extended indices (WQI(obj) and WQI(sub)), to assess spatiotemporal variations and suitability for human use and aquatic life. Results revealed that developed indices show on an average similar spatiotemporal variations as compared to WQI(obj) at a lower analytical cost at most of sampling sites comes under good to medium categories of water quality. Geographical information system (GIS) technique was also used for generation of temporal pollution potential maps of DRB. Consequently, this study also presents the necessity and usefulness of developed indices over extended indices especially for the developing countries, because the cost of monitoring and expenses associated with the implementation is less compared to extended methods and generated maps may also facilitate the decision-making processes under various scenarios considering spatial and temporal variability in DRB.