Water Quality Assessment and Application of SWAT Model for Hydrologic Simulations in a Mined Watershed

This paper explored the application of Soil and Water Assessment Tool in modelling hydrological processes of opencast mined affected Olidih watershed of Jharia coalfield region in India. The effect of opencast mines on hydrological processes of watershed was also analysed. Daily streamflow and sediment yield data of years 2005–2006 were used for calibration and 2007–2008 for validation. Model performance was quite satisfactory during calibration and validation. The potential influences of mines were assessed by modelling an alternative scenario assuming nomines (unmined) for the period 2005–2010. Abandoned opencast mines altered the magnitude of hydrological processes of Olidih watershed. Increase in sediment yield by 14.29%, groundwater flow by 13%, evapotranspiration by 4% and decrease in surface runoff by 51.33% and water yield by 6% was observed as compared with no-mines scenario. Water samples from study area were collected and analysed to identify their suitability for domestic uses in pre-monsoon (PRM) and post-monsoon (POM) seasons. The results showed that surface water from 53.6% mineaffected area in PRM and 28.2% mine-affected area in POM season was not suitable for drinking purpose.