Impact assessment of coal mining on river water and groundwater and its interaction through hydrological, isotopic characteristics, and simulation flow modeling

Abstract

Impact assessment of coal mining of Gare IV/6 Coal Block (GCB) on river water (Kelo River) and groundwater and the interaction between them were studied through hydrological studies like water-level monitoring, short and long-term river flow measurements, isotopic characteristics, and groundwater flow modeling. The hydrological study reveals that the groundwater flow is towards the Kelo River and the river is acting as effluent in nature. The flow direction is parallel to Kelo River in the downstream of the GCB. The isotopic study suggests that the Kelo River water is enriched with δ 18O/16O ratio as compared to watershed samples. Flow modeling suggests that the Kelo River, which is adjacent to the boundary of GCB, may contribute 88.38 m3/day of groundwater. The groundwater effluence forms a meager component of the total groundwater effluence estimated for the entire length of the Kelo River passing through the study area. Based on the groundwater flow model results it is suggested that the proposed mining operation in GCB will not have any impact on the Kelo River water flow. The suspected seepage from the Kelo River flooding on the GCB is unlikely as the hydraulic gradient is towards the Kelo River. It is suggested to have a buffer zone and an embankment between Kelo River and GCB to prevent flooding from river water breaching. The present study provides an overall understanding of the hydrogeological conditions in and around mining area which will help in safe mining operations so that any hazard or threat to the local community may be prevented.