Estimation of Sediment Yield within Mining Watershed to Assess Impact of Mine Dumps Using Satellite Data: Modified Approach

Abstract

Opencast mining disturbs large areas of land, resulting in a decline in the groundwater table, increased sedimentation rates, and groundwater contamination. The sediment yield from the mined areas can be several times greater than from undisturbed areas. The sediment yields can be greater in the regions with large overburden (OB) dumps, which facilitate surface erosion because they consist of unconsolidated loose materials and induce changes in surface morphology. The present study proposes a modified approach using geoinformatics to estimate the sediment yield in a microwatershed dominated by coal mines and OB dumps. A modified equation has been proposed that uses the drainage and the vegetative cover, the major inputs required for sediment yield estimation. The sediment yields have been estimated for the years 1989 and 2007, during which the OB dump area increased significantly. Land use classes were extracted for 1989 and 2007, using multispectral Landsat and Indian remote sensing (IRS) satellite data. Sensitivity analysis was carried out to examine the performance of the modified approach. The outcome of the study corroborates the utility of multidate, multiresolution satellite data for the estimation of sediment yield. In the absence of field data, the study reveals that satellite data provides the information on the impact of the OB dumps on the quantities of the sediment yields as a result of the enhanced erosion rates. The results obtained in the present study of a mining dominated microwatershed will help administrators and authorities to take the necessary preventive measures for controlling the erosion through proper mine management.