Geomorphological units, their geohydrological characteristic and vertical electrical sounding response near Munger, Bihar

Abstract

Geomorphological mapping through satellite remote sensing coupled with geophysical electrical resistivity survey (vertical electrical sounding) gives very useful information about spatial and depth-wise variation of aquifer’s material, respectively. The present study area broadly falls between the Ganga river and Kharagpur hills (a northern limit of Chotanagpur plateau). These hills are highly folded and consist of quartzites and phyllites of Precambrian age group In the study area, cover material above the basement is the product of weathering, colluvial and fluvial processes of different ages. Geomorphologically, study area has been categorised into different classes i.e. denudo-structural hill, buried pediment, younger alluvial plain, recent flood plain and older alluvial plain. Broadly these classes represent the general ground-water prospects, but in detail, possibility of variation in ground-water prospects cannot be ruled out. In alluvial plain (younger/older) main target for ground-water exploration is sandy horizon. Similarly in buried pediment the main target is coarse-grained weathered material with fractured basement, not the total general thickness of cover material on the basement. In the present paper, authors have tried to analyse the spatial distribution of geomorphic classes and depth-wise variation of aquifer material within the same class for determining the target horizon for further detailed investigation, using remote sensing and electrical sounding.