Regional Tectonic Signatures and their Effect on Soil Erosion in Northerly Flowing Cratonic Rivers, Central India

ABSTRACT North-flowing Indian cratonic rivers originate from an uplifted forebulge plateau. Hence, the southern boundary of the Gangetic plain has been claimed as a neotectonically active region. Despite low annual precipitation, the region experiences high rates of soil erosion and land degradation. Therefore, we evaluated geomorphometric indices, chi profiles, and the normalised Steepness Index ( ksn ) using a 30m SRTM DEM, and assessed soil erosion using the Revised Universal Soil Loss Equation (RUSLE) model to study this region. Our findings reveal that a higher bifurcation ratio (Rb) value of 6.3 is observed in the Son River, a stream length ratio (Rl) of 1.94 and a length-area relation (Lar) of 1724.75 in the Chambal River, a shape index (Sw) of 4.2 in the Betwa River, an elongation ratio (Re) of 0.69 in the Chambal River, and a circularity of 0.18 in the Betwa River, indicating tectonic signatures. The chi and ksn indices suggest that most rivers deviate from a graded profile, except for the Son and Banas rivers, which indicate a tectonically active region. The high value of the hypsometric integral and convex shape in the Hypsometric Curves (HC) of the Parbati catchment indicate a more active stage. The findings suggest the impact of neotectonic uplift in the forebulge region, as evidenced by the elevated soil erosion rate of 1.17 t/ha/yr.