An investigation into longitudinal forms of gullies within the “Grand Canyon” of Bengal, Eastern India

Abstract

AbstractThe development of gullies is intrinsically linked with the growth of their principal channels. Analysis of the longitudinal form of these channels can provide insight into both the extent of badland formation within that catchment and the nature of the substrate. In this study, we examine the longitudinal profiles of the major gullies formed within the Gangani Badlands in Paschim Medinipur district of Eastern India, which is often referred to as the “Grand Canyon” of Bengal. These are examined using a very high‐resolution digital elevation model to extract the respective main gully catchments, map the stream network and derive the required information for statistical analysis of the gully longitudinal profile forms. Stream segment gradient indices were subsequently computed and related to the hardness of the substrate that was derived using a RockSchmidt rebound hammer. The effect of the ambient lateritic hardpan is seen to markedly influence the gully channel character, with most having steeper segments in the middle portion of their course, where the initial rills and minor gullies debouch over the high duricrust escarpment present here. Since gully development within lateritic terrain is a relatively less examined phenomenon worldwide, such investigations add to the relevant knowledge base.