Geomorphic evolution of the Dongar River Basin, Son Valley, Central India

The present study is an attempt to describe the geomorphic evolution of the Dongar River Basin, Son Valley, Central India. To achieve this target, a detailed field survey and morphometric analysis of the river have been carried out using Cartosat-DEM data with the help of ArcGIS 10 software. The basin area of the Dongar River is 35.17 km2 having trellis and sub-dendritic to dendritic drainage patterns. The Dongar River is designated as fourth-order basin and lower order streams mostly dominate in the basin with the drainage density value of 1.21 km−1. The stream order of the basin is predominantly controlled by physiographic and tectonic set-up of the study area. The slope of basin varies from 0° to 42.04° and is mainly controlled by the local geology and erosional cycles. The bifurcation ratio (Rb) for the studied basin varies from 1.58 to 4. The higher values of the bifurcation ratio, i.e., of second/third along with third/fourth order, reveal the regional geological and tectonic controls when river starts draining along the exposures of lower Vindhyan . The elongation ratio of the basin is 0.86 thus indicates high infiltration capacity, low runoff, and low-to-moderate slope of the river basin. The increase in stream length ratio from lower to higher order shows that the basin has reached mature geomorphic stage. The major trends of lineaments are ENE – WSW, i.e., almost analogous to Son-Narmada lineament suggesting that Son-Narmada lineament played an important role to control the drainage dynamics and evolution of the adjacent river basins. These features along the Dongar River and the orientation of the major lineaments suggest neotectonics, may be due to reactivation of the Son-Narmada lineament.