Hydrogeomorphic assessment of badlands in part of the Mandakini River watershed, Chitrakoot, India

Abstract

Badlands are a hydrogeomorphological feature with operative processes leading to intense erosion. This study utilizes the morphometric methods with the help of remote sensing data in a GIS environment to determine the characteristics of the badlands of Mandakini River watershed and their interpretation to explore the factors responsible for the formation of the typical landforms. Objective interpretation of morphometric data of badlands with the help of statistical Pearson’s correlation coefficient (PCC) and dendrogram cluster may be made to emphasize the controlling factors. The morphometric parameters like the total number of streams (Nu), bifurcation ratio (Rb), drainage density (Dd), drainage frequency (Fs), drainage texture (Dt), and infiltration number (If) and their correlation in the study area plays a significant role in the advancement of rills and gullies. In the present area, the total number of streams (Nu) is very significantly related with the lengths of the first-order (L1), the second-order (L2), and the third-order streams (L3) along with the total stream length of all orders (Lu) in the third-order and the fourth-order sub-watersheds. Bifurcation ratio (Rb) is strongly correlated with L1, L2, L3, L4, and drainage texture (Dt) in the fourth-order sub-watershed. These correlations insinuate a tectonic influence in the basin and show an ultrafine drainage texture that ultimately forms badland topography. The relation between Dd-Lg-C-If-Rn produces a self-enhancing system of badland development, which promotes erosion in the area under study. These correlations provide a well-figured observation of the sub-watershed that, due to the increase in infiltration number (If), the drainage density (Dd) also increases, which leads to enhancement of channel cutting and erosion rates (low Lg and C value). This correlation coefficient of Rn is moderately low, indicating a single storey type of badlands. The badlands seem to have formed owing to setting up of self-enhancing erosive system on paleo wetlands, as evidenced by the presence of calcretes. Calcretes have been related to the presence of wetlands’ conditions. These have been related to fall in water levels, therefore, indicating much higher water levels nearly close to ground surfaces before setting up badlands conditions. Thus, the badlands which have shallow calcretes horizons can be said to have been wetlands in the past.