Morphometric Analysis of Tectonically Active Bhimtal-Naukuchiatal Lake Basin, Kumaun Himalaya

Abstract

Bhimtal-Naukuchiatal region, which is an integral part of the Kumaun Lesser Himalaya, is sensitive to natural disasters and has a fragile environment as a result of neotectonic activity along the thrust and secondary thrust/faults. With regard to neotectonic activity, this study aims to comprehend the tectonic instability of the basin. Morphometric analysis is a computable research of landforms that is crucial to understanding how the landscape has evolved in response to nearby tectonic activity. In present exercise we have calculated ten morphometric indices, viz., Valley floor width-height ratio (Vf), Hypsometric Integral (HI), Stream-Length gradient Index (SL), Bifurcation ratio (Rb), Drainage density (Dd), Stream Order (Sµ) and average Sinuosity (S), Relief (H), steepness (Ksn), Chi integral (?) and Asymmetric Factor (AF). The result shows low values of Vf indicate high upliftment rate, more incision and less channel down cutting. Most morphometric results suggest tilted basin, resulting in V-shaped valleys and a distorted and unstable longitudinal profile, which indicate the area is governed by both tectonics and lithology. The field geomorphic features along with the software based calculations suggest that the Bhowali-Bhimtal-Naukuchiatal is tectonically active zone.