Investigation of the watershed hydro-morphologic characteristics through the morphometric analysis: A study on Rayeng basin in Darjeeling Himalaya

Abstract

The analysis of morphometric parameters gives a precise scenario about the geomorphic characteristics and the hydrological behaviour of a drainage basin, especially in the areas where hydrological data are unavailable due to the absence of a gauging station or inaccessibility for harsh topographic conditions. So, the current study is aimed to investigate the hydro-geomorphic characteristics of the Rayeng basin in Darjeeling Himalaya. The extraction and analysis of the morphometric variables of the study area were done using remote sensing and GIS. The spatial disparity in drainage density, lineament density, stream frequency, texture ratio, and infiltration number has inferred that the Rayeng basin is carried a high runoff intensity and low infiltration rate on the upper reaches and an inverse situation in the lower reaches. The extracted ruggedness index and Melton's Ruggedness index indicate the unevenness of the topography and normal flow in the main channel in the Rayeng basin. A distinctive topographic diversity is also depicted by the basin's Topographic Positioning Index (TPI). A significant spatial variation of water availability in this basin is indicated by the Topographic Wetness Index (TWI); the depressed areas of the basin have higher TWI compared to the steep-sloped high land. The basin's hypsometric integral (HI) is inferred youthful stage. This basin has a good potentiality of water which can be sustainably used by the people of the lower reaches of the basin. This study will be helpful to assess the hydro-geomorphic characteristics of a drainage basin where hydrological data are not available.