Morphometric Analysis of Chilenahalli Micro-watershed in the North-eastern Dry Zone of Karnataka using GIS and Remote Sensing Techniques

Abstract

The structure and landform of watershed and their associated stream networks are described mainly by their morphometric parameters and Watershed analysis based on morphometric parameters is very important for watershed planning, since it gives an idea about the basin characteristics regarding slope, topography, soil condition, runoff characteristics, surface water potential and quantify the linear, areal and relief aspects of watershed. Geographic information system and remote sensing techniques were employed for the identification of morphological features, drainage pattern and its planning in basin area. The Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) 30m resolution was used to digitize study watershed and generate drainage pattern and analysis done using GIS software and excel spreadsheet. The study reveals that Chilenahalli micro-watershed designated as 4thstream order and drainage indicate dendritic pattern with mature geomorphic stage and stream order verifies the Horton’s law of stream number. The Mean Bifurcation Ratio was found to be 4.46, which indicates low rainfall, shallow weathering and low dissection of the valley and it shows low to medium relief aspect during investigation of the basin. This can be visualised using DEM, relief ratio, ruggedness number, and slope maps of the study area. The drainage density was found to be 2.13 km/km2which indicate a low class Dd value, thereby indicating a poorly drained watershed with low response to hydrological parameters. The texture ratio of the micro-watershed is 3.52, which indicated coarse texture of drainage basin and the values of Form Factor, Circulatory ratio and Elongation ratio may imply an oval shape of the basin with a slightly elongated main stream and the length of overland flow values in this study is 0.23 km which shows moderate infiltration and percolation characteristics of soil. The study which also helps in planning erosion control strategy, prioritization of watershed and management practices for soil and rainwater conservation. The research study helps to formulate the selection and adoption of crop management practices by preparing soil map of the watershed in future.