Prioritization of miniwatersheds based on Morphometric Analysis using Remote Sensing and GIS techniques in a draught prone Bargur – Mathur subwatersheds, Ponnaiyar River basin, India

Morphometric analysis has been carried out on 781 sq.km area in the Bargur and Mathur subwatersheds. Based on All India Land area organization norms, the drainage network of the study area has been divided in to 10 miniwatersheds using 1:50,000 scale SOI toposheets and Landsat ETM satellite data. The Morphometric analysis of subwatershed has been carried out using GIS software. The drainage network exhibits dendritic drainage pattern. Stream order ranges from fourth to sixth order. Drainage density varies between 1.26 to 2.94 Km/Km². Texture ratio of drainage basins range between 2.59 to 15.46, and the miniwatersheds are classified as moderate to fine drainage texture excepting 4 miniwatersheds which are classified as fine to very fine drainage texture. The stream frequency of Bargur and Mathur subwatersheds ranges between 2.36 to 7.28. The stream frequency is low in most of the subwatersheds indicating low relief and high permeability, however, four subwatersheds show high stream frequency, indicative of high relief and low infiltration capacity of bedrock. The relief ratio ranges from 0.03 to 0.07. The bifurcation ratio range from 0.43 to 8.45, with a mean bifurcation ratio of 3.327 for entire basin, indicates that all miniwatersheds fall under normal basin category. The elongation ratio of miniwatersheds varies from 0.23 to 0.58, indicates miniwatersheds fall under oval and elongated pattern. Present study demonstrates the competence of remote sensing data coupled with GIS techniques in morphometric analysis. Based on the quantitative morphometric analysis, the study area has been classified into highly suitable, moderately suitable and poorly suitable for groundwater prospects.