MORPHOMETRIC ANALYSIS OF SUB-WATERSHEDS IN THE PAVAGADA AREA OF TUMKUR DISTRICT, SOUTH INDIA USING REMOTE SENSING AND GIS TECHNIQUES S. SRINIVASA VITTALA * , S. GOVINDAIAH ** AND H. HONNE GOWDA * * Karnataka State Remote Sensing Applications Center, Koramangala, Bangalore-560033, India ** Department of Geology, University of Mysore, Manasagangothri, Mysore-570 006, India E-mail : vittala_99@rediffmail.com Photonirvachak Journal of the Indian Society of Remote Sensing, Vol. 32, No. 4, 2004 Received 7 January, 2004; in final form 16 August, 2004 ABSTRACT The study area covers 570 km 2 comprising of 9 sub-watersheds (Dalavayihalli, Maddalenahalli, Talamaradahalli, Puluvalli tank, Nagalamadike, Gowdatimmanahalli, Naliganahalli, Devadabetta and Byadanur) range from 49 to 75 km 2 forming part of Pennar river basin around Pavagada. The drainage network of 9 sub-watersheds was delineated using remote sensing data - Geocoded FCC of bands - 2 3 4 of IRS 1 C and 1 D (LISS III+PAN merged) on 1:50,000 scale and SOI topomaps were used as reference. The morphometric analysis of 9 sub-watersheds has been carried out using GIS softwares - ArcInfo and ArcView. The drainage network shows that the terrain exhibits dendritic to sub-dendritic drainage pattern. Stream orders ranges from fourth to fifth order. Drainage density varies between 1.55 and 2.16 km/ km 2 and has very coarse to coarse drainage texture. The relief ratio range from 0.006 to 0.021. The mean bifurcation ratio varies from 3.21 to 4.88 and falls under normal basin category. The elongation ratio shows that Devedabetta sub-watershed possesses circular shape while remaining sub-watersheds mark elongated pattern. Hence from the study it can be concluded that remote sensing techniques proved to be a competent tool in morphometric analysis. Introduction Earlier, morphometric analysis using remote sensing techniques has been well attempted by Srivastava and Mitra, 1995; Srivastava, 1997; Nag, 1998; Agarwal, 1998 and all have arrived to the conclusion that remote sensing technique has emerged as a powerful tool in the recent years. Satellite remote sensing has the ability of obtaining synoptic view of large area at one time and very useful in analyzing the drainage morphometry. The study comprises of 9 sub-watersheds draining into