Assessment of sediment distribution pattern in the Tungabhadra reservoir using satellite imagery

Abstract

In order to understand the dynamic aspects of suspended sediments in an inland water body, Tungabhadra reservoir on the Tungabhadra river in the Krishna basin was studied. The study has been carried out using Landsat MSS and IRS-1 A LISS-II images. Visual interpretation techniques have been used to obtain information on the location and extent of sediment distribution pattern in the water-spread area of the reservoir. It has been possible to monitor the seasonal fluctuations in the reservoir water-spread; measure corresponding fluctuation in the volume of water in the reservoir, and study seasonal changes in the suspended sediment distribution pattern in the reservoir. An attempt has also been made to prepare area capacity curve for the reservoir. Semi-quantitative assessment of sediment deposits between reservoir levels were made considering water spread area from the satellite images (May 1986, April 1987, Jan. 1988, Jan. 1989 and March 1989) and sedimentation survey report of KERS 1985, (Karnataka Engineering Research Station). The results indicated that the high Concentration of sediments is at the western confluence of the Tungabhadra river. On the basis of tonal variation as observed, the reservoir could be divided into four major zones, viz., very high and high at the river confluence, moderate at the periphery and low at the dam site.