Volume No. 3 Issue No.: 4 Page No.: 1238-1245 April-June 2009




Rahul Kumar Jaiswal*, T. Thomas, R.V. Galkate, S. Singh1 and T.R. Nayak2

1. National Institute of Hydrology, GPSRC, 567, Manorama Colony, Sagar, M.P. (INDIA)
2. Narmada Control Authority, Vijay Nagar, Indore, M.P. (INDIA)


Received on : March 30, 2009




An understanding of quality and quantity of sediment deposits in reservoir is necessary for effective reservoir and basin management. Sedimentation affects both the useful life and aesthetic quality of a reservoir. The conventional methods of sediment assessment are laborious, costly, time consuming and require experienced manpower and sophisticated instruments. The digital image processing technique of remotely sensed data is easy, less costly and subjective of minimum human errors can be used for routine assessment of sedimentation in reservoirs. In the present paper, an attempt has been made to estimate the revised capacity of Ravishankar Sagar reservoir on river Mahanadi in Chhattisgarh (India). The catchment area of reservoir up to dam side is 3670 Sq. km. The designed gross and live storage of the reservoir are 909.32 MCM and 766.32 MCM respectively. To cover the whole range of live storage, ten scenes of LISS III (IRS-1D) have been selected and normalized deviation water index (NDWI) and slicing have been used to identify the water pixels. The revised water spread areas determined fron digital image processing have been used to estimate revised capacity at different levels. From the analysis of the results, it has been observed that 45.93 M. cum of gross storage and 31.00 M. cum. of live storage have been lost in last 24 years (1979 to 2003). If the rate of sedimentation in the reservoir is assumed as constant over the period of 24 years, the rate of silting may come out as 1.91 M. cum/year or 191 ha-m/year.


Keywords : Sedimentation, Water spread, Digital image processing, Normalised difference water index (NDWI), Slicing, Cumulative capacity.