Assessment of sedimentation in pong (Rana Pratap Sagar) reservoir using digital image processing technique

87-90All lakes created on natural rivers are subjected to reservoir sedimentation. Sedimentation in the reservoir is one of the principle factors. Sedimentation reduces the storage capacity. When the flow of a river is stored in a reservoir, the sediment settles in the reservoir and reduces its capacity. Reduction in the storage capacity of a reservoir beyond a limit hampers the purpose for which it was designed. Thus, assessment of sediment deposition becomes very important for the management and operation of such reservoirs. Some conventional methods, such as hydrographic survey and inflow – outflow approaches, are used for estimation of sediment deposition in a reservoir, but these methods are eumbersome, time consuming and expensive. Therefore an effective and time consuming technique, remote sensing approach has been attempted for this study. This method has been used for the assessment of sediment in pong reservoir created on the Beas river in the low foothills of Himalaya on the northern edge of Indo Gangetic plain, located in the Kangra district, Himachal Pradesh. A method has been developed, based on spectral mixture analysis, to estimate the concentration of suspended sediment in Reservoir from IRS (P6) LISS – III images. Paper represented the reservoir’s live storage capacity was 7290 M.cum and dead storage capacity was 8570 M.cum. The reservoir’s water spread area at full reservoir level (FRL) was 240 sq. km and the catchment area of its associated river Beas is about 12377.496 sq. km up to pong dam. Eight dates of IRS (P6) LISS – III data (from 10 oct. 2008 to 4 July 2009) between 426.720 m and 388.696 m water level were used to assess temporal and spatial patterns of lake area and dimensions of suspended sediment concentration in pong Reservoir. The Normalize Different Water Indices (NDWI) approach was used for delineating water spread area of reservoir. Revised live storage was estimated as 7233.622 M. cum. The water-spread area at FRL was 246.356 Mm2. The estimated sediment yield was 18.20 Mm3 in the live storage area. The study also illustrates the advantages of remote sensing and demonstrates the value of IRS (P6) LISS – III data for use in mapping geographic variations in water area and major flood event. This paper presents research results that help to better understand of this physical phenomenon, which contributes to reservoir sedimentation