Assessment of Sedimentation in Major Reservoirs of Hard Rock Terrain of India Using RS Technique

Abstract

Sedimentation in the reservoir reduces the storage capacity and its life. Hence, the periodic investigation is necessary to arrive at a realistic siltation index for planning of future reservoir projects in the basin. The conventional techniques of sediment quantification in a reservoir are cumbersome, costly and time consuming. With the advent of remote sensing techniques, it has become very cheap and convenient to quantify the amount of sedimentation in the reservoir. Therefore, in the present study, the assessment of the sedimentation in major reservoirs of hard rock terrain was carried out using the digital image processing of remotely sensed data of reservoirs in hard rock terrain of India. The remote sensing data acquired for various dates were analysed for estimating the reservoir water spread area as well as computing the capacity of reservoir. The annual rate of sedimentation and further loss in reservoir capacity are found more in case of Tungabhadra reservoir as compare to other reservoirs under study due to its drainage characteristics. The revised Elevation-Area-Capacity (EAC) curves developed for study reservoirs will be helpful to reservoir authority for planning the mitigation measures to enhance the capacity and its operation. The factors related to catchment characteristics influencing reservoir sedimentation were also analysed. Based on the analysis, it can be revealed that the rate of sedimentation is linearly correlated with size of the drainage area. KeywordsReservoir Sedimentation; Reservoir Capacity; Remote Sensing; Digital Image Processing