Estimation of Sediments in Rengali Reservoir, Odisha (India) Using Remote Sensing

Abstract

Reservoir sedimentation is a regular process and sequential path of sedimentation in reservoirs comprising of erosion, entrainment, transference, deposition and compaction of dregs carried into artificial lakes formed behind the dams. India houses 5334 large dams in function (2329 numbers before 1980) and 411 dams are in pipeline. The Rengali dam, functioned from 1984, that traps 50% of the total sediment load of the Brahmani River continues to thwart the growth and buffering of the Brahmani delta. Remote sensing (RS) and Geographical Information System (GIS) have emerged as powerful tools to create spatial inventory on Hydro-Bio-geo resources and the state of the environment. The RS/GIS and process-based modelling employed in spatial and dynamic assessment of loss in live storage of the reservoir by developing contour, aspect and slope map by using data received from LANDSAT sources. The sedimentation of the Rengali reservoir (functional from 1984) studied for three decades 1990-2000; 2000-2010 and 2010- 2020 by constructing contour, aspect and water spread area maps by using web based data (satellite downloads). The web based water spread area data analysed by GIS tool for integration, spatial analysis, and visual presentations. The results revealed that the decadal rate of sedimentation of Rengali reservoir is reducing with age. An appropriate reservoir operation and management system as per defined protocols considering sediment related problems is essential for controlling the ageing processes that may diminish the safety and shorten the reservoir life.