Abstract:
A reservoir is an integral component of a water resources system. Periodic evaluation of sediment deposition pattern and assessment of available storage capacity of reservoirs is an important aspect of water resources management. The conventional techniques of quantification of sediment deposition in a reservoir, like the hydrographic surveys and the inflow-outflow methods, are cumbersome, costly and time consuming. Further, prediction of sediment deposition profiles using empirical and numerical methods requires large amount of input data and the results are still not encouraging.
Due to sedimentation, the water-spread area of reservoir at various elevations keeps on decreasing. Remote sensing technique, through its spatial, spectral and temporal attributes, provides synoptic and repetitive information on water-spread area of a reservoir. By use of remote sensing data and a geographic information system in conjunction, the temporal change in water-spread area can be analysed to evaluate the sediment deposition pattern in a reservoir. A case study, related to the assessment of sediment deposition in Bargi reservoir, M.P. State, India, is presented. The reservoir was completed in the year 1988 and no hydrographic survey has yet been carried out. Under these circumstances, the sedimentation assessment using satellite data can guide the dam operators in updating the elevation-area- capacity table of the reservoir. The images of nine dates of IRS-1C satellite, LISS-III sensor have been analysed using the ERDAS/IMAGINE software. The sedimentation rate in the zone of study comes out to be about 0.023 ha-m/sq. km/year.
