Analysis of Sedimentation Deposition in Morbe Reservoir by Using RS and GIS

Abstract

The reduce in the storage volume due to sediment deposits in the reservoir at different level over a period of time can be related with the decrease in water diffusion zone at different elevation. This study shows the use of RS and GIS to estimate reservoir sediment deposits. The 2007 regional capacity curve (water storage) is now used due to the fact basis for the 2017-18 sediment assessment. This will help us assess the precipitation in the long run. The digital processing was performed using Arc-GIS software. NDWI (normalized difference water index) is used to describe the features of water and progress the existence of water pixels in the Landsat-8 satellite images of the Morbe dam. The water diffusion zone of the water storage basin on the specific height of the day of the satellite passes which help to form an elevation capacity curve. The linear interpolation/ extrapolation method is used to evaluation of the water diffusion zone of the Morbe dam on the different heights in 2007. The different elevations are taken to estimate the storage capacity in live zone of the water basin between the contour lines form by the water body with the help of Prizmoidal formula. After that revised reservoir capacity is differentiated with the capacity at the begin in 2007 to achieve capacity loss from 2007 to 2018 (i.e. 11 years). The loss in capacity of the reservoir is the sediment deposited at that elevation. As a result, the show the capacity of live storage zone is reduced from 190.89 Mm3 to 186.251 Mm3, indicating a total capacity loss 4.6390 Mm3.The loss of capacity 2.4302% in 11 years. If the sedimentation occurs linearly then the rate of sedimentation is estimated to be 0.4217 Mm3 year-1. Keywords: Arc-GIS, Prizmoidal Formula, Sedimentation, RS and GIS, Normalized Difference Water Index (NDWI).