Estimation of siltation in Tuirial dam: a spatio-temporal analysis using GIS technique and bathymetry survey

Dams are the source of power generation which also provide water supply for irrigation and other domestic needs. Siltation is the major issue, particularly in shortening the life span of the dams worldwide. Mizoram is highly fragile due to its undulating topography and loose sedimentary rock formations. Accumulated sediment is estimated to be high due to high run-off over steep slopes. This area lacks proper scientific studies on siltation estimation. An attempt was made in this study to estimate siltation at the micro-level in the Tuirial dam site, Kolasib district of Mizoram between 2016 and 2023 using advanced land observing satellite (ALOS) phased array type L-band synthetic aperture radar (PALSAR) digital elevation model (DEM) 2016, geographic information system (GIS) and remote sensing (RS) techniques, and by a bathymetry survey. The coordinates information and elevation data obtained from the bathymetry survey were interpolated for the generation of the triangulated irregular network (TIN) by interpolation. Again, in the same manner using ALOS PALSAR DEM at 12.5 m resolution, of the same bathymetry survey point elevation data was extracted for the generation of TIN. The total surface volume is computed as 17,295,827 m3 in 2016, and 19,872,177 m3 in 2023, and the rate of siltation is estimated to be 2,576,350 m3yr-1.