Impact of Sarangkheda Dam Construction on the Downstream Reach of Tapi River of Nandurbar District, Maharashtra

This study has investigated the impact of Sarangkheda Dam construction on the downstream reach of the Tapi River since 1985. From the Sarangkheda Dam to the Sarangkheda Gauging Station, close to Sarangkheda Village in the Nandurbar District of Maharashtra, the study extent is 8.5 km long. This study describes changes in water discharges, sediment loads, mean channel-bed elevation, bed degradation, and channel width downstream from the Sarangkheda Dam constructed on the Tapi River. The construction of the Sarangkheda Dam in the Nandurbar District of Maharashtra involved utilizing geographic information system (GIS) analysis, which focused on a time series of Landsat satellite images obtained in 1996, 2006, 2010, and 2019. The primary objective of this analysis was to assess the variations in the width of the non-vegetated active channel, bed elevation, and sediment load of the Tapi River profile. From 17.48 cubic meters in billion in 2006 to 3.28 cubic meters in billion in 2014, the yearly flow volume dropped. Following the construction of the Sarangkheda Dam, the yearly flow volume from pre-dam to post-dam averaged 5.93 cubic meters in billion across the downstream, and from 1985 to 2014, the reach's mean bed elevation decreased from 112.74 to 111.35 m. The 8.5 km length downstream of the Sarangkheda Dam should be most affected by the changes in bed elevation. The Sarangkheda Dam typically reduced flood peaks. However, because a large volume of water is discharged when the dam releases water, other aspects of the post-dam water discharge characteristics change from time to time. The degree of bed erosion in the river channel ranged from little to about 1.25 m over the 8.5 km length downstream of the Sarangkheda Dam cross sections that were studied. Typically, most of the decrease occurred post to the construction of the dam. The channel width in the downstream reach of Sarangkheda Dam can undergo changes, including increases, decreases, or maintaining a constant width. When confronted with considerable variability, the temporal alterations in streambed elevation and channel width at a specific location may frequently be elucidated by analyzing cross-sectional data and satellite imagery.