Assessment of morphological changes of river bank erosion using landsat satellite time-series images

Abstract

River morphology is one of the most important fields of river engineering and the study of the changes in the flow direction and cross-sections of a river. Over the past years, using the unique properties of remote sensing (RS) and satellite images, many studies have been conducted on rivers' morphological changes. In this study, the morphological changes of the river boundary displacement and the changes in river width resulting from deposition and erosion during 30 years period (1985 to 2015) in the Bazoft River, one of the North sub-basins of the Karun River basin in Iran, using 26 satellite images of TM, ETM+, and OLI Landsat in the ENVI 5.3 and ArcGIS 10.3 software have been assessed. The results indicated that the greatest change in the river bank takes place in the distance between 62 and 84 km from Karun-4 Dam to the upstream. Besides, analyzing long-term periods indicated that in the time intervals of 1985–1994, 1994–2005, and 2005–2015 the sediment had deposited along river banks. For 30 years, the river's average deposition and erosion levels areas are estimated to be 69.4 and 42.4 ha, respectively, meaning that ground with 27.1 ha is formed by virtue of deposition. According to the assessments, it was indicated that there is no significant difference between average deposition and erosion on the left bank in short periods, and the deposition bank is approximately 2% greater than bank erosion. However, on the right bank, the deposition level is approximately 8% greater than erosion, which is significant at a confidence level of 95%. The results of this study perfectly indicated the ability of sub-pixels and the use of water indicators in revealing the river form changes using Satellite Images Time Series (SITS).