Geomorphic changes in the Jhelum River due to an extreme flood event: a case study

Abstract

The unprecedented extreme flood occurred in Jhelum basin, India in the first week of September, 2014 due to continuous spell of high intensity antecedent rainfall. The rainstorm observed over the basin during the event was unprecedented in terms of accumulated rainfall. In this study, Operational Land Imager (OLI) Landsat images taken before and after flood were employed to assess the morphologic and geomorphic effects of the flood along both the sides of the Jhelum River. The total erosion and sedimentation for the study reach due to flooding were 278 and 2.7 ha respectively. The flow length and the average channel width were decreased by 500 m and 25 m respectively. The study reach was divided into meander loops (M), straight stretches (S), and island bars (B) based on sinuosity and braiding. The maximum erosion in the meander loops was observed in M5 section, B4 section in island bars, and S7 section in straight stretches of the river. The maximum erosion was observed in the riparian cover due to this flood. However, damage to the built-up cover was practically very limited to the selected river reaches due to the reinforced channel banks. It is evident from the findings of the erosion on different sections of the meander loops and straight reaches that as the sinuosity increases, the erosion also increases for a relatively significant areal extend of each land cover. This result gives insight to the incompetent management measures of riparian cover, which is a principal reason for the huge economic losses during flood.