Evolutionary characteristics of meander cut-off- A hydro-morphological study of the Jalangi River, West Bengal, India

摘要

Formation of meander cut-off focuses some distinct migratory nature of the main channel over time and through the application of quantitative indices as cut-off ratio and diversion angle, the process of formation has been explained through its evolutionary stages. Comparative study of hydrological and morphological characteristics between the cut-off lakes and the main Jalangi depict that the main channel was active than the present and it is going to decay with time. These cut-off lakes are evident as the past hydrological characteristics of the channel. There are three meander bends have been identified among the selected 61 curves which have high tendency of cut-off formation near future. The main controlling components are shear stress, radius of curvature, and tortuosity which have been considered to quantify the mechanism in positive and negative perspective. It will help to identify more possible cut-off lakes near future. This morphological dynamism is distinctly interlinked with the remarkable land transformation in the last 25 years. The changing behavior of land utilization are characterized by huge increase of cultivated lands and settlement which have mostly converted from uncultivated waste lands, agricultural wet lands (seasonaly used), and water bodies respectively.