Abstract

This study intends to scrutinise the style and mechanism of the avulsion events in the Torsa River flowing across the Himalayan Foreland Basin (HFB) through analysing its response to the topographic and hydrological controls. A scientific investigation has been done planting the major thrust on the process geomorphological approach with an obligatory amount of quantification of the process and associated parameters. The investigation is heavily dependent on the available multi-temporal satellite images, set of available hydrological datasets and on-field survey of the topography and geomorphic markers related to past avulsion events in Torsa River between 1968 and 2017. The planimetry of avulsion and the avulsion style ratio has been applied to the occurred avulsion events in the course of Torsa during the said duration to study the underlying mechanism and associated sensitiveness to the given environmental setup. The topographic factors were found as an important controller of the avulsions in the course of river Torsa as the nature of the fluvial process and the physical setup differs significantly over the varied physiographic extents on the HFB. The studied avulsion events were found of annexation type and irrespective of the planform character, a tendency of forming a straighter course corresponding to topographic aptness.

Research Highlights

• The style of avulsion associated within a hyper-avulsive perennial river, Torsa, on the Himalayan Foreland Basin.

• The underlying mechanism of channel avulsion in the course of Torsa over the different physiographic extents ( i.e., Piedmont and Northern plains).

• A process response analysis for the avulsion events with its sensitivity to hydrological and floodplain topographic components.

中文翻译：

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Torsa 河道的河道撕脱及其对喜马拉雅前陆盆地地形和水文控制的响应

摘要

本研究旨在通过分析流经喜马拉雅前陆盆地 (HFB) 的 Torsa 河对地形和水文控制的响应，仔细研究其撕裂事件的类型和机制。已经完成了一项科学调查，主要推动了过程地貌学方法，并强制量化了过程和相关参数。调查在很大程度上依赖于可用的多时相卫星图像、一组可用的水文数据集以及与 1968 年至 2017 年间托萨河过去的撕毁事件相关的地形和地貌标记的现场调查。撕脱面积测量法和撕脱方式比率已应用于在上述期间 Torsa 过程中发生的撕脱事件，以研究潜在机制和对给定环境设置的相关敏感性。由于河流过程的性质和物理设置在 HFB 的不同地貌范围内存在显着差异，因此地形因素被认为是 Torsa 河河道撕裂的重要控制因素。研究的撕脱事件被发现是吞并型的，无论平面特征如何，都有形成与地形适应性相对应的更直路线的趋势。由于河流过程的性质和物理设置在 HFB 的不同地貌范围内存在显着差异，因此地形因素被认为是 Torsa 河河道撕裂的重要控制因素。研究的撕脱事件被发现是吞并型的，无论平面特征如何，都有形成与地形适应性相对应的更直路线的趋势。由于河流过程的性质和物理设置在 HFB 的不同地貌范围内存在显着差异，因此地形因素被认为是 Torsa 河河道撕裂的重要控制因素。研究的撕脱事件被发现是吞并型的，无论平面特征如何，都有形成与地形适应性相对应的更直路线的趋势。

研究亮点

• 与喜马拉雅前陆盆地超侵蚀性多年生河流 Torsa 相关的侵蚀方式。

• Torsa 过程中不同地理范围（即皮埃蒙特和北部平原）的通道撕脱的潜在机制。

• 对水文和泛滥平原地形成分敏感的撕脱事件的过程响应分析。