Abstract

Glacier systems are important components of the hydrological cycle and a major source of meltwater and sediment flux that controls the river ecology, water quality, and hydropower generation in the Indian Himalayan Region (IHR). Thus, understanding short- and long-term changes in water and suspended sediment (SS) dynamics is crucial in highly sensitive pro-glacial Himalayan Rivers. In the present study, the Chandra River basin in Western Himalaya was chosen to study river discharge, SS transport dynamics, physical erosion rate, and their governing factors for the 2017 melting season (May–September). The daily mean water discharge and SS concentration in the Chandra River was 260.7 m³s⁻¹ and 775.5 mgL⁻¹ with maximum discharge and SS flux in the month of July. The air temperature showed significant relationship with the river discharge (R² = 0.67; n = 156; p < 0.001), which in turn controlled the SS export in the basin (R² = 0.86; n = 130; p < 0.001). An anticlockwise sediment-discharge hysteresis during peak flow conditions suggest exhausted sediments or large distance of sediment transport (>100 km) from the upper glacierized region to the end of the basin. Statistical analysis of SS particle size showed poorly sorted immature grains with a dominance of silt particles (85%), followed by sand (8.5%) and clay (6.5%). The SS estimates revealed a total suspended sediment yield of 1285 tons km⁻² yr⁻¹ and physical erosion rate of 0.47 mm yr⁻¹. Considering the socio-economic importance of the Himalayan region, the present study will help to evaluate the water and sediment budget of the Chandra River, Western Himalaya and to establish their relationship to the meteorological conditions in the basin.

Research Highlights

• The total water discharge and suspended sediment flux during ablation period (May–September 2017) in the Chandra River were 3536 MCM and 3 million tons.

• Overall, the suspended sediment were composed of silt size particles (85%) followed by sand (8.5%) and clay size (6.5+%) particles.

• The suspended sediment estimates revealed a total suspended sediment yield of 1285 tons km² yr^–1 and physical erosion rate of 0.47 mm yr^–1

• This study will be useful in understanding the SS cycling from the Himalayan region and to build robust models for future projections.

中文翻译：

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喜马拉雅西部钱德拉河的排水和悬浮泥沙动力学

摘要

冰川系统是水文循环的重要组成部分，是控制印度喜马拉雅地区（IHR）河流生态，水质和水力发电的融水和泥沙通量的主要来源。因此，在高度敏感的冰川前喜马拉雅河流域，了解水和悬浮沉积物（SS）动力学的短期和长期变化至关重要。在本研究中，选择喜马拉雅西部的钱德拉河盆地来研究2017年融化季节（5月至9月）的河流流量，不锈钢运输动力学，物理侵蚀速率及其控制因素。钱德拉河的日平均排水量和SS浓度为260.7 m ³ s ^-1和775.5 mgL ^-1在7月份最大流量和SS通量。气温与河流流量呈显着关系（R ² = 0.67；n = 156；p <0.001），进而控制了流域内SS的出口（R ² = 0.86；n = 130；p<0.001）。在峰值流量条件下，逆时针的泥沙排放滞后现象表明，泥沙已耗尽，或者从上部冰川区到盆地末端的泥沙输送距离（> 100 km）较远。对SS粒径的统计分析显示，未成熟颗粒的分类较差，主要是淤泥颗粒（85％），其次是沙子（8.5％）和粘土（6.5％）。SS估算显示，悬浮泥沙总产量为1285吨km ^-2 yr ^-1，物理侵蚀速率为0.47 mm yr ^-1。考虑到喜马拉雅地区的社会经济重要性，本研究将有助于评估喜马拉雅西部钱德拉河的水和沉积物收支状况，并建立它们与盆地气象条件的关系。

研究重点

• 钱德拉河消融期间（2017年5月至9月）的总排水量和悬浮泥沙通量为3536 MCM和300万吨。

• 总体而言，悬浮的沉积物由粉粒大小（85％），沙子（8.5％）和黏土大小（6.5 +％）的颗粒组成。

• 悬浮泥沙估算显示，悬浮泥沙总产量为1285吨km ² yr ^–1，物理侵蚀速率为0.47 mm yr ^–1

• 这项研究将有助于理解来自喜马拉雅地区的SS循环，并为未来的预测建立可靠的模型。