Precipitation change assessment over upper Bagmati river basin using regional bias corrected GCM data

Morphometric analysis of a watershed provides a quantitative description of the drainage system which is an important aspect of characterization of watershed. The analysis requires measurement of linear features, aerial aspects, gradient of channel network and contributing ground slopes of the drainage basin. The morphometric characteristics at the watershed-scale may contain important information regarding its formation and development because all hydrologic and geomorphic processes occur within the watershed. In this study morphometric property of the Bagmati River Basin (BRB) was investigated using different morphometric attributes and hypsometric analysis in order to investigate geomorphic development of the river basin, in an active tectonic zone. DEM has been prepared from the contour and spot height data using digital topographic maps of 1:25000-scale acquired from the Department of Survey, Nepal. The main stem Bagmati River is the eighth order perennial river that stretches for 206 km with an elongated catchment of area 3761 sq. km. It consists of 39 sub-basins of fourth order and higher. The study shows that the drainage system of the BRB is attaining a mature stage from a youth stage from lower order streams to the higher order streams in geomorphic development process. Some exceptions occurred at higher order stream segments, where drainage development seems to control by structure and lithology. According to the analytical results, erosional stage and level of tectonic activity of sub-basins differ from each other. Generally, the lithology and geological structure seems to control the drainage texture and relief of the BRB. The river system within the Kathmandu Valley is attaining maturity having meandering channels with wide flood plains, whereas rivers of the Lesser Himalaya and the Siwaliks are at youth stage with erosional potential. The downstream part of higher order stream segments are in mature stage having potential for lateral erosion and meander migration. Therefore, the Bagmati River stretch, especially the eight order one poses vulnerability to bank erosion.

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Assessment of Flood Hazard and Agriculture Damage Under Climate Change in the Bagmati River Basin of Nepal

International Journal of Environment ◽

10.3126/ije.v8i2.25508 ◽

2019 ◽

Vol 8 (2) ◽

pp. 55-69 ◽

Cited By ~ 1

Author(s):

Badri Bhakta Shrestha

Keyword(s):

River Basin ◽

Flood Risk ◽

Damage Assessment ◽

Growth Stage ◽

Flood Hazard ◽

Flood Damage ◽

Flood Risk Management ◽

Flood Inundation ◽

Flood Hazards ◽

Bagmati River

Assessment of flood hazard and damage is a prerequisite for flood risk management in the river basins. The mitigation plans for flood risk management are mostly evaluated in quantified terms as it is important in decision making process. Therefore, analysis of flood hazards and quantitative assessment of potential flood damage is very essential for mitigating and managing flood risk. This study focused on assessment of flood hazard and quantitative agricultural damage in the Bagmati River basin including Lal Bakaiya River basin of Nepal under climate change conditions. Flood hazards were simulated using Rainfall Runoff Inundation (RRI) model. MRI-AGCM3.2S precipitation outputs of present and future climate scenarios were used to simulate flood hazards, flood inundation depth, and duration. Flood damage was assessed in the agricultural sector, focusing on flood damage to rice crops. The flood damage assessment was conducted by defining flood damage to rice crops as a function of flood depth, duration, and growth stage of rice plants and using depth-duration-damage function curves for each growth stage of rice plants. The hazard simulation and damage assessment were conducted for 50- and 100-year return period cases. The results show that flood inundation area and agricultural damage area may increase in the future by 41.09 % and 39.05 % in the case of 50-year flood, while 44.98 % and 40.76 % in the case of 100-year flood. The sensitivity to changes in flood extent area and damage with the intensity of return period was also analyzed.

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Water poverty in upper Bagmati River Basin in Nepal

Water Science ◽

10.1016/j.wsj.2016.12.001 ◽

2017 ◽

Vol 31 (1) ◽

pp. 93-108 ◽

Cited By ~ 16

Author(s):

Jay Krishna Thakur ◽

Mahesh Neupane ◽

Anju Andezhath Mohanan

Keyword(s):

River Basin ◽

Bagmati River

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Atmospheric and Terrestrial Water Balances of Labrador's Churchill River Basin, as Simulated by the North American Regional Climate Change Assessment Program

ATMOSPHERE-OCEAN ◽

10.1080/07055900.2015.1029870 ◽

2015 ◽

Vol 53 (3) ◽

pp. 304-318 ◽

Cited By ~ 3

Author(s):

Jonas Roberts ◽

Ken Snelgrove

Keyword(s):

Climate Change ◽

River Basin ◽

North American ◽

Regional Climate ◽

Regional Climate Change ◽

Change Assessment ◽

Assessment Program ◽

The North ◽

Terrestrial Water ◽

Climate Change Assessment

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Hydroclimatological changes in the Bagmati River Basin, Nepal

Journal of Geographical Sciences ◽

10.1007/s11442-013-1032-8 ◽

2013 ◽

Vol 23 (4) ◽

pp. 612-626 ◽

Cited By ~ 16

Author(s):

Yam Prasad Dhital ◽

Qiuhong Tang ◽

Jiancheng Shi

Keyword(s):

River Basin ◽

Bagmati River

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Long-term precipitation change by hourly data in Haihe River Basin during 1961–2004

Science China Earth Sciences ◽

10.1007/s11430-011-4232-z ◽

2011 ◽

Vol 54 (10) ◽

pp. 1576-1585 ◽

Cited By ~ 7

Author(s):

ShuiQing Yin ◽

Ge Gao ◽

WeiJing Li ◽

DeLiang Chen ◽

LiSheng Hao

Keyword(s):

River Basin ◽

Precipitation Change ◽

Haihe River Basin ◽

Haihe River ◽

Hourly Data

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Textural and compositional variation of sand along the Manahara-Bagmati river basin, Kathmandu Valley

Journal of Nepal Geological Society ◽

10.3126/jngs.v23i0.31865 ◽

2001 ◽

Vol 23 ◽

Author(s):

Naresh Kazi Tamrakar ◽

Hari Nandan Gurmaita

Keyword(s):

River Basin ◽

River System ◽

Compositional Variation ◽

Humid Climate ◽

Quartz Content ◽

Rock Fragments ◽

Grain Sizes ◽

Size Grade ◽

The Mean ◽

Bagmati River

The Manahara-Bagmati river basin is located in a humid climate and has a 51 km long low gradient profile. It collects sediments from metamorphic, metasedimentary, and fluvio-lacustrine sources. The sediment samples collected from 17 localities were studied texturally and compositionally to infer how sediment modifies due course of transport and whether the trends are interfered by mixing, recycling, and weathering. For this purpose, two size grades (i.e., 0-1ϕ and 2-3ϕ) were studied. Between them, the trends were more conspicuous in the 0-1ϕ sand grade. Mean (M2) and median (M6) grain sizes increase downstream exponentially. Sorting (σ1) also improves along the river course. Quartz content gradually increases downstream, whilst feldspars and rock fragments decrease remarkably along the river course. Rapid dilution of feldspars and rock fragments (from coarser size grade) occurs after 27 km of transport. The Modified Maturity Index, which ranges from 19.8 to 214, increases from the Manahara to Bagmati River sands. The mica content in the Bagmati River is from 2 to 8 times higher than in the Manahara River. Within the studied river course, the mean projection sphericity (ψp) of quartz remains high (0.80 in average) but does not show any consistent trend. The mean roundness (ρ) of the 0-1ϕ sand grade increases conspicuously against the distance of transport. The majority of samples belong to submature class. Local influx of sediments and recycling are profound from Sankhu to Sanothimi and from Chobhar to Hasdol. Rapid weathering of labile grains is inferred in the middle reach of the Manahara- Bagmati river system (i.e., between Sanothimi and Chobhar).

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