Future projection of cryospheric and hydrologic regimes in Koshi River basin, Central Himalaya, using coupled glacier dynamics and glacio-hydrological models

Khadka, Mira; Kayastha, Rijan Bhakta; Kayastha, R. B.

doi:10.1017/jog.2020.51

Cited by 33 publications

(18 citation statements)

References 48 publications

(70 reference statements)

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“…Twentyeight percent of the Budhigandaki River Basin is covered with snow and less than one percent (315 km 2 ) is covered with glaciers. In the upper subbasins, the contribution of the glacier melt might affect the total runoff to some extent [95][96][97][98] whereas our area of interest lies in the lower part of BRB near Arughat (elevation 540 masl), where the contribution of glacier melt is insignificant in the total runoff. Past studies have modeled glacier melt in high altitude catchments above 3000 masl (for e.g., [95,97]) in which the calibration stations are also located in high elevations (Langtang at 3670 masl; catchment area 353 km 2 ).…”

Section: Discussionmentioning

confidence: 99%

Application of SWAT in Hydrological Simulation of Complex Mountainous River Basin (Part I: Model Development)

Marahatta

Devkota

Aryal

2021

Water

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The soil and water assessment tool (SWAT) hydrological model has been used extensively by the scientific community to simulate varying hydro-climatic conditions and geo-physical environment. This study used SWAT to characterize the rainfall-runoff behaviour of a complex mountainous basin, the Budhigandaki River Basin (BRB), in central Nepal. The specific objectives of this research were to: (i) assess the applicability of SWAT model in data scarce and complex mountainous river basin using well-established performance indicators; and (ii) generate spatially distributed flows and evaluate the water balance at the sub-basin level. The BRB was discretised into 16 sub-basins and 344 hydrological response units (HRUs) and calibration and validation was carried out at Arughat using daily flow data of 20 years and 10 years, respectively. Moreover, this study carried out additional validation at three supplementary points at which the study team collected primary river flow data. Four statistical indicators: Nash–Sutcliffe efficiency (NSE), percent bias (PBIAS), ratio of the root mean square error to the standard deviation of measured data (RSR) and Kling Gupta efficiency (KGE) have been used for the model evaluation. Calibration and validation results rank the model performance as “very good”. This study estimated the mean annual flow at BRB outlet to be 240 m3/s and annual precipitation 1528 mm with distinct seasonal variability. Snowmelt contributes 20% of the total flow at the basin outlet during the pre-monsoon and 8% in the post monsoon period. The 90%, 40% and 10% exceedance flows were calculated to be 39, 126 and 453 m3/s respectively. This study provides additional evidence to the SWAT diaspora of its applicability to simulate the rainfall-runoff characteristics of such a complex mountainous catchment. The findings will be useful for hydrologists and planners in general to utilize the available water rationally in the times to come and particularly, to harness the hydroelectric potential of the basin.

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Section: Discussionmentioning

confidence: 99%

Application of SWAT in Hydrological Simulation of Complex Mountainous River Basin (Part I: Model Development)

Marahatta

Devkota

Aryal

2021

Water

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“…Various risk prevention measurements, e.g., siphon system, automatic early warning system, and artificial channel excavation, have been carried out at the Tsho Rolpa [41]. Several studies have predicted the possible response of glaciers and glacial lakes under the climate change in the Tama Koshi basin, provided the management experience and scheme of dangerous glacial lakes and discussed the potential risks of GLOFs [37,40,42,43].…”

Section: Study Areamentioning

confidence: 99%

Rapid glacier Shrinkage and Glacial Lake Expansion of a China-Nepal Transboundary Catchment in the Central Himalayas, between 1964 and 2020

et al. 2021

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Climate warming and concomitant glacier recession in the High Mountain Asia (HMA) have led to widespread development and expansion of glacial lakes, which reserved the freshwater resource, but also may increase risks of glacial lake outburst floods (GLOFs) or debris floods. Using 46 moderate- and high-resolution satellite images, including declassified Keyhole and Landsat missions between 1964 and 2020, we provide a comprehensive area mapping of glaciers and glacial lakes in the Tama Koshi (Rongxer) basin, a highly glacierized China-Nepal transnational catchment in the central Himalayas with high potential risks of glacier-related hazards. Results show that the 329.2 ± 1.9 km2 total area of 271 glaciers in the region has decreased by 26.2 ± 3.2 km2 in the past 56 years. During 2000–2016, remarkable ice mass loss caused the mean glacier surface elevation to decrease with a rate of −0.63 m a−1, and the mean glacier surface velocity slowed by ~25% between 1999 and 2015. The total area of glacial lakes increased by 9.2 ± 0.4 km2 (~180%) from 5.1 ± 0.1 km2 in 1964 to 14.4 ± 0.3 km2 in 2020, while ice-contacted proglacial lakes have a much higher expansion rate (~204%). Large-scale glacial lakes are developed preferentially and experienced rapid expansion on the east side of the basin, suggesting that in addition to climate warming, the glacial geomorphological characters (aspect and slope) are also key controlling factors of the lake growing process. We hypothesize that lake expansion will continue in some cases until critical local topography (i.e., steepening icefall) is reached, but the lake number may not necessarily increase. Further monitoring should be focused on eight rapidly expanding proglacial lakes due to their high potential risks of failure and relatively high lake volumes.

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“…Glaciers are natural water reservoirs 1,2 and are of vital importance to hydropower generation and hydrological models. 3,4 They are important indicators of climate variation [5][6][7] because fluctuations in climate can cause changes in their areal extent, volume, mass balance, [8][9][10] and equilibrium line altitude (ELA). 11 Mass balance and ELA, as direct reflections of climate change, integrate the competing effects of snow accumulation and ablation processes.…”

Section: Introductionmentioning

confidence: 99%

Variability of the snowline altitude in the eastern Tibetan Plateau from 1995 to 2016 using Google Earth Engine

Liu

Zhang

et al. 2021

J. Appl. Rem. Sens.

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The glacier snowline can be used as an indicator of a glacier's equilibrium line, which is a pivotal parameter for studying the effect of climate change on glaciers. However, the relationship between snowline altitudes (SLAs) and climatic regime, as well as the comparison between different glacier types, has received less attention. Using Google Earth Engine, we first developed an automated algorithm that employs the Otsu thresholding method to distinguish snow-covered areas from clean ice on a near-infrared band of Landsat imagery available from 1995 to 2016 and further to delineate glacier SLAs in the three regions of the eastern Tibetan Plateau (TP). The three study regions, Sepu Kangri (maritime), Bu'Gyai Kangri (continental), and western Qiajajima (continental), in the eastern TP have different climate regimes and are on a latitudinal transect from south to north. We then investigated the impacts of climatic factors on the SLA and its variability over the period studied. The results over the eastern TP indicate that (1) the SLA increased by 94, 55, and 49 m from south to north during the 22-year period, with the SLA variations of maritime glaciers being the most pronounced; (2) the southern maritime glaciers were mainly affected by precipitation, whereas the northern continental glaciers were influenced by temperature. Owing to the difference in primary climatic factors affecting snowlines, continental glaciers were found to have higher SLAs on the south slope, whereas maritime glaciers had higher SLAs on the north slope.

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Future projection of cryospheric and hydrologic regimes in Koshi River basin, Central Himalaya, using coupled glacier dynamics and glacio-hydrological models

Cited by 33 publications

References 48 publications

Application of SWAT in Hydrological Simulation of Complex Mountainous River Basin (Part I: Model Development)

Application of SWAT in Hydrological Simulation of Complex Mountainous River Basin (Part I: Model Development)

Rapid glacier Shrinkage and Glacial Lake Expansion of a China-Nepal Transboundary Catchment in the Central Himalayas, between 1964 and 2020

Variability of the snowline altitude in the eastern Tibetan Plateau from 1995 to 2016 using Google Earth Engine

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