Contribution of Baseflow to River Streamflow: Study on Nepal’s Bagmati and Koshi Basins

Bastola, Satish; Seong, Yeonjeong; Lee, Daeeop; Youn, Ilro; Oh, Se‐Wook; Jung, Younghun; Choi, Gye-Woon; Jang, Dongwoo

doi:10.1007/s12205-018-0149-9

Cited by 13 publications

(11 citation statements)

References 19 publications

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“…The highest BFI appeared from August to October, and the lowest BFI values were from April to June. Bastola et al [51] found that the minimum value of monthly average BFIs was in June, and the maximum BFIs were in October to November in the Koshi and Bagmati Basin in Nepal, which suggested the opposite to baseflow variations, as noted in the current study. The BFIs values from the four methods in the St. Johns (0308) subregion (southern area) are shown in Figure 11.…”

Section: Resultssupporting

confidence: 67%

Comparative Analysis of Four Baseflow Separation Methods in the South Atlantic-Gulf Region of the U.S.

Chen

Teegavarapu

2019

Water

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Baseflow estimation and evaluation are two critical and essential tasks for water quality and quantity, drought management, water supply, and groundwater protection. Observed baseflows are rarely available and are limited to focused pilot studies. In this study, an exhaustive evaluation of four different baseflow separation methods (HYSEP, WHAT, BFLOW, and PART) using surrogates of observed baseflows estimated with the conductivity mass balance (CMB) method is carried out using data from several streamflow gauging sites from the South Atlantic-Gulf (SAG) region comprised of nine states in the Southeastern U.S. Daily discharge data from 75 streamflow gauging sites for the period 1970–2013, located in the least anthropogenically affected basins in the SAG region were used to estimate the baseflow index (BFI), which quantifies the contribution of baseflow from streamflows. The focus of this study is to compare the four different baseflow separation methods and calibrate and validate these methods using CMB method based estimates of baseflows to evaluate the variation of BFI values derived from these methods. Results from the study suggest that the PART and HYSEP methods provide the highest and lowest average BFI values of 0.62 and 0.52, respectively. Similarities in BFI values estimated from these methods are noted based on a strong correlation between WHAT and BFLOW. The highest BFI values were found in April in the eastern, western, and central parts of the SAG region, and the highest contribution of baseflow to the streamflow was noted in October in the southern region. However, the lowest BFI values were noted in the month of September in all regions of SAG. The calibrated WHAT method using data from the CMB method provides the highest correlation as noted by the coefficient of determination. This study documents an exhaustive and comprehensive evaluation of baseflow separation methods in the SAG region, and results from this work can aid in the selection of the best method based on different metrics reported in this study. The use of the best method can aid in the short and long term management of low flows at a regional level that supports a sustainable aquatic environment and mitigates the effects of droughts effectively.

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Section: Resultssupporting

confidence: 67%

Comparative Analysis of Four Baseflow Separation Methods in the South Atlantic-Gulf Region of the U.S.

Chen

Teegavarapu

2019

Water

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“…As the baseflow cannot be directly observed, foreign researchers have proposed various baseflow splitting methods, such as the direct splitting method, water balance method, numerical simulation method and hydrological modeling method, based on the difference in confluence between the steep rise and fall of surface runoff and the slow rise and fall of subsurface runoff. Among them, the direct splitting method is highly subjective, workload and not suitable for long time-scale baseflow splitting; the water balance method has more parameters, complex formulas and difficult to optimize; the hydrological modeling method has clear physical meaning and high credibility, but requires more parameters and extremely complex operation; and the numerical simulation method is highly efficient, repeatable and widely used in current research (Hao et al 2019), mainly including the digital filtering method (Hamidreza & Keith 2015), the hydrograph separation program (HYSEP) (Gardner et al 2010) and the minimum smoothing method (Bastola et al 2018).…”

Section: Methodology Base Flow Segmentationmentioning

confidence: 99%

Method to identify composition and production phases of spring runoff in high-latitude mid-temperate regions: a case study in the Second Songhua River Basin, China

Yangzong

Yang

et al. 2021

Journal of Water and Climate Change

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Simulation and forecast of runoff play an important role in the early warning and prevention of drought and flood disasters. To improve the accuracy of spring runoff simulations, it is important to identify spring runoff production patterns under the combined effect of snow and frozen soil. Based on the theory of the hydrological cycle, three important parameters, which include surface and subsurface runoff, precipitation and temperature, were selected for this study. The trend analysis, statistical analysis and Eckhardt's recursive numerical filtering method were used to qualitatively identify the production patterns of spring runoff, the start and end dates and stage periods of the production patterns. Based on the qualitative identification results, the contribution of each production runoff to the total annual runoff and the total annual spring runoff is quantitatively assessed. The results of the study show that the spring runoff production patterns in the Second Songhua River Basin can be divided into snowmelt runoff, frozen soil conditions of snowmelt–rainfall runoff and rainfall runoff under frozen soil conditions; the snowmelt production is from 21 March, the frozen soil conditions production is from 21 April and the frozen soil ablation is ended on 15 June; the phases of each production pattern are the shortest lasting 28, 20 and 18 days and the longest lasting 31, 26 and 24 days. This research is providing the basis for improving the principles of production runoff calculation in spring runoff simulation methods.

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“…17 The baseflow is >45% of streamflow in all seasons and is sustained by glacier runoff and groundwater in the nonmonsoon season (October−May). 14,18,19 A transient (∼45 days) groundwater storage is released into the Kosi River during the postmonsoon season (i.e., October−November). 17 Water cations are dominated by Ca 2+ and Mg 2+ , suggesting carbonate weathering as one of the main geochemical processes in this region.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…The annual discharge is estimated to be ∼47 km 3 yr –1 into the Ganga (Sun Kosi, Arun, and Tamor discharges are ∼56, 38, and 16%, respectively). , Glaciers cover ∼4–15% of the upper part of the catchment . The baseflow is >45% of streamflow in all seasons and is sustained by glacier runoff and groundwater in the nonmonsoon season (October–May). ,, A transient (∼45 days) groundwater storage is released into the Kosi River during the postmonsoon season (i.e., October–November) . Water cations are dominated by Ca 2+ and Mg 2+ , suggesting carbonate weathering as one of the main geochemical processes in this region. , Straddling the Indo-Nepal border, the Kosi Barrage was completed in 1963 for purposes of irrigation, hydropower generation, flood control, etc.…”

Section: Methodsmentioning

confidence: 99%

Characteristics of Dissolved Organic Matter from a Transboundary Himalayan Watershed: Relationships with Land Use, Elevation, and Hydrology

Chen

Zeng

Zhang

et al. 2020

ACS Earth Space Chem.

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Himalayan rivers play pivotal roles in regional water and food supplies, global sediments, and carbon budgets. We studied a transboundary mountainous Kosi River in the Himalayas by utilizing ultraviolet–visible spectroscopy and excitation–emission matrix coupled with parallel factor analysis. We have found that agricultural land use promoted the production of abundant proteinlike fluorescence in the surface waters [∼1.1–1.8 Raman unit (RU) for two proteinlike components that accounts for ≥97% of relative abundance] as opposed to natural vegetation land cover (e.g., forests and grasslands), despite the low dissolved organic carbon (DOC, 0.50–1.02 mg L–1), implying more reactive fluorescent dissolved organic matter (FDOM) that can potentially cause more CO2 outgassing. Furthermore, we observed a decreasing trend of slope ratio (S R) and proteinlike fluorescence with elevation as opposed to a humiclike component, potentially due to more concentrated croplands and consequent nutrient inputs to rivers at lower elevations. In addition, poststorm samples shifted to more humiclike FDOM and chromophoric DOM (CDOM) sides compared to baseflow water. These findings highlighted the importance of land uses and other environmental conditions, such as elevation and hydrology, on DOM characteristics and dynamics and water quality, which can potentially be amplified due to the steep gradients in mountainous watersheds. Measures should be taken for proper and sustainable land uses to mitigate river water eutrophication and pollution and to protect drinking water sources for millions of populations.

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Contribution of Baseflow to River Streamflow: Study on Nepal’s Bagmati and Koshi Basins

Cited by 13 publications

References 19 publications

Comparative Analysis of Four Baseflow Separation Methods in the South Atlantic-Gulf Region of the U.S.

Comparative Analysis of Four Baseflow Separation Methods in the South Atlantic-Gulf Region of the U.S.

Method to identify composition and production phases of spring runoff in high-latitude mid-temperate regions: a case study in the Second Songhua River Basin, China

Characteristics of Dissolved Organic Matter from a Transboundary Himalayan Watershed: Relationships with Land Use, Elevation, and Hydrology

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