Articles | Volume 387
https://doi.org/10.5194/piahs-387-17-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/piahs-387-17-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
A hybrid approach to enhance streamflow simulation in data-constrained Himalayan basins: combining the Glacio-hydrological Degree-day Model and recurrent neural networks
Dinesh Joshi
CORRESPONDING AUTHOR
Department of Environmental Science and Engineering, School of Science, Kathmandu University, Dhulikhel, 45210, Nepal
Rijan Bhakta Kayastha
Department of Environmental Science and Engineering, School of Science, Kathmandu University, Dhulikhel, 45210, Nepal
Kundan Lal Shrestha
Department of Chemical Science and Engineering, School of Engineering, Kathmandu University, Dhulikhel, 45210, Nepal
Rakesh Kayastha
Department of Environmental Science and Engineering, School of Science, Kathmandu University, Dhulikhel, 45210, Nepal
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Javed Hassan, Karina Nielsen, William Colgan, Rijan Bhakta Kayastha, Mira Khadka, and Shfaqat Abbas Khan
EGUsphere, https://doi.org/10.5194/egusphere-2026-808, https://doi.org/10.5194/egusphere-2026-808, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
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High-altitude lakes in High Mountain Asia (HMA) are important sources of freshwater and sensitive indicators of environmental change. Using satellite data from 2010 to 2024, we examine water level changes in 232 lakes across HMA. Results show rising lake levels on the Tibetan Plateau, while lakes in the Himalaya are declining. These contrasting patterns highlight strong regional differences and provide valuable information for understanding water availability and associated hazards.
Oscar Paul, N. Nithila Devi, Rakesh Teja Konduru, Soumendra Nath Kuiry, Kundan Lal Shrestha, and Chandan Sarangi
EGUsphere, https://doi.org/10.5194/egusphere-2026-1218, https://doi.org/10.5194/egusphere-2026-1218, 2026
This preprint is open for discussion and under review for Natural Hazards and Earth System Sciences (NHESS).
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Despite computationally intensive high-resolution weather models, accurate spatio-temporal rainfall simulation at complex urban scales remains challenging. Using the December 2015 Chennai 1-in-100-year flood as a case study, we show that explicit aerosol representation significantly influences rainfall simulations, improving flood extent mapping by up to 50 %. Our approach resolves urban-scale aerosol microphysics and can be systematically extended to other extreme events across regions.
Koji Fujita and Rijan B. Kayastha
EGUsphere, https://doi.org/10.5194/egusphere-2026-1078, https://doi.org/10.5194/egusphere-2026-1078, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
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Glacier AX010 in Nepal, monitored since the 1970s, has been shrinking at an accelerating rate, mainly due to rising temperatures. Drone surveys, modeling, and reanalysis data show mass loss began in the early 1970s and intensified after 2000. While rising temperatures drive shrinkage, precipitation changes have neither accelerated nor mitigated mass loss. At the current rate, the glacier may disappear within 10–20 years.
Sujan Thapa, Ragini Vaidya, Mohan Bahadur Chand, and Rijan Bhakta Kayastha
EGUsphere, https://doi.org/10.5194/egusphere-2025-4454, https://doi.org/10.5194/egusphere-2025-4454, 2025
Preprint archived
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This study examines how avalanches striking a glacial lake can cause sudden floods downstream in Nepal's Manaslu region. We used computer simulations to simulate various avalanche sizes and their effects on the lake. These simulations revealed that medium and large avalanches could lead to severe flooding in a short amount of time. This highlights the pressing need for early warning systems and better disaster preparedness to protect at-risk communities.
Kundan Lal Shrestha, Rijan Bhakta Kayastha, and Rakesh Kayastha
Proc. IAHS, 387, 25–31, https://doi.org/10.5194/piahs-387-25-2024, https://doi.org/10.5194/piahs-387-25-2024, 2024
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The Himalayan river basins have complex terrain and lack detailed hydrological and meteorological information. This has motivated us to develop a fast and distributed model named PyGDM to simulate the hydrology of this region, which is home to both glaciers and snow. PyGDM is good at simulating glacier and snow melt. Hence, the model is suitable for studying different aspects of the Himalayan region, such as the impact of climate change and hydropower scenarios.
Rakesh Kayastha, Rijan Bhakta Kayastha, Kundan Lal Shrestha, and Smriti Gurung
Proc. IAHS, 387, 53–58, https://doi.org/10.5194/piahs-387-53-2024, https://doi.org/10.5194/piahs-387-53-2024, 2024
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We have estimated hydropower potential in the two glacierized river basins of the Nepalese Himalayas. The Glacio-hydrological Degree-Day Model (GDM) was used with different geospatial criteria. In order to force the model simulation and to assess potential future hydrological regimes, a variety of climate variables were combined and used. The sensitivity of climate variables and their impact on hydropower potential were investigated with a combination of different climate variables.
Rijan Bhakta Kayastha and Sunwi Maskey
Proc. IAHS, 387, 59–63, https://doi.org/10.5194/piahs-387-59-2024, https://doi.org/10.5194/piahs-387-59-2024, 2024
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Glacial lake outburst flood (GLOF) modeling of Tsho Rolpa showed that, even if the lake breaches by 20 m in 40 years (from 2021), there will be a sufficient lead time of more than 7 h for early warning and human evacuations in the downstream areas. However, precautionary measures such as community-based GLOF early-warning systems and mechanisms allowing close observation in the case of GLOF events should be established in GLOF-prone regions.
Rijan Bhakta Kayastha, Hari Krishna Shrestha, and Dhiraj Pradhananga
Proc. IAHS, 387, 1–2, https://doi.org/10.5194/piahs-387-1-2024, https://doi.org/10.5194/piahs-387-1-2024, 2024
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Short summary
This study explores the potential of integrating data science models to enhance the predictive capacity of a theory-guided glacier hydrological model for improved river discharge simulations in the Himalayan basins. By combining data science and physical process models, the study addresses the limitations inherent in each approach.
This study explores the potential of integrating data science models to enhance the predictive...
Special issue