Evaluation of post extreme floods in high mountain region: A case study of the Melamchi flood 2021 at the Koshi River Basin in Nepal
Extreme precipitation events and associated hazards are becoming more frequent and intense due to climate change. On June 2021, a devastating flash flood occurred in the Melamchi River in Nepal causing immense destruction to lives and property. The flood event was cascading in nature and associated...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
KeAi Communications Co. Ltd.
2023-09-01
|
| Series: | Natural Hazards Research |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666592123000707 |
| _version_ | 1797615941905809408 |
|---|---|
| author | Tirtha Raj Adhikari Binod Baniya Qiuhong Tang Rocky Talchabhadel Manish Raj Gouli Bhumi Raj Budhathoki Ram Prasad Awasthi |
| author_facet | Tirtha Raj Adhikari Binod Baniya Qiuhong Tang Rocky Talchabhadel Manish Raj Gouli Bhumi Raj Budhathoki Ram Prasad Awasthi |
| author_sort | Tirtha Raj Adhikari |
| collection | DOAJ |
| description | Extreme precipitation events and associated hazards are becoming more frequent and intense due to climate change. On June 2021, a devastating flash flood occurred in the Melamchi River in Nepal causing immense destruction to lives and property. The flood event was cascading in nature and associated with multiple driving factors. This study evaluates the post-extreme flood conditions of the Melamchi Flood 2021 (MF21). Rainfall, streamflow (discharge), and gauge height (water level) data of the nearest stations were analyzed. Since there was a lack of reliable instantaneous river discharge during the disastrous MF21, this study developed the flow rating curves at hydrometric stations. Post-extreme flood was evaluated considering upstream catchment hydrology, glacial lake outbursts, landslide damming, and the hydrodynamic propagations using the Hydrologic Engineering Center's River Analysis System (HEC-RAS) model and gauge-to-gauge (G2G) correlation. The results were then compared to field observations. The HEC-RAS model was simulated for several flood frequency periods in different return periods (namely 2, 5, 10, 25, 50, 100, 200, 500, and 1000 years). Results showed that the average 24 h gauge height and discharge at Nakote station (a few km downstream of landslide damming) are 15.88 m and 169.18 m3/s, in which the model-based highest frequency of 1-h extreme flood and return period can reach 716 m3/s in 1000 years. During MF21, the discharge of the Nakote region at the 10 min intervals was estimated to be with a maximum of 7162.10 m3/s, an average of 2207.13 m3/s and a minimum of 237.44 m3/s.Additionally, the outburst discharge from glacial lake at high elevation was estimated to be 295.14 m3/s contributing to downstream flooding. The model-based discharge during the past flood period was also estimated in 9 cross-section points of the river in which discharge at the damming area was 63.81 m3/s and downstream Dumredovan was 1206.58 m3/s. This research provides valuable insights to post-extreme flood evaluation and the approach can be used for other watersheds in evaluating post flood conditions. |
| first_indexed | 2024-03-11T07:33:10Z |
| format | Article |
| id | doaj.art-a51939a7a5764490aea732c6329ccb88 |
| institution | Directory Open Access Journal |
| issn | 2666-5921 |
| language | English |
| last_indexed | 2024-03-11T07:33:10Z |
| publishDate | 2023-09-01 |
| publisher | KeAi Communications Co. Ltd. |
| record_format | Article |
| series | Natural Hazards Research |
| spelling | doaj.art-a51939a7a5764490aea732c6329ccb882023-11-17T05:28:18ZengKeAi Communications Co. Ltd.Natural Hazards Research2666-59212023-09-0133437446Evaluation of post extreme floods in high mountain region: A case study of the Melamchi flood 2021 at the Koshi River Basin in NepalTirtha Raj Adhikari0Binod Baniya1Qiuhong Tang2Rocky Talchabhadel3Manish Raj Gouli4Bhumi Raj Budhathoki5Ram Prasad Awasthi6Central Department of Hydrology and Meteorology, Tribhuvan University, Kirtipur, Kathmandu, Nepal; College of Applied Science, Tribhuvan University, NepalDepartment of Environmental Science, Patan Multiple Campus, Tribhuvan University, Nepal; Corresponding author.Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, ChinaTexas A&M AgriLife Research, Texas A&M University, El Paso, TX, USAInstitute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, ChinaCentral Department of Hydrology and Meteorology, Tribhuvan University, Kirtipur, Kathmandu, NepalDepartment of Hydrology and Meteorology, Government of Nepal, NepalExtreme precipitation events and associated hazards are becoming more frequent and intense due to climate change. On June 2021, a devastating flash flood occurred in the Melamchi River in Nepal causing immense destruction to lives and property. The flood event was cascading in nature and associated with multiple driving factors. This study evaluates the post-extreme flood conditions of the Melamchi Flood 2021 (MF21). Rainfall, streamflow (discharge), and gauge height (water level) data of the nearest stations were analyzed. Since there was a lack of reliable instantaneous river discharge during the disastrous MF21, this study developed the flow rating curves at hydrometric stations. Post-extreme flood was evaluated considering upstream catchment hydrology, glacial lake outbursts, landslide damming, and the hydrodynamic propagations using the Hydrologic Engineering Center's River Analysis System (HEC-RAS) model and gauge-to-gauge (G2G) correlation. The results were then compared to field observations. The HEC-RAS model was simulated for several flood frequency periods in different return periods (namely 2, 5, 10, 25, 50, 100, 200, 500, and 1000 years). Results showed that the average 24 h gauge height and discharge at Nakote station (a few km downstream of landslide damming) are 15.88 m and 169.18 m3/s, in which the model-based highest frequency of 1-h extreme flood and return period can reach 716 m3/s in 1000 years. During MF21, the discharge of the Nakote region at the 10 min intervals was estimated to be with a maximum of 7162.10 m3/s, an average of 2207.13 m3/s and a minimum of 237.44 m3/s.Additionally, the outburst discharge from glacial lake at high elevation was estimated to be 295.14 m3/s contributing to downstream flooding. The model-based discharge during the past flood period was also estimated in 9 cross-section points of the river in which discharge at the damming area was 63.81 m3/s and downstream Dumredovan was 1206.58 m3/s. This research provides valuable insights to post-extreme flood evaluation and the approach can be used for other watersheds in evaluating post flood conditions.http://www.sciencedirect.com/science/article/pii/S2666592123000707Extreme floodClimate changeHEC-RASMelamchi watershedNepal |
| spellingShingle | Tirtha Raj Adhikari Binod Baniya Qiuhong Tang Rocky Talchabhadel Manish Raj Gouli Bhumi Raj Budhathoki Ram Prasad Awasthi Evaluation of post extreme floods in high mountain region: A case study of the Melamchi flood 2021 at the Koshi River Basin in Nepal Natural Hazards Research Extreme flood Climate change HEC-RAS Melamchi watershed Nepal |
| title | Evaluation of post extreme floods in high mountain region: A case study of the Melamchi flood 2021 at the Koshi River Basin in Nepal |
| title_full | Evaluation of post extreme floods in high mountain region: A case study of the Melamchi flood 2021 at the Koshi River Basin in Nepal |
| title_fullStr | Evaluation of post extreme floods in high mountain region: A case study of the Melamchi flood 2021 at the Koshi River Basin in Nepal |
| title_full_unstemmed | Evaluation of post extreme floods in high mountain region: A case study of the Melamchi flood 2021 at the Koshi River Basin in Nepal |
| title_short | Evaluation of post extreme floods in high mountain region: A case study of the Melamchi flood 2021 at the Koshi River Basin in Nepal |
| title_sort | evaluation of post extreme floods in high mountain region a case study of the melamchi flood 2021 at the koshi river basin in nepal |
| topic | Extreme flood Climate change HEC-RAS Melamchi watershed Nepal |
| url | http://www.sciencedirect.com/science/article/pii/S2666592123000707 |
| work_keys_str_mv | AT tirtharajadhikari evaluationofpostextremefloodsinhighmountainregionacasestudyofthemelamchiflood2021atthekoshiriverbasininnepal AT binodbaniya evaluationofpostextremefloodsinhighmountainregionacasestudyofthemelamchiflood2021atthekoshiriverbasininnepal AT qiuhongtang evaluationofpostextremefloodsinhighmountainregionacasestudyofthemelamchiflood2021atthekoshiriverbasininnepal AT rockytalchabhadel evaluationofpostextremefloodsinhighmountainregionacasestudyofthemelamchiflood2021atthekoshiriverbasininnepal AT manishrajgouli evaluationofpostextremefloodsinhighmountainregionacasestudyofthemelamchiflood2021atthekoshiriverbasininnepal AT bhumirajbudhathoki evaluationofpostextremefloodsinhighmountainregionacasestudyofthemelamchiflood2021atthekoshiriverbasininnepal AT ramprasadawasthi evaluationofpostextremefloodsinhighmountainregionacasestudyofthemelamchiflood2021atthekoshiriverbasininnepal |