Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Mudd, Simon M. and Attal, Mikael and Borthwick, Alistair and Ghimire, Bhola N. and Scott Watson, C. (2024) The impact of sediment flux and calibre on flood risk in the Kathmandu Valley, Nepal. Earth Surface Processes and Landforms, 49 (2). pp. 706-727. ISSN 0197-9337
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This paper investigates how variations in sediment supply, grain size distribution and climate change affect channel morphology and flood inundation in the Nakkhu River. The study uses a landscape evolution model to simulate potential erosion and deposition scenarios along a 14 km reach of the river.AI Topics:
This paper investigates how variations in sediment supply, grain size distribution and climate change affect channel morphology and flood inundation in the Nakkhu River, Kathmandu, Nepal. Climate change-induced extreme rainfall is expected to increase flood intensity and frequency, causing severe flooding in the Kathmandu basin. The upper reaches of the Nakkhu River are susceptible to landslides and have been impacted by large-scale sand mining. We simulate potential erosion and deposition scenarios along a 14 km reach of the Nakkhu River using the landscape evolution model CAESAR-Lisflood with a 10 m digital elevation model, field-derived sediment grain size data, daily discharge records and flood forecast models. In a series of numerical experiments, we compare riverbed profiles, cross-sections, flood extent and flow depths for three scenarios (1.2-, 85- and 1000-year return period floods). For each scenario, the model is first run without sediment transport and then with sediment transport for three grain size distributions (GSDs) (observed average, finer and coarser). In all cases, the inclusion of sediment led to predicted floods of a larger extent than estimated without sediment. The sediment grain size distribution was found to have a significant influence on predicted river morphology and flood inundation, especially for lower magnitude, higher probability flood events. The results emphasise the importance of including sediment transport in hydrological models when predicting flood inundation in sediment-rich rivers such as those in and around the Himalaya.
Thapa, Saraswati
Author
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Borthwick, Alistair and Watson, C. Scott and Muthusamy, Manoranjan (2024) Sediment transport and flood risk: impact of newly constructed embankments on river morphology and flood dynamics in Kathmandu, Nepal. Water Resources Research, 60 (10): e2024WR037. ISSN 1944-7973
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Mudd, Simon M. and Attal, Mikael and Borthwick, Alistair and Ghimire, Bhola N. and Scott Watson, C. (2024) The impact of sediment flux and calibre on flood risk in the Kathmandu Valley, Nepal. Earth Surface Processes and Landforms, 49 (2). pp. 706-727. ISSN 0197-9337
See full publications listSinclair, Hugh D.
Author
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Borthwick, Alistair and Watson, C. Scott and Muthusamy, Manoranjan (2024) Sediment transport and flood risk: impact of newly constructed embankments on river morphology and flood dynamics in Kathmandu, Nepal. Water Resources Research, 60 (10): e2024WR037. ISSN 1944-7973
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Mudd, Simon M. and Attal, Mikael and Borthwick, Alistair and Ghimire, Bhola N. and Scott Watson, C. (2024) The impact of sediment flux and calibre on flood risk in the Kathmandu Valley, Nepal. Earth Surface Processes and Landforms, 49 (2). pp. 706-727. ISSN 0197-9337
Shrestha, Dibesh and Basnyat, Divas B. and Gyawali, Januka and Creed, Maggie J. and Sinclair, Hugh D. and Golding, Brian and Muthusamy, Manoranjan and Shrestha, Shankar and Scott Watson, C. and Subedi, Divya L. and Haiju, Rojina (2023) Rainfall extremes under future climate change with implications for urban flood risk in Kathmandu, Nepal. International Journal of Disaster Risk Reduction, 97: 103997. ISSN 2212-4209
See full publications listCreed, Maggie
Author
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Borthwick, Alistair and Watson, C. Scott and Muthusamy, Manoranjan (2024) Sediment transport and flood risk: impact of newly constructed embankments on river morphology and flood dynamics in Kathmandu, Nepal. Water Resources Research, 60 (10): e2024WR037. ISSN 1944-7973
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Mudd, Simon M. and Attal, Mikael and Borthwick, Alistair and Ghimire, Bhola N. and Scott Watson, C. (2024) The impact of sediment flux and calibre on flood risk in the Kathmandu Valley, Nepal. Earth Surface Processes and Landforms, 49 (2). pp. 706-727. ISSN 0197-9337
Scott Watson, C. and Gyawali, Januka and Creed, Maggie and Elliott, John R. (2024) City-scale high-resolution flood models and the role of topographic data: a case study of Kathmandu, Nepal. Geocarto International, 39 (1): 2387073. ISSN 1010-6049
See full publications listMudd, Simon M.
Author
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Mudd, Simon M. and Attal, Mikael and Borthwick, Alistair and Ghimire, Bhola N. and Scott Watson, C. (2024) The impact of sediment flux and calibre on flood risk in the Kathmandu Valley, Nepal. Earth Surface Processes and Landforms, 49 (2). pp. 706-727. ISSN 0197-9337
See full publications listAttal, Mikael
Author
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Mudd, Simon M. and Attal, Mikael and Borthwick, Alistair and Ghimire, Bhola N. and Scott Watson, C. (2024) The impact of sediment flux and calibre on flood risk in the Kathmandu Valley, Nepal. Earth Surface Processes and Landforms, 49 (2). pp. 706-727. ISSN 0197-9337
See full publications listBorthwick, Alistair
Author
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Borthwick, Alistair and Watson, C. Scott and Muthusamy, Manoranjan (2024) Sediment transport and flood risk: impact of newly constructed embankments on river morphology and flood dynamics in Kathmandu, Nepal. Water Resources Research, 60 (10): e2024WR037. ISSN 1944-7973
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Mudd, Simon M. and Attal, Mikael and Borthwick, Alistair and Ghimire, Bhola N. and Scott Watson, C. (2024) The impact of sediment flux and calibre on flood risk in the Kathmandu Valley, Nepal. Earth Surface Processes and Landforms, 49 (2). pp. 706-727. ISSN 0197-9337
See full publications listGhimire, Bhola N.
Author
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Mudd, Simon M. and Attal, Mikael and Borthwick, Alistair and Ghimire, Bhola N. and Scott Watson, C. (2024) The impact of sediment flux and calibre on flood risk in the Kathmandu Valley, Nepal. Earth Surface Processes and Landforms, 49 (2). pp. 706-727. ISSN 0197-9337
See full publications listScott Watson, C.
Author
Thapa, Saraswati and Sinclair, Hugh D. and Creed, Maggie J. and Mudd, Simon M. and Attal, Mikael and Borthwick, Alistair and Ghimire, Bhola N. and Scott Watson, C. (2024) The impact of sediment flux and calibre on flood risk in the Kathmandu Valley, Nepal. Earth Surface Processes and Landforms, 49 (2). pp. 706-727. ISSN 0197-9337
Scott Watson, C. and Gyawali, Januka and Creed, Maggie and Elliott, John R. (2024) City-scale high-resolution flood models and the role of topographic data: a case study of Kathmandu, Nepal. Geocarto International, 39 (1): 2387073. ISSN 1010-6049
Shrestha, Dibesh and Basnyat, Divas B. and Gyawali, Januka and Creed, Maggie J. and Sinclair, Hugh D. and Golding, Brian and Muthusamy, Manoranjan and Shrestha, Shankar and Scott Watson, C. and Subedi, Divya L. and Haiju, Rojina (2023) Rainfall extremes under future climate change with implications for urban flood risk in Kathmandu, Nepal. International Journal of Disaster Risk Reduction, 97: 103997. ISSN 2212-4209
See full publications listAvailable under License Creative Commons Attribution.
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