Yesterday’s extremes, today’s new normal: flood risk in the Kathmandu Valley, Nepal

Journal Article · Wed Aug 13 00:00:00 EDT 2025 · Natural Hazards

DOI:https://doi.org/10.1007/s11069-025-07524-5· OSTI ID:2583774

Talchabhadel, Rocky ^[1]; Panthi, Jeeban ^[2]; Pandey, Vishnu P. ^[3]; Rakhal, Biplob ^[4]; Ghimire, Ganesh R. ^[5]; Bista, Sunil ^[1]; Bhattarai, Saurav ^[1]; Poudel, Subash ^[1]; Bhattarai, Yogesh ^[6]; Prajapati, Rajaram ^[7]; Thapa, Bhesh R. ^[8]; Nepal, Bikash ^[9]; Sharma, Sanjib ^[6]

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1. Jackson State Univ., Jackson, MS (United States)
2. Kansas State Univ., Manhattan, KS (United States)
3. Tribhuvan Univ., Kirtipur (Nepal)
4. World Food Programme (Nepal)
5. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
6. Howard Univ., Washington, DC (United States)
7. Univ. of Pittsburgh, PA (United States)
8. Pokhara Univ. (Nepal)
9. Government of Nepal (Nepal); Chinese Academy of Sciences (CAS), Beijing (China); University of Chinese Academy of Sciences, Beijing (China)

Unplanned urban growth has left many cities increasingly vulnerable to extreme rainfall events, particularly in regions with inadequate drainage infrastructures and development encroaching on natural floodplains. Here, in this perspective paper, we examine the September 2024 floods that struck Central Nepal, triggered by a persistent low-pressure system and enhanced by converging moisture flows from the Arabian Sea and the Bay of Bengal which led to widespread catastrophic damage. In the Kathmandu Valley, floodwaters expanded to more than 2.5 times the bankfull water extent, causing significant damage to housing, transportation network, and critical infrastructure, displacing thousands of residents, and severely disrupting urban services. This event highlights the urgent need for improved flood management strategies that integrate both structural and non-structural measures into the infrastructure development. While early warning systems provided critical lead time, challenges remain in reducing forecasting uncertainties and improving communication across government agencies and with local communities. A forward-looking approach is essential, including probabilistic flood forecasting systems, sustainable floodplain management, risk-sensitive land use planning, climate- and disaster- resilient infrastructure development, and the integration of nature-based solutions like urban green and blue spaces to mitigate flood impacts. By involving local communities in planning and preparedness efforts, particularly through citizen science initiatives, and engagement with underserved and disadvantaged communities, Nepal can better adapt to the growing risks posed by extreme rainfall and urban flooding and enhance long-term disaster resilience in rapidly urbanizing areas like Kathmandu Valley.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 2583774
• Journal Information: Natural Hazards, Journal Name: Natural Hazards Journal Issue: 16 Vol. 121; ISSN 1573-0840; ISSN 0921-030X
• Publisher: Springer Nature
• Country of Publication: United States
• Language: English

Related Subjects

Kathmandu Valley
extreme weather
flood risk management
urbanization
vulnerability