From observed impacts to rainfall thresholds: compound risks of urban pluvial flooding
Mobini, Shifteh LU
and Pirzamanbin, Behnaz
LU
(2026)
The Swedish Climate Symposium 2026
- Abstract
- Urban pluvial flooding is a growing climate-related risk in Nordic cities, where short-duration rainfall extremes interact with aging drainage infrastructure and urban form. This study analyses 17 years (2006–2023) of property-level basement flooding reports from Trelleborg, a coastal municipality in southern Sweden, to identify empirical rainfall thresholds and infrastructural conditions associated with flood occurrence and recurrence. Using observational flood report data combined with high-resolution rainfall records, we apply statistical tests and decision-tree models to examine interactions between rainfall intensity, sewer system configuration, and property type.
Results indicate that basement flooding is most strongly associated... (More) - Urban pluvial flooding is a growing climate-related risk in Nordic cities, where short-duration rainfall extremes interact with aging drainage infrastructure and urban form. This study analyses 17 years (2006–2023) of property-level basement flooding reports from Trelleborg, a coastal municipality in southern Sweden, to identify empirical rainfall thresholds and infrastructural conditions associated with flood occurrence and recurrence. Using observational flood report data combined with high-resolution rainfall records, we apply statistical tests and decision-tree models to examine interactions between rainfall intensity, sewer system configuration, and property type.
Results indicate that basement flooding is most strongly associated with 60-minute rainfall intensity rather than total rainfall volume. A critical threshold of approximately 21–23 mm h⁻¹ was consistently identified across analytical methods, with substantial flooding even occurring below the national 10-year design standard. Combined sewer systems showed associations with disproportionately high flood recurrence, but repeated flooding was also observed in separated systems under moderate rainfall, indicating that infrastructure upgrades alone do not eliminate risk. Property type further conditioned recurrence, highlighting compound interactions between hydrometeorological drivers and built-environment characteristics.
The findings highlight how tree-based models identify key split points in rainfall conditions associated with recorded flood incidents, The approach is transferable to other cities seeking empirically grounded benchmarks for climate adaptation and risk management.
Keywords
Urban Pluvial flooding, Empirical rainfall thresholds, compound climate risk (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/18a425d4-7a4d-433b-b193-6fd742fa3a0a
- author
- Mobini, Shifteh
LU
and Pirzamanbin, Behnaz
LU
- organization
- publishing date
- 2026-05-21
- type
- Contribution to conference
- publication status
- unpublished
- subject
- conference name
- The Swedish Climate Symposium 2026
- conference location
- Lund, Sweden
- conference dates
- 2026-05-20 - 2026-05-22
- project
- Digital Transformation of Flood Prediction and Management in Trelleborg
- language
- English
- LU publication?
- yes
- id
- 18a425d4-7a4d-433b-b193-6fd742fa3a0a
- date added to LUP
- 2026-06-04 11:12:57
- date last changed
- 2026-06-08 16:19:17
@misc{18a425d4-7a4d-433b-b193-6fd742fa3a0a,
abstract = {{Urban pluvial flooding is a growing climate-related risk in Nordic cities, where short-duration rainfall extremes interact with aging drainage infrastructure and urban form. This study analyses 17 years (2006–2023) of property-level basement flooding reports from Trelleborg, a coastal municipality in southern Sweden, to identify empirical rainfall thresholds and infrastructural conditions associated with flood occurrence and recurrence. Using observational flood report data combined with high-resolution rainfall records, we apply statistical tests and decision-tree models to examine interactions between rainfall intensity, sewer system configuration, and property type.<br/>Results indicate that basement flooding is most strongly associated with 60-minute rainfall intensity rather than total rainfall volume. A critical threshold of approximately 21–23 mm h⁻¹ was consistently identified across analytical methods, with substantial flooding even occurring below the national 10-year design standard. Combined sewer systems showed associations with disproportionately high flood recurrence, but repeated flooding was also observed in separated systems under moderate rainfall, indicating that infrastructure upgrades alone do not eliminate risk. Property type further conditioned recurrence, highlighting compound interactions between hydrometeorological drivers and built-environment characteristics.<br/>The findings highlight how tree-based models identify key split points in rainfall conditions associated with recorded flood incidents, The approach is transferable to other cities seeking empirically grounded benchmarks for climate adaptation and risk management.<br/>Keywords<br/>Urban Pluvial flooding, Empirical rainfall thresholds, compound climate risk}},
author = {{Mobini, Shifteh and Pirzamanbin, Behnaz}},
language = {{eng}},
month = {{05}},
title = {{From observed impacts to rainfall thresholds: compound risks of urban pluvial flooding}},
year = {{2026}},
}