Pluvial, urban flood mechanisms and characteristics – Assessment based on insurance claims

Sörensen, Johanna; Mobini, Shifteh (2017-12-01). Pluvial, urban flood mechanisms and characteristics – Assessment based on insurance claims. Journal of Hydrology, 555,, 51 - 67
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DOI:
| Published | English
Authors:
Sörensen, Johanna ; Mobini, Shifteh
Department:
Division of Water Resources Engineering
Project:
Just or Unjust - Assessment of rainfall-related flood damage in a Swedish context
Sustainable Urban Flood Management
Urban flooding in a changing climate
Abstract:

Pluvial flooding is a problem in many cities and for city planning purpose the mechanisms behind pluvial flooding are of interest. Previous studies seldom use insurance claim data to analyse city scale characteristics that lead to flooding. In the present study, two long time series (∼20 years) of flood claims from property owners have been collected and analysed in detail to investigate the mechanisms and characteristics leading to urban flooding. The flood claim data come from the municipal water utility company and property owners with insurance that covers property loss from overland flooding, groundwater intrusion through basement walls and flooding from the drainage system. These data are used as a proxy for flood severity for several events in the Swedish city of Malmö. It is discussed which rainfall characteristics give most flooding and why some rainfall events do not lead to severe flooding, how city scale topography and sewerage system type influence spatial distribution of flood claims, and which impact high sea level has on flooding in Malmö. Three severe flood events are described in detail and compared with a number of smaller flood events. It was found that the main mechanisms and characteristics of flood extent and its spatial distribution in Malmö are intensity and spatial distribution of rainfall, distance to the main sewer system as well as overland flow paths, and type of drainage system, while high sea level has little impact on the flood extent. Finally, measures that could be taken to lower the flood risk in Malmö, and other cities with similar characteristics, are discussed.

Keywords:
Extreme precipitation ; Flood mechanisms ; Insurance claims ; Pluvial flooding ; Urban flooding
ISSN:
0022-1694
LUP-ID:
e4f2ba6a-7653-4f3b-8d03-9775846e9de4 | Link: https://lup.lub.lu.se/record/e4f2ba6a-7653-4f3b-8d03-9775846e9de4 | Statistics

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