Flash flood occurrence and relation to the rainfall hazard in a highly urbanized area
The paper examines the flash flood events that occurred over a decade in the Attica prefecture, the most urbanized region of Greece, with the aim of identifying triggering rainfall thresholds, as well as assessing the effect of rainfall upon the magnitude of the induced damages. The analysis incorpo...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-08-01
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| Series: | Natural Hazards and Earth System Sciences |
| Online Access: | http://www.nat-hazards-earth-syst-sci.net/15/1859/2015/nhess-15-1859-2015.pdf |
| Summary: | The paper examines the flash flood events that occurred over a decade in
the Attica prefecture, the most urbanized region of Greece, with the aim of
identifying triggering rainfall thresholds, as well as assessing the effect
of rainfall upon the magnitude of the induced damages. The analysis
incorporates rainfall records from a network of 28 surface meteorological
stations and information on the spatial distribution of the flash flood
events that is derived from the active database of damaging weather events
maintained by the atmospheric modelling group of the National Observatory of
Athens. The main findings concern firstly the relation between the flash
flood impact, as measured by the fire service operations in flooded
properties, and precipitation in various time intervals. In the period
2005–2014, 48 damaging flash flood events occurred in the target area and
caused more than 3500 fire service operations in flooded properties. Most
of the events are associated with maximum accumulated rainfall of more than 20 mm
in 24 h and 3 mm in 10 min. However, the flash flood impact
intensity, as measured by the number of the fire service operations per
event, increases significantly above the levels of 60 mm in 24 h and 10 mm in
10 min. Secondly, graphs of rainfall intensity versus duration are
developed for 15 sub-areas of Attica in order to define rainfall intensity
thresholds for flood triggering at a more local level. It is shown that
conclusions regarding the reliability of the estimated thresholds should
take into account the representativity of the rain gauges, which is
determined by the local network's density, the gauges' location and record
length. |
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| ISSN: | 1561-8633 1684-9981 |