A spatial multicriteria prioritizing approach for geo-hydrological risk mitigation planning in small and densely urbanized Mediterranean basins
<p>Landslides and floods, particularly flash floods, occurred recently in many Mediterranean catchments as a consequence of heavy rainfall events, causing damage and sometimes casualties. The high hazard is often associated with high vulnerability deriving from intense urbanization, in particu...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-01-01
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| Series: | Natural Hazards and Earth System Sciences |
| Online Access: | https://www.nat-hazards-earth-syst-sci.net/19/53/2019/nhess-19-53-2019.pdf |
| Summary: | <p>Landslides and floods, particularly flash floods, occurred recently in many
Mediterranean catchments as a consequence of heavy rainfall events, causing
damage and sometimes casualties. The high hazard is often associated with
high vulnerability deriving from intense urbanization, in particular along
the coastline where streams are habitually culverted. The necessary risk
mitigation strategies should be applied at the catchment scale with a holistic
approach, avoiding spot interventions.</p>
<p>In the present work, a high-risk area, hit in the past by several floods and
concurrent superficial landslides due to extremely localized and intense
rain events, has been studied. A total of 21 small catchments have been identified:
only some of them have been hit by extremely damaging past events, but all
lie in the intense-rain high-hazard area and are strongly urbanized in the
lower coastal zone. The question is what would happen if an intense rain
event should strike one of the not previously hit catchments; some situations
could be worse or not, so attention has been focused on the comparison
among catchments. The aim of the research has been identifying a priority
scale among catchments, pointing out the more critical ones and giving a
quantitative comparison tool for decision makers to support strong
scheduling of long-time planning interventions at the catchment scale. The past
events' effects and the geomorphic process analysis together with the field
survey allowed us to select three sets of parameters: one describing the
morphometric–morphological features related to flood and landslide hazard,
another describing the degree of urbanization and of anthropogenic
modifications at the catchment scale and the last related to the elements that
are exposed to risk. The realized geodatabase allowed us to apply the spatial
multicriteria analysis technique (S-MCA) to the descriptive parameters and
to obtain a priority scale among the analyzed catchments. The scale can be
used to plan risk mitigation interventions starting from the more critical
catchments, then focusing economic resources primarily on them and obtaining
an effective prevention strategy. The methodology could be useful even to
check how the priority scale is modified during the progress of the
mitigation work realization.</p>
<p>In addition, this approach could be applied in a similar context, even among
sub-catchments, after identifying a suitable set of descriptive parameters
depending on the active geomorphological processes and the kind of
anthropogenic modification. The prioritization would allow to invest
economic resources in risk mitigation interventions priory in the more
critical catchments.</p> |
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| ISSN: | 1561-8633 1684-9981 |