ALBERT

Description: Past Damaging Hydrogeological Events (DHEs), which can be defined as periods characterised by heavy rainfall inducing such damaging phenomena as landslides and floods, are analysed in this article. The work is focused on the relationships between these phenomena and the characteristics of triggered rainfall, to supply useful suggestions for early detection and damage mitigation. The analysis of past DHEs allows for the characterisation of the main types of DHEs, which affected a selected area in the past and could affect it again in the future. The proposed characterisation is based on triggering scenarios (meteorological conditions preceding the occurrence of DHEs), DHE‘s effects (damage caused by landslides and floods) and triggering factors (rainfall of different durations). Based on these features, the typical DHEs affecting a study area can be outlined and ranked according to their severity, thus specific emergency management can be planned to successfully manage them. To obtain results that have a reliable statistical meaning, a large amount of data of three different types (meteorological, rainfall and damage data) must be treated, and some indices, allowing the comparative analysis of these kinds of data, have to be introduced. In this work we describe the methodological approach, which can be applied in different climatic and anthropogenic contexts;finally, some applications of the proposed method to the region of Calabria (South Italy) are presented

Description: Published

Description: 727-748

Description: N/A or not JCR

Description: restricted

Description: A natural hazard is a geophysical, atmospheric or hydrological event (e.g., earthquake, landslide, tsunami, windstorm, flood or drought) that has the potential to cause harm or loss, while a natural disaster is the occurrence of an extreme hazard event that impacts on communities causing damage, disruption and casualties, and leaving the affected communities unable to function normally without outside assistance (Twig, 2007). The definition of natural disaster impact (NDI) can change according to both the aim of the study and the scientist assessing it. It can be defined as constituting the direct, indirect and intangible losses caused on environment and society by a natural disaster (Swiss Re, 1998). Direct losses include physical effects such as destruction and changes that reduce the functionality of an individual or structure. Damages to people (death/injury), buildings, their contents, and vehicles are included, as are clean-up and disposal costs. Indirect losses affect society by disrupting or damaging utility services and local businesses. Loss of revenue; increase in cost; expenses connected to the provision of assistance, lodging, and drinking water; and costs associated with the need to drive longer distances because of blocked roads are included. Intangible losses include psychological impairments caused by both direct and intangible losses that individuals personally suffer during the disaster. The Natural Disaster Impact Assessment (NDIA) is crucial in helping individuals to estimate replacement costs and to conduct cost-benefit analyses in allotting resources to prevent and mitigate the consequences of damage (UNEP-ECLAC, 2000). A general NDIA procedure has not yet been developed; several approaches are available in literature and their applicability depends on the accessibility of damage data. Possible end users of NDIA include the following (Lindell & Prater, 2003): 1.Governments, with an interest in estimating direct losses to report to taxpayers and to identify segments of the community that have been (or might be) disproportionately affected 2.Community leaders, who may need to use loss data after a disaster strikes to determine if external assistance is necessary and, if so, how much. 3.Planners, who can develop damage predictions to assess the effects of alternative hazard adjustments. Knowing both the expected losses and the extent to which those losses could be reduced makes it possible to implement cost-effective mitigation strategies. 4.Insurers, who need data on the maximum losses in their portfolios to guarantee their solvency or even to undertake additional measures to alleviate the risk that they would face in case of a disaster (i.e., the use of catastrophe bonds which are risk-linked securities that transfer a specified set of risks from a sponsor to investors) (Noy & Nualsri, 2011). Data availability and reliability, especially for old events, represent constraints in the NDIA context because of several issues of very different type: 1.Data availability, for current events, depends on the time at which data gathering started. It is impossible to decide a priori when data have to be gathered: it primarily depends on the type of phenomenon causing the disaster and its magnitude, and secondly on the scope of the assessment (for example, the assessment should not be unnecessarily delayed as there is an urgent need to elicit support from the international community) (ECLAC, 2003). 2.Long-term losses must sometimes be determined over a period of years. Slow landslides, for example, can cause damage over long periods. Intangible damage like disaster-related stress also requires years to be detected (Bland et al., 1996). 3.In most countries, there are no agencies responsible for gathering damage data. Damage caused by severest events can be mined from international databases, while data on less severe events can be obtained by means of specific historical studies. 4.Data on property damage can depreciate the value of property, thus they would not be available or not completely reliable (Highland, 2003). 5.For some type of disasters, as landslides or floods, the costs of damages to structures such as roads are often merged with maintenance costs and are therefore not labelled as damage. In addition, when heavy rains trigger both landslides and floods (Petrucci and Polemio, 2009), it is difficult to separate landslide damage from flood damage. 6.Developing countries have an incentive to exaggerate damage to receive higher amounts of international assistance; thus, in these cases, data may not be entirely reliable (Toya & Skidmore, 2007). This chapter starts with a panoramic of the different approaches reported in the literature to assess the impact of natural disasters, and then presents some simplified approaches to perform a relative and comparative assessment of the impact caused by phenomena as landslides and floods triggered by heavy rainfall during events defined as Damaging Hydrogeological Events. Finally, some indices to assess the relative impact of landslides are presented.

Description: Published

Description: 109-132

Description: open

Description: Risk management has reduced vulnerability to floods and droughts globally, yet their impacts are still increasing. An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data. On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change.

Description: As the adverse impacts of hydrological extremes increase in many regions of the world, a better understanding of the drivers of changes in risk and impacts is essential for effective flood and drought risk management and climate adaptation. However, there is currently a lack of comprehensive, empirical data about the processes, interactions, and feedbacks in complex human-water systems leading to flood and drought impacts. Here we present a benchmark dataset containing socio-hydrological data of paired events, i.e. two floods or two droughts that occurred in the same area. The 45 paired events occurred in 42 different study areas and cover a wide range of socio-economic and hydro-climatic conditions. The dataset is unique in covering both floods and droughts, in the number of cases assessed and in the quantity of socio-hydrological data. The benchmark dataset comprises (1) detailed review-style reports about the events and key processes between the two events of a pair; (2) the key data table containing variables that assess the indicators which characterize management shortcomings, hazard, exposure, vulnerability, and impacts of all events; and (3) a table of the indicators of change that indicate the differences between the first and second event of a pair. The advantages of the dataset are that it enables comparative analyses across all the paired events based on the indicators of change and allows for detailed context- and location-specific assessments based on the extensive data and reports of the individual study areas. The dataset can be used by the scientific community for exploratory data analyses, e.g. focused on causal links between risk management; changes in hazard, exposure and vulnerability; and flood or drought impacts. The data can also be used for the development, calibration, and validation of socio-hydrological models. The dataset is available to the public through the GFZ Data Services (Kreibich et al., 2023, 10.5880/GFZ.4.4.2023.001).

Description: Damaging Hydrogeological Events (DHE) are defined as rainy periods during which landslides and floods can damage people. The paper investigated the effects of DHE on people living in Calabria (southern Italy) in the period 2000–2014, using data coming from the systematic survey of regional newspapers. Data about fatalities, people injured and people involved (not killed neither hurt) were stored in the database named PEOPLE, made of three sections: (1) event identification, (2) victim-event interaction, (3) effects on people. The outcomes highlighted vulnerability factors related to gender and age: males were killed more frequently (75 %) than females (25 %), and fatalities were older (average age 49 years) than injured (40.1 years) and involved people (40.5 years). The average ages of females killed (67.5 years), injured (43.4 years) and involved (44.6 years) were higher than the same values assessed for males, maybe indicating that younger females tended to be more cautious than same-age males, while older females showed an intrinsic greater vulnerability. Involved people were younger than injured people and fatalities, perhaps because younger people show greater promptness to react in dangerous situations. In the study region, floods caused more fatalities (67.9 %), injured (55 %) and involved people (55.3 %) than landslides. Fatalities and injuries mainly occurred outdoor, especially along roads, and the most dangerous dynamic was to be dragged by flood, causing the majority of fatalities (71.4 %). These outcomes can be used to strengthen the strategies aimed at saving people, and to customise warning campaigns according to the local risk features and people's behaviour. The results can improve the understanding of the potential impacts of geo-hydrological hazards on the population and can increase risk awareness among both administrators and citizens.

Description: Calabria (southern Italy) is a flood prone region, due to both its rough orography and fast hydrologic response of most watersheds. During the rainy season, intense rain affects the region, triggering floods and mass movements that cause economic damage and fatalities. This work presents a methodological approach to perform the comparative analysis of two events affecting the same area at a distance of 15 years, by collecting all the qualitative and quantitative features useful to describe both rain and damage. The aim is to understand if similar meteorological events affecting the same area can have different outcomes in terms of damage. The first event occurred between 8 and 10 September 2000, damaged 109 out of 409 municipalities of the region and killed 13 people in a campsite due to a flood. The second event, which occurred between 30 October and 1 November 2015, damaged 79 municipalities, and killed a man due to a flood. The comparative analysis highlights that, despite the exceptionality of triggering daily rain was higher in the 2015 event, the damage caused by the 2000 event to both infrastructures and belongings was higher, and it was strongly increased due to the 13 flood victims. We concluded that, in the 2015 event, the management of pre-event phases, with the issuing of meteorological alert, and the emergency management, with the preventive evacuation of people in hazardous situations due to landslides or floods, contributed to reduce the number of victims.

Description: Floods are still a significant threat to people, despite of the considerable developments in forecasting, management, defensive, and rescue works. In the near future, climate and societal changes as both urbanization of flood prone areas and individual dangerous behaviors could increase flood fatalities. This paper analyzes flood mortality in eight countries using a 39-year database (1980–2018) named EUFF (EUropean Flood Fatalities), which was built using documentary sources. The narratives of fatalities were investigated and standardized in the database reporting the details of the events. The entire dataset shows a stable trend on flood fatalities, despite the existence of individual increasing (Greece, Italy, and South France) and decreasing (Turkey and Catalonia) trends. The 2466 fatalities were mainly males, aged between 30–49 years and the majority of them happened outdoor. Most often people were dragged by water/mud when travelling by motor vehicles. Some cases of hazardous behaviors, such as fording rivers, were also detected. The primary cause of death was drowning, followed by heart attack. This work contributes to understand the human–flood interaction that caused fatalities. The changes in society’s vulnerability highlighted throughout this study contribute to manage future risks, to improve people protection actions, and to reduce risk behaviors.