The presence of moral hazard regarding flood insurance and German private businesses

Natural Hazards - There is a movement towards the concepts of integrated flood risk management and governance. In these concepts, each stakeholder prone to flooding is tasked with actively limiting...     

Flexible–inflexible: socio-demographic,spatial and temporal dimensions of flat sharing in Leipzig (Germany)

Flat sharers are one of the most distinct representatives of the ‘new’ household types, but have received only very limited attention from researchers. Back in the 1960s shared flats were usually founded with a strong ideological impetus, whereas flat sharing nowadays is just one household type among many others. Typically, this housing arrangement consists of at least two young adult individuals without children. Sharing the flat and the housing costs is the basis of their relationship but living with others is an additional motive. As a rule, flat sharing bridges two distinct events in the course of one’s life: the leaving of the parental home and the foundation of the first independent household. Thus for a restricted period in time, it is a flexible household type adapted to the situational needs of its members. Germany has one of the strongest and longest traditions of flat sharing in Europe, especially among university students. An explorative study was conducted in Leipzig to come to a deeper understanding of what flat sharing means in its ambivalence of being both an economic unit and a social arrangement. Based on qualitative and quantitative evidence from group discussions and Internet adverts, we shed light on the highly under-researched social practice of flat sharing. We will show that despite the structural flexibility of this household type, there is also evidence for its socio-demographic selectivity, spatial concentration and temporal limitation over the individual life courses.     

Biotic drivers of river and floodplain geomorphology – New molecular methods for assessing present‐day and past biota

Geomorphology has increasingly considered the role of biotic factors as controls upon geomorphic processes across a wide range of spatial and temporal scales. Where timescales are long (centennial and longer), it has been possible to quantify relationships between geomorphic processes and vegetation using, for example, the pollen record. However, where the biotic agents are fauna, longer term reconstruction of the impacts of biological activity upon geomorphic processes is more challenging. Here, we review the prospect of using environmental DNA as a molecular proxy to decipher the presence and nature of faunal influences on geomorphic processes in both present and ancient deposits. When used appropriately, this method has the potential to improve our understanding of biotic drivers of geomorphic processes, notably fauna, over long timescales and so to reconstruct how such drivers might explain the landscape as we see it today. Copyright © 2017 John Wiley & Sons, Ltd.     

Development of FLEMOcs – a new model for the estimation of flood losses in the commercial sector

Abstract

The estimation of flood damage is an important component for risk-oriented flood design, risk mapping, financial appraisals and comparative risk analyses. However, research on flood-loss modelling, especially in the commercial sector, has not gained much attention so far. Therefore, extensive data about flood losses were collected for affected companies via telephone surveys after the floods of 2002, 2005 and 2006 in Germany. Potential loss determining factors were analysed. The new Flood Loss Estimation MOdel for the commercial sector (FLEMOcs) was developed on the basis of 642 loss cases. Losses are estimated depending on water depth, sector and company size as well as precaution and contamination. The model can be applied to the micro-scale, i.e. to single production sites as well as to the meso-scale, i.e. land-use units, thus enabling its countrywide application.

Citation Kreibich, H., Seifert, I., Merz, B. & Thieken, A. H. (2010) Development of FLEMOcs – a new model for the estimation of flood losses in the commercial sector. Hydrol. Sci. J. 55(8), 1302–1314.     

Application and validation of FLEMOcs – a flood-loss estimation model for the commercial sector

Abstract

The estimation of flood loss is difficult, especially in the commercial sector, because of its great inhomogeneity. However, the reliability of loss modelling is fairly unknown, since flood-loss models are scarcely validated. The newly developed Flood Loss Estimation MOdel for the commercial sector (FLEMOcs) was validated on the micro-scale using a leave-one-out cross-validation procedure. Additionally, different meso-scale loss functions were compared. Meso-scale model application was undertaken in 19 municipalities which were affected during the 2002 flood in Germany. Model results were compared with the results of three other loss models, as well as with official loss records. The micro-scale validation shows very good results, with no bias and mean absolute errors between 23 and 31%. The meso-scale validation indicates that FLEMOcs provides good results, especially in large areas with many affected companies where high losses are expected.

Citation Seifert, I., Kreibich, H., Merz, B. & Thieken, A. H. (2010) Application and validation of FLEMOcs – a flood-loss estimation model for the commercial sector. Hydrol. Sci. J. 55(8), 1315–1324.     

Spatio-temporal dynamics in the flood exposure due to land use changes in the Alpine Lech Valley in Tyrol (Austria)

Flood risk is expected to increase in many regions of the world in the next decades with rising flood losses as a consequence. First and foremost, it can be attributed to the expansion of settlement and industrial areas into flood plains and the resulting accumulation of assets. For a future-oriented and a more robust flood risk management, it is therefore of importance not only to estimate potential impacts of climate change on the flood hazard, but also to analyze the spatio-temporal dynamics of flood exposure due to land use changes. In this study, carried out in the Alpine Lech Valley in Tyrol (Austria), various land use scenarios until 2030 were developed by means of a spatially explicit land use model, national spatial planning scenarios and current spatial policies. The combination of the simulated land use patterns with different inundation scenarios enabled us to derive statements about possible future changes in flood-exposed built-up areas. The results indicate that the potential assets at risk depend very much on the selected socioeconomic scenario. The important conditions affecting the potential assets at risk that differ between the scenarios are the demand for new built-up areas as well as on the types of conversions allowed to provide the necessary areas at certain locations. The range of potential changes in flood-exposed residential areas varies from no further change in the most moderate scenario ‘Overall Risk’ to 119 % increase in the most extreme scenario ‘Overall Growth’ (under current spatial policy) and 159 % increase when disregarding current building restrictions.     

Flood risk curves and uncertainty bounds

The Scotia Arc is one of two regions in the Atlantic Ocean with greater potential for tsunami generation from seismic and volcanic sources. A numerical modeling study was undertaken to determine tsunami generation from postulated sources along the Arc and tsunami wave amplification or attenuation along the Patagonian continental shelf. Sea level oscillation represented by a simple sinusoidal wave function applied at the boundary of the numerical grid, which simulated the tsunami entering the computational domain, was implemented as forcing. The validation of this model was carried out by comparing the maximum amplitudes recorded and simulated at Santa Teresita and Mar del Plata (Buenos Aires province) after the occurrence of earthquake and subsequent tsunami in Sumatra (December 2004). From numerical simulations it can be seen that the tsunami propagation is highly affected by bathymetric refraction on the Patagonian continental shelf and the wave amplitude is significantly attenuated on the inner continental shelf. Maximum amplifications were obtained around Malvinas (Falkland) Islands and Burdwood bank because the wave propagates almost without refracting and the shoaling effect is highly significant there.     

Coping with floods in the city of Dresden,Germany

During August 2002 and again in March 2005 as well as in April 2006 the city of Dresden was hit by floods. The flood in 2002 was an extreme event, only comparable to flooding in 1862 and 1890 in Dresden. The flood discharge in 2006 was the second highest discharge since 1940 at the Dresden gauge although its return period was only about 15 years. This special situation enables a comparison of the preparedness of authorities and households in the flood endangered city of Dresden in 2002 after a long period of relatively low flood discharges and in 2005/2006 just a few years after a severe flood event. Before August 2002, the flood risk awareness and flood preparedness of authorities and households in Dresden was low. The inundation channels and the Elbe riverbed had not been maintained well. Just 13% of the households had undertaken building precautionary measures. The severe flood situation as well as the low flood preparedness led to tremendous damage, e.g., losses to residential buildings amounted to 304 million €. After 2002, the municipal authorities in Dresden developed a new flood management concept and many households were motivated to undertake precautionary measures. Building precautionary measures had been actually undertaken by 67% of the households before the floods in 2005 and 2006. Flood damage was significantly lower, due to the less severe flood situations and the much better preparedness. It is an important challenge for the future to keep preparedness at a high level also without recurrent flood experiences.