River floods Germany
Germany: Vulnerabilities – Flood probability trends in the past
The German territory is comprised of five large river basins (the Elbe, upper Danube, Rhine, Weser and Ems), three medium-scale basins in the coastal area (Eider, Schlei/Trave and Warnow/Peene), and small parts of the Oder and Meuse basins. Of the large river basins, only the Ems and Weser basins lie entirely within the borders of Germany. The Rhine, upper Danube and Elbe are international rivers and their drainage basins have large parts outside Germany.
Overall, it can be summarized that the flood hazard in Germany increased during the last five decades, particularly due to an increased flood frequency. Changes in the flood behavior in northeast Germany are small. Most changes were detected for sites in the west, south and centre of Germany. Further, the seasonal analysis revealed larger changes for winter compared to summer (32).
From an analysis of data for the period 1951-2002 covering the entire country (the catchments of the Danube, the Rhine, the Elbe, the Weser, the Ems, and the Odra), significant flood trends (at the 10% significance level) have been detected for a considerable fraction of basins. In most cases, these trends are upward; decreasing flood trends are rarely found and are not field-significant (32). Changes in flood behavior in northeast Germany are small. Most changes are detected for sites in the west, south and centre of Germany. Further, the seasonal analysis reveals larger changes for winter compared to summer. Both, the spatial and seasonal coherence of the results and the missing relation between significant changes and basin area, suggest that the observed changes in flood behavior are climate-driven (32).
During the last 500 years winter flood hazard in the Werra catchment (sub-catchment of the Weser) showed an increase during the last decades, whereas the summer flood hazard showed a long-term decrease from 1760 on (38). Upward trends in annual maximum flood in the Rhine and Weser basins, found for the period 1951-2002, can be attributed to trends in the winter season, since the flood regime is dominated by winter floods (32).
Elbe and Odra
The Elbe, Danube and Odra catchments are characterized by a relatively small influence of westerly, northwesterly and southwesterly circulation types, a larger share of high pressure systems, and the occurrence of Vb-weather regimes. The Vb-weather regime is a trough over Central Europe, which can bring long-lasting heavy rainfalls causing destructive floods in these catchments (42).
This weather regime moves low pressure systems from the Gulf of Genoa northwards to Poland. Large precipitation amounts can be accumulated and may be enhanced along the northern slopes of the Alps and the mountain ranges in Central and Eastern Europe. Several destructive floods were triggered by this circulation type, as experienced for instance in the Elbe and Danube catchments in 2002 and 2005 (42).
For the Elbe and middle Odra significant downward trends in the occurrence rates of winter floods and no significant trends for summer floods have been found during the 20th century. Moreover, significant variations have been found of occurrence rates for heavy floods during the past centuries and notable differences between Elbe and Odra (39). The reduction in winter flood occurrence for these rivers can partly be attributed to fewer events of strong freezing; following such events, breaking river ice at the end of the winter may function as a water barrier and enhance floods severely. In both rivers, the last ice flood occurred in 1947 (54). Reduced freezing may have been caused by warming (55) or increased pollution of river waters. Elevated winter temperatures could also have had an effect via a reduction of occurrence of frozen soil, which has low absorbing capacity (56). According to data for the period 1951-2002, changes in the flood behavior in northeast Germany are small (32).
Although winter floods dominate in the Elbe, Odra and northern Danube catchments, summer floods can reach remarkable discharges as experienced in 1997, 2002, 2005 (37).
The Rhine and Weser catchments are dominated by westerly, northwesterly and southwesterly circulation types with associated mid-latitude cyclone rainfall (36). Significant upward flood trends in magnitude as well as frequency have been found in the Rhine catchment at the gauges Cologne (1900 – 2002) and Bonn (20). Upward trends in annual maximum flood in the Rhine and Weser basins, found for the period 1951-2002, can be attributed to trends in the winter season, since the flood regime is dominated by winter floods (32).
Between the periods 1901-1930 and 1971-200, the flood discharge, defined as the arithmetic average of the highest daily discharge during these periods, indicates an increase by about + 10 % at most gauging stations along the Rhine. This is not due to an increase of extreme peak flows but due to frequent moderate and great floods. At some gauging stations, however, the development of flood discharge shows a different, and sometimes opposite, trend (60).
Long time series of 70-150 years of 158 gauges in southern Germany mostly revealed no trends. However, the study of the last 30 years showed significant upward trends of annual maximum flood at many gauges. Moreover, the frequency of winter floods increased since the 1970s in many basins (41).
The southern part of the Danube catchment is dominated high pressure systems, especially during fall and winter. Westerly, northwesterly and southwesterly circulation types are less frequent. In this region, summer floods dominate (12). An increasing frequency of winter floods is supposed to be caused by higher winter temperatures, and hence, earlier snow melting in the mountain ranges (32).
A plausible cause of the observed increase in the frequency of flood events (e.g. in southwest Germany (27) is, among others, the statistically evident increasing frequency of extreme rainfall events (28). However, this increase can only be substantiated for the winter months. Therefore, it is believed that the probability of winter floods, such as e.g. the Rhine floods, has already increased.
Summer floods, such as e.g. the floods at the Oder 1997 and the Elbe 2002, are often caused by specific general weather situation (e.g. the socalled “Vb weather condition”). Again, a number of studies substantiate at least the increased frequency of such weather conditions (29).
Flood probability and circulation patterns
So far, the relationship between peak discharges and atmospheric variables has been investigated for Germany only for selected regions. For the Rhine catchment, for instance, increasing trends have been found in wet circulation patterns, areal precipitation and discharge for the period 1951–2000. An even higher significance level of increasing trends was found for winter maximum discharges compared to increasing trends in annual maximum discharges (44).
For the scale of Europe, a trend (significant at 10% SL) towards a reduced diversity of circulation patterns has been found, causing fewer patterns with longer persistence to dominate the weather over Europe. This indicates changes in the dynamics of atmospheric circulations which are of direct relevance to the flood hazard. Longer persistence of circulation patterns may lead to consecutive precipitation events. Although the single events may have rather low precipitation amounts, the succession of several events may lead to saturated catchment conditions. This is particularly important for winter peak discharge, which are in many cases triggered patterns with westerly winds (43).
These results on changes in circulation patterns have implications for flood risk management, especially for flood design measures. A flood frequency analysis approach in which no trend in the data are assumed may underestimate discharges of extreme events (43).
Germany: Vulnerabilities - Non-climatic factors
In the past, extreme rainfall events have repeatedly led to flood disasters involving great damage (Rhine 1993/1994, 1995, Oder 1997 and Danube and Elbe 2002). In addition to climate influences, other factors that play an important role in the risk of flooding are reduced retention due to straightening of watercourses, the construction of weirs, the loss of water meadows and wetlands, and increased surface sealing (21,24).
For example, the river Rhine has already lost four-fifth of its natural floodplains. Similarly, at the river Elbe only 15% of the natural floodplains remain (30). Moreover, agriculture causes more frequent floods by the usage of heavy machinery on arable fields and the consequent condensation of soils, which hampers the infiltration capacity. At present, the influence of these anthropogenic factors is more pronounced than climate change (21).
Although the Rhine catchment has experienced widespread land use changes, significant effects on flooding could only be detected in small basins. There is no evidence for the impact of land use changes on the flood discharge of the Rhine river itself (32). These findings are in line with different studies, which found little or no influence of land use on flood discharge (33).
It has been argued that the impact of land use changes on floods is a matter of spatial scale (34). In small basins land use changes can significantly alter the runoff processes, effecting flood magnitude and frequency. However, these effects are expected to fade with increasing basin scale. The general tendency of decreasing impacts with increasing basin scale does not apply to river training works. On the contrary, river training impacts are likely to increase with catchment size as there is a tendency for larger settlements and hence large-scale flood protection works at larger streams (34).
The cumulative effects of river training works on floods in large basins are difficult to assess (32). Averaged across many flood events, the river training works along the Rhine have increased the flood peaks at Cologne, whereas the retention measures have decreased the peaks. Today’s flood peaks at Cologne are expected to be a few percent higher than before the extensive river training works in the 1950s (35).
Germany: Vulnerabilities - The floods of 2002, 2005 and 2013
The Elbe flood catastrophe of 2002 has not been attributed to climate change in the public’s opinion (22). There is no evidence from flood observations over the last 80-150 years for recent upward trends in the occurrence rate of the extreme floods (return periods of 100 yr and more) that occurred in central Europe in July 1997 (Oder) and August 2002 (Elbe) (54).
The Elbe floods alone claimed 20 lives and caused damage totaling more than EUR 9 billion (24).
In 2005 floods caused a lot of damage and several casualties in the Alpine region. In southern Germany especially the river Lech, flowing from Austria through southern Germany into the Danube, caused large-scale flooding. Locally, 1/300-years water levels were reached (48).
In spring 2013, heavy precipitation in Central Europe resulted in large scale floods along the Elbe and Danube. An observation-based analysis and model simulations show no evidence that climate change made heavy precipitation in the upper Danube and Elbe basins in May–June, such as observed in 2013, more likely (61). These results agree with conclusions of analyses of historical floods on the Elbe (54) and Danube (62) that no change in summer floods can be observed (yet).
Germany: Vulnerabilities – Future projections
Among the potential negative impacts of climate change, the increased risk of flooding and the decrease in water supply during summer are of primary importance. These impacts are the result of an observed shift of precipitation from summer to winter, as well as higher evaporation owing to increased temperature. This shift is expected to become more pronounced in the future. Additionally, the probability of extreme rainfall events is increasing particularly in winter and the duration of snow cover is projected to decrease (21,23).
Presumably, across Germany the risk of flooding increases mostly in the months of winter and spring. The Alpine region and highly built-up regions without sufficient retention areas are particularly at risk. It is as yet unclear to what extent the risk of summer floods will increase (21).
Due to the small changes in annual precipitation under most scenarios, changes in annual runoff in Germany lie below 10%. The regional distribution is however different. In the north and northeast of Germany there appears to be a trend of decreasing runoff, while there is a trend of slightly increasing runoff in the south (21). The uncertainty in projected changes in river floods for German rivers is large however; different models sometimes project different trends (increase/decrease) for a specific river (59,66).
Flood and drought conditions in five large river basins in Germany (covering 90 % of the German territory) were estimated from a large number of (regional climate) model projections (based on several models and the A1B emission scenario of moderate climate change) (66). The results for 2061–2100 (compared with 1961–2000) show that many German rivers may experience higher 50-year floods with a moderate agreement by 60–70 % of projections. The results show very large differences between the projected changes for different model projections, however. The uncertainty of the extreme event projections is too large to identify the robust change signals for most German rivers. Robust changing signals agreed by more than 80 % of projections include an increasing trend of floods in the Elbe basin in 2061–2100. Besides, wetter conditions with higher risk of floods are projected for the rivers flowing from the Alps (particularly the Inn River) in the near future (2021–2060) (66).
Some peak runoff situations could be eased by lack of melt water resulting from reduced accumulation of snow (24,31). Furthermore, decreased frequency of the freezing up of rivers due to temperature increase reduces the probability of floods triggered by ice accumulation, such as have been primarily observed at the Elbe river in the past (26).
Flood events in large watersheds are mostly caused by long-lasting, advective rainfall events (land rain), with or without contributions of snow melting. On the other hand, convective extreme rainfall events (local extreme rainfall events) often cause small-scale floods with high damage potential. Such small-scale floods cause approximately half of all flood damages in Germany (26).
Economic flood losses under climate change
For individual German river reaches, the impact of climate change on flood damages was quantified for the time horizons 2041–2070 and 2071–2100, and compared with the reference period 1961–2000 (63). In this study no changes in land use (e.g., riverine settlements), water management (e.g., flood protection), and value of assets were considered. The future projections were made with regional climate models under a number of climate change scenarios (IPCC SRES scenarios A1B, A2 and B1). The climate scenarios were transformed into river flow and flood frequency characteristics using a hydrological model, and subsequently the projected river flows were transformed into economic losses using damage functions. According to these results (63), the total annual flood damages in Germany sum up to nearly EUR 500 million per year for the reference period 1961–2000 and, on average, double until the end of the scenario period (2071-2100). In fact, total economic losses can be higher than the damages on buildings and small enterprises considered in this study.The projected increase of flood losses is in line with the ones according to other studies for the European scale (64) and for the Rhine basin (65), although the other studies applied different scenario data.
Recently, a thorough study has been carried out into the change of the discharge of the River Rhine during the 21st century. It was concluded that average discharge during summer and winter half-year will increase in 2021-2050 with respect to 1961-1990. At the end of the century (2071-2100) average half-year discharge is projected to increase in the winter and decrease in the summer. High winter discharge is projected to increase both in 2021-2050 and 2071-2100 with respect to 1961-1990 (49).
For the period 2021 - 2050 compared with 1961-1990, flood discharge is projected to increase downstream of the Kaub gauging station, by of -5% to + 15% (“frequent” floods: 10 years recurrence interval), 0% to + 20% (“mean” floods: 100 years recurrence interval) and -5% to +25% (“extreme” floods: 1000 years recurrence interval), respectively. Due to deficits in methods, no statements could be made for the upstream stations Basel, Maxau and Worms (60).
At the end of the 21st century compared with 1961-1990, flood discharge is generally projected to increase downstream of the Kaub gauging station, up to + 30 %. However, some projections also indicate opposite developments, so that, partly, considerable ranges of variation results (Trier: -20% to +45%). Again, due to deficits in methods, no statements could be made for the upstream stations Basel, Maxau and Worms (60).
Europe: casualties in the past
The annual number of reported flood disasters in Europe increased considerably in 1973-2002 (1). A disaster was defined here as causing the death of at least ten people, or affecting seriously at least 100 people, or requiring immediate emergency assistance. The total number of reported victims was 2626 during the whole period, the most deadly floods occurred in Spain in 1973 (272 victims), in Italy in 1998 (147 victims) and in Russia in 1993 (125 victims) (2).
Throughout the 20th century as a whole flood-related deaths have been either stable or decreasing while economic burdens of flooding and related societal disruptions have become decidedly worse. 20th century flood disaster death tolls have been typically averaging fewer than 250 per year (3).
Europe: flood losses in the past
The reported damages also increased. Three countries had damages in excess of €10 billion (Italy, Spain, Germany), three in excess of 5 billion (United Kingdom, Poland, France) (2).
Expressed in 2006 US$ normalised values, total flood losses over the 1970–2006 period amounted to 140 billion, with an average annual flood loss of 3.8 billion (4). Results show no detectable sign of human-induced climate change in normalised flood losses in Europe. There is evidence that societal change and economic development are the principal factors responsible for the increasing losses from natural disasters to date (5).
Policy makers should not expect an unequivocal answer to questions concerning the linkage between flood-disaster losses and anthropogenic climate change, as this field will very likely remain an important area of research for years to come. Longer time-series of losses are necessary for more conclusive results (6).
Europe: flood frequency trends in the past
In 2012 the IPCC concluded that there is limited to medium evidence available to assess climate-driven observed changes in the magnitude and frequency of floods at a regional scale because the available instrumental records of floods at gauge stations are limited in space and time, and because of confounding effects of changes in land use and engineering. Furthermore, there is low agreement in this evidence, and thus overall low confidence at the global scale regarding even the sign of these changes. There is low confidence (due to limited evidence) that anthropogenic climate change has affected the magnitude or frequency of floods, though it has detectably influenced several components of the hydrological cycle such as precipitation and snowmelt (medium confidence to high confidence), which may impact flood trends (57).
Despite the considerable rise in the number of reported major flood events and economic losses caused by floods in Europe over recent decades, no significant general climate‑related trend in extreme high river flows that induce floods has yet been detected (7).
Hydrological data series do not indicate clear upward trends in the frequency and magnitude of floods in Europe. The direct anthropogenic causes include land use change, river channel modifications and increased activities in areas vulnerable to floods. Thousands of square kilometres of impermeable surfaces have been created, coastal urbanization has been extensive. The overall impact of these changes probably exceeds the impact of trends in meteorological variables in today's Europe (8).
In western and central Europe, annual and monthly mean river flow series appear to have been stationary over the 20th century (9). In mountainous regions of central Europe, however, the main identified trends are an increase in annual river flow due to increases in winter, spring and autumn river flow. In southern parts of Europe, a slightly decreasing trend in annual river flow has been observed (10).
In the Nordic countries, snowmelt floods have occurred earlier because of warmer winters (11). In Portugal, changed precipitation patterns have resulted in larger and more frequent floods during autumn but a decline in the number of floods in winter and spring (12). Comparisons of historic climate variability with flood records suggest, however, that many of the changes observed in recent decades could have resulted from natural climatic variation. Changes in the terrestrial system, such as urbanisation, deforestation, loss of natural floodplain storage, as well as river and flood management have also strongly affected flood occurrence (13).
Europe: projections for the future
In 2012 the IPCC concluded that considerable uncertainty remains in the projections of flood changes, especially regarding their magnitude and frequency. They concluded, therefore, that there is low confidence (due to limited evidence) in future changes in flood magnitude and frequency derived from river discharge simulations. Projected precipitation and temperature changes imply possible changes in floods, although overall there is low confidence in projections of changes in fluvial floods. Confidence is low due to limited evidence and because the causes of regional changes are complex, although there are exceptions to this statement. There is medium confidence (based on physical reasoning) that projected increases in heavy rainfall would contribute to increases in rain-generated local flooding, in some catchments or regions. Earlier spring peak flows in snowmelt- and glacier-fed rivers are very likely, but there is low confidence in their projected magnitude (57).
More frequent flash floods
Although there is as yet no proof that the extreme flood events of recent years are a direct consequence of climate change, they may give an indication of what can be expected: the frequency and intensity of floods in large parts of Europe is projected to increase (14). In particular, flash and urban floods, triggered by local intense precipitation events, are likely to be more frequent throughout Europe (15).
More frequent floods in the winter
Flood hazard will also probably increase during wetter and warmer winters, with more frequent rain and less frequent snow (16). Even in regions where mean river flows will drop significantly, as in the Iberian Peninsula, the projected increase in precipitation intensity and variability may cause more floods.
Reduction spring snowmelt floods
In snow‑dominated regions such as the Alps, the Carpathian Mountains and northern parts of Europe, spring snowmelt floods are projected to decrease due to a shorter snow season and less snow accumulation in warmer winters (17). Earlier snowmelt and reduced summer precipitation will reduce river flows in summer (18), when demand is typically highest.
For the period 2071-2100 the general feature is a decrease of extreme flows in areas where snowmelt floods are dominating in the present climate. The hundred year floods will attenuate by 10-50% in northern Russia, Finland and most mountainous catchments throughout Europe. An increase by similar amount is projected in large areas elsewhere, whereas a mixed pattern is likely in Sweden, Germany and the Iberian Peninsula (2).
Increase flood losses
Losses from river flood disasters in Europe have worsened in recent years and climate change is expected to exacerbate this trend. The PESETA study, for example, estimates that by the 2080s, some 250-400 million Europeans could be affected each year (compared with 200 million in the period between 1961 and 1990). At the same time, annual losses due to river flooding in Europe could rise to €8-15 billion by the end of the century compared with an average of €6 billion today (51).
From an assessment of the implications of climate change for future flood damage and people exposed by floods in Europe it was concluded that the expected annual damages (EAD) and expected annual population exposed (EAP) will see an increase in several countries in Europe in the coming century (58). Most notable increases in flood losses across the different climate futures are projected for countries in Western Europe (Belgium, Denmark, France, Germany, Ireland, Luxembourg, the Netherlands and the United Kingdom), as well as for Hungary and Slovakia. A consistent decrease across the scenarios is projected for northern countries (Estonia, Finland, Latvia, Lithuania and Sweden). For EU27 as a whole, current EAD of approximately €6.4 billion is projected to at least double or triple by the end of this century (in today’s prices), depending on the scenario. Changes in EAP reflect well the changes in EAD, and for EU27 an additional 250,000 to nearly 400,000 people are expected to be affected by flooding yearly, depending on the scenario. The authors stress that the monetary estimates of flood damage are uncertain because of several assumptions underlying the calculations (only two emission scenarios, only two regional climate models driven by two general circulation models, no discounting of inflation to future damages, no growth in exposed values and population or adjustments, estimates of flood protection standards); the results are indicative of changes in flood damage due to climate change, however, rather than estimates of absolute values of flood damage (58).
Large differences across Europe
Annual river flow is projected to decrease in southern and south-eastern Europe and increase in northern and north-eastern Europe (19).
Strong changes are also projected in the seasonality of river flows, with large differences across Europe. Winter and spring river flows are projected to increase in most parts of Europe, except for the most southern and south-eastern regions. In summer and autumn, river flows are projected to decrease in most of Europe, except for northern and north-eastern regions where autumn flows are projected to increase (20). Predicted reductions in summer flow are greatest for southern and south-eastern Europe, in line with the predicted increase in the frequency and severity of drought in this region.
Climate-related changes in flood frequency are complex and dependent on the flood generating mechanism (e.g. heavy rainfall vs spring snowmelt), affected in different ways by climate change. Hence, in the regions where floods can be caused by several possible mechanisms, the net effect of climate change on flood risk is not trivial and a general and ubiquitously valid, flat-rate statement on change in flood risk cannot be made (52).
Flood risk tends to increase over many areas owing to a range of climatic and non-climatic impacts, whose relative importance is site-specific. Flood risk is controlled by a number of non-climatic factors, such as changes in economic and social systems, and in terrestrial systems (hydrological systems and ecosystems). Land-use changes, which induce land-cover changes, control the rainfall-runoff relations in the drainage basin. Deforestation, urbanization and reduction of wetlands diminish the available water-storage capacity and increase the runoff coefficient, leading to growth in the flow amplitude and reduction of the time-to-peak. Furthermore, in many regions, people have been encroaching into, and developing, flood-prone areas, thereby increasing the damage potential. Important factors of relevance to flood risk are population and economy growth, flood protection strategy, flood risk awareness (or flood risk ignorance) behaviour and a compensation culture (52).
Adaptation strategies - Infrastructural measures
The probable increase in flood frequency and the possible increase in runoff need to be taken into account in the adaptation to future climate conditions. To do this, present measures of flood protection need to be adapted. This includes sufficient flood retention on floodplains, a regulation that limits construction and other development on the likely floodplains, precaution in constructions, behavioural foresight, hazard protection and technical flood protection (21,24).
In a survey of experts, most of the flood control measures were regarded as already partially introduced, though preventive building was still at the planning stage and technical flood control was almost completely implemented (25). There are however great differences in implementation between the individual states of Germany. These are partly due to regional differences in the flood risk (24). Significant efforts have already been taken to lower the risks of flooding since the Elbe flood catastrophe of 2002 (22).
There is a need for further implementation of flood prevention measures such as improvements in short-term forecasts of high and low water, the designation of flood areas, and implementation of hydraulic engineering and maintenance measures in a manner that has a neutral impact on flooding and takes account of environmental criteria (24).
To ensure that there is more space for water so that it causes less damage, as many flood areas as possible
should be designated by the year 2020. The basic guide for spatial planning should be the risk of the type of extreme flooding which occurs statistically on average every 200 years. Improved drainage through decentralised rainwater soak-away facilities, renaturing of rivers and lakes, reforestation and adapted agriculture promote localised retention of water and increase groundwater recharge at the same time. (53).
Dyke retrenchment measures, restoration of floodplain forests and reconnection of old river arms are regarded by experts as effective flood control measures for rivers. By 2006 these measures were regarded as partially implemented. Restrictions on use in flood areas, such as restrictions on new building and on handling substances dangerous to water – e.g. non-use of oil-fired heating systems – are already regulated by law (24).
So far, the water sector is little adapted to the impacts of climate change. In the planning of flood protection the impacts of climate change find little consideration in most federal states. Therefore, the vulnerability of the water sector is considered as “high” across Germany (21).
Bayern has implemented a number of measures for flood protection between now and 2020 (Hochwasserschutz-Aktionsprogramm 2020) for a total of 2.3 Billion Euros, including (46):
- measures to renaturalise the river landscape, and thus increase the retention and discharge capacity of rivers and streams;
- infrastructural measures to protect the area against 1/100-years floods;
- measures to reduce the damage by floods (spatial planning, building regulations, reliable flood warnings) and to insure the damage.
In the Alps programs are started to improve flood protection facilities like dams, create floodplains, and keep areas with high risks for flooding clear from housing and constructions (47).
Flood risk reduction via land-use planning
Zoning policies can be used to limit the exposure to flooding of people and assets. Zoning regulations entail the determination of areas with a certain flood risk (i.e. the 100-year flood zone) and setting up certain land-use requirements for these zones (67). In Germany, the area affected by a 100-year flood plays an important role for flood risk management (69). In this area, land use is often restricted, and most flood defences (e.g. levees, flood retention basins) are designed to protect up to this flood level (70).
Spatial planning can also play a role in limiting fatalities by optimising the possibility to reach safe places in case of flooding, be it within the flooded region (vertical evacuation, for instance to higher floors or designated flood shelters) or out of the affected region (horizontal evacuation). In addition, spatial planning can facilitate the evacuation of people away from threatened areas by making sure the main road network is elevated and thus able to be used longer in case of flooding (67). Old levees or local embankments can potentially be used for this and may have an extra compartmentalisation effect (68). Such compartmentalisation could limit the flood extent and thus fatalities and damage as well (67).
Flood risk reduction via private damage-reducing measures
During recent years in Germany, private responsibility for flood damage reduction has been increasingly emphasised and embedded into flood risk management (71). According to § 5 of the German Federal Water Resource Act that was enacted in 2009, every person that could be affected by a flood is obliged to undertake appropriate actions that are reasonable and within one’s means to reduce flood impacts and damage (72).
Adaptation strategies - Flood Risk Management Directive
The Flood Risk Management Directive explicitly relates the impacts of climate change to management of floods from surface waters and along coastlines. Bases for action and planning, such as six-year risk analyses, danger/risk maps and flood-risk management plans, are regularly adapted in light of the latest findings with regard to the impacts of climate change (23).
Adaptation strategies - Insurance
Insurance for flood damage is already possible. The insurance industry assesses the risk of damage to a building on the basis of a zoning system that takes into account not only the flood risk itself, but also the risk of torrential rainfall and backwater build-up. To date, however, there has been little demand for such damage policies. Nevertheless, since insurance for flood damage is a significant factor in the context of individual flood control precautions by the public, the possibility of introducing compulsory insurance for damage due to the elements, such as flooding, hail and windstorms, has already been discussed – most recently in the wake of the Elbe floods in August 2002 (24).
Adaptation strategies - Emergency preparedness
There are lessons to be learned from the 2002 floods for a.o. emergency preparedness. Both in the Czech Republic and in Germany, hospitals were affected by the floods.
In Dresden, five hospitals, with a total of >5,000 beds, were evacuated when they were surrounded by water. At the flooded hospitals, many of the electrical services and computer server facilities were installed in underground ducts. It is questionable whether it is beneficial and cost-effective to install sensitive technical equipment underground when there is a risk of flooding. Emergency equipment should be placed at a relatively high level in the building (50).
In the Czech Republic, the floods caused power outages, making it difficult or impossible to inform and communicate with staff and patients in the affected hospitals. Communication equipment that works without electricity and reaches both staff and patients in all hospital wards must be installed. As a result of the floods, many computerized case record systems were non-functional. Secure patient reports should be backed-up on computer servers outside of the hospitals. This source must be capable of quickly supplying hard copies (50).
There is also much to be learned from the German Defense Forces’ air support capability for the large-scale evacuation of severely ill patients over long distances. In the future, the procedure for the long-distance transportation of a large number of severely ill or injured people should be clarified in national plans. The plans must be able to be implemented on short notice. Coordination and management of a large-scale evacuation must be clarified and practiced. Helicopters for short-distance transportation and planes for long-distance transportation are the best ways to evacuate patients from hospitals. Hospitals should have helipads above possible flood levels (50).
Adaptation strategies - EU Directive on flood risk management
The new EU Directive on flood risk management, which entered into force in November 2006, introduces new instruments to manage risks from flooding, and is thus highly relevant in the context of adaptation to climate change impacts. The Directive introduces a three-step approach (2):
- Member States have to undertake a preliminary assessment of flood risk in river basins and coastal zones.
- Where significant risk is identified, flood hazard maps and flood risk maps have to be developed.
- Flood risk management plans must be developed for these zones. These plans have to include measures that will reduce the potential adverse consequences of flooding for human health, the environment cultural heritage and economic activity, and they should focus on prevention, protection and preparedness.
The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Germany.
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- Mitchell (2003)
- Barredo (2009)
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- Höppe and Pielke Jr. (2006), in: Barredo (2009)
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- EEA, JRC and WHO (2008)
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- Barnolas and Llasat (2007), in: EEA, JRC and WHO (2008)
- Lehner et al.(2006); Dankers and Feyen (2008b), both in: EEA, JRC and WHO (2008)
- Christensen and Christensen (2003); Kundzewicz et al.(2006), both in: EEA, JRC and WHO (2008)
- Palmer and Räisänen (2002), in: EEA, JRC and WHO (2008)
- Kay et al. (2006); Dankers and Feyen (2008), in: EEA, JRC and WHO (2008)
- Andréasson, et al. (2004); Jasper et al.(2004); Barnett et al.(2005), all in: EEA (2009)
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