River floods Romania
Trends in the past
In Eastern Romania, the river discharge regime is characterized by a maximum in the spring (snowmelt) and a minimum in the autumn. An analysis of weather data in the region over the period 1950–2006 showed a statistically significant increase of annual and summer precipitation at three out of six weather stations (an increase by 0.1 – 18% annually, and by 13 - 38 % for the summer) (33). No significant trends were observed for spring and autumn. Four out of six weather stations showed statistically significant decreasing precipitation for the winter (a reduction by 25 - 46 %). An analysis of discharge data over the same period for small rivers that flow into either the Prut River or the Siret River (tributaries of the Danube) showed a statistically significant increasing trend for 23 % of the analyzed rivers on an annual basis and for all seasons separately. The number of rivers with significantly increasing trends was highest (47 %) for autumn, followed by summer (29 %). Only one river showed a statistically increasing discharge trend in spring (33).
The floods of 2005 and 2006
Romania is known as one of the most flood-prone countries in Europe. Floods killed 1,000 people in 1926; 215 people in 1970; 60 people in 1975; 108 people in 1991; and 33 people in 1995 (28).
Heavy rain in April and May 2005 caused the worst floods since 50 years in Romania. The floods and storms in Romania, killed 76 people, caused at least 1.66 billion Euro in damage. This represents 2.1% from Romanian GNP. Flooding has also affected about 656,392 ha agricultural land, 10,420 km roads, 23.8 km of railway, 9,113 bridges and foot bridges and contaminated 90,394 wells (21).
In 2006, the extreme floods between April and August were among the most devastating natural disasters from recent Romanian climate history (the most devastating during the observation period 1840-2006 (27)). Although there were no human victims, the extent of the damage and the number of evacuated people surpassed by far the floods of 1970, one of the worst floods that hit Romania. Romanian officials ordered the controlled flooding of thousands of hectares of unused agricultural spaces to prevent further damage in cities across Romania. Estimations show that during April – May interval, 12 counties were affected, and the total economic damage is over 1% from Romanian GNP. The number of affected localities is 160; the estimated number of affected homes is 10,000. About 600 km of roads and 300 bridges were damaged, and the total farmland affected was 21,000 ha (21).
Poor governance capacities
Some of the main factors enhancing nature's “protest against global warming” are: poor sewage within the towns, illegal deforestation of hills or mountains slopes, dirty river banks, lack of citizens' education and responsibility, slow communication between different authorities, absence of specialized equipment, and in some cases, political or economical interests. Romanian authorities, having in mind the floods of 2005 and 2006, try to prevent these disasters or to mitigate their effects, but up to now there has been a big gap between theory and practice, mainly because of the complexity of the actions to be taken, which require time and money (22).
Contaminated and toxic waters
Many Eastern European cities that are prone to floods are in close proximity to industrial areas, mining operations, or are host to brownfield sites. As a result, people and settlements in the region run a significant risk to be exposed to contaminated and toxic waters. For instance, in 2000, a flood in Romania (Baia Mare) resulted in the breach of a tailings pond and of cyanide-laced waste from a gold mining operation being wasted into the Tiza and Danube Rivers. The accident not only affected the ecosystems of these rivers, but the drinking water of approximately two million people in Hungary. Similarly, flooding of a chemical plant in the Czech Republic in 2002 resulted in chlorine and other chemicals being washed into the Elbe and the deposition of dioxins on the shores of the River (29).
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 (31).
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 (45).
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 (24).
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 (25).
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 (25).
Adaptation strategies in Romania
Some of the proposed adaptation strategies are (27):
- elaboration of new design standards of flood protection works;
- introducing risk maps into regional and city development plans;
- promotion and extension of flood risk insurance;
- education of the population on how to act before, during and after a flood.
More room for the Danube
Falling within the territories of 19 European states, the 801,000 km2 Danube River basin is home to 81 million people. The Lower Danube comprises about 860 km of the 2,800-km long river, downstream of the Iron Gates Dams through the Danube Delta, before it empties into the Black Sea. Conversion of floodplains for farming and other development has seen 95% of the upper Danube, 75% of the lower Danube and 28% of the delta’s floodplains cut off by dykes. This has exacerbated flood peaks. Climate change is expected to increase the frequency of floods and droughts (23).
Along the lower Danube River, the restoration of floodplains is providing room to retain and safely release floodwaters. In 2000 WWF secured agreement from Bulgaria, Romania, Moldova and Ukraine to restore 2,236 km2 of floodplain to form a 9,000 km2 “Lower Danube Green Corridor.” Cut-off from the river by dykes, these floodplain lands are currently of marginal value for primary industries, and once restored, will be of similar scale as the area inundated in the 2005 and 2006 floods. As of 2008, 469 km2 of floodplain has been or is undergoing restoration, enhancing local peoples’ livelihoods and nature conservation. Each hectare of restored floodplain is estimated to provide €500 per year in ecosystem services, helping to diversify the livelihoods of local peoples (23).
Floodplain restoration along the Danube is an example of ecosystem-based approaches to adaptation. These approaches have great potential for climate adaptation. For example, flood-protection dykes along the Danube River in central Europe have exacerbated past flood peaks, leading to massive flood events that have led to average annual costs of US$164 million (32). With the threat of larger and more frequent flood events under future climate change, a shift in management to a more integrated approach has been instigated — retaining some hard infrastructure while removing much that was maladapted, and combining with Ecosystem-based approaches to adaptation in the form of extensive floodplain restoration. This new climate-resilient system now provides US$700 per hectare in flood control, enhanced fisheries, forestry, nutrient retention and recreational benefits (32).
Contaminated and toxic waters
Development of cities should be prevented in areas that are vulnerable to toxins, contaminants, or other health hazards that may arise as a consequence of the flooding of industrial and mining operations or brownfield sites. At the same time, concerted efforts need to be made to relocate existing industrial plants out of floodplains and to remediate brownfield sites (30).
Adaptation strategies - General
Non-structural measures are in better agreement with the spirit of sustainable development than structural measures, being more reversible, commonly acceptable, and environment-friendly. Among such measures are source control (watershed/landscape structure management), laws and regulations (including zoning), economic instruments, an efficient flood forecast-warning system, a system of flood risk assessment, awareness raising, flood-related data bases, etc. As flood safety cannot be reached in most vulnerable areas with the help of structural means only, further flood risk reduction via non-structural measures is usually indispensable, and a site-specific mix of structural and non-structural measures seems to be a proper solution. As uncertainty in the assessment of climate change impacts is high, flexibility of adaptation strategies is particularly advantageous (26).
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 Romania.
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- Anderson (ed.) (2007)
- Mitchell (2003)
- Barredo (2009)
- Höppe and Pielke Jr. (2006); Schiermeier (2006), both in: Barredo (2009)
- Höppe and Pielke Jr. (2006), in: Barredo (2009)
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- EEA, JRC and WHO (2008)
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- Ramos and Reis (2002), in: EEA, JRC and WHO (2008)
- 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)
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- Andréasson, et al. (2004); Jasper et al.(2004); Barnett et al.(2005), all in: EEA (2009)
- Arnell (2004); Milly et al. (2005); Alcamo et al. (2007); Environment Agency (2008a), all in: EEA (2009)
- Dankers and Feyen (2008), in: EEA (2009)
- Săvoiu (2008)
- Constantin-Horia et al. (2009)
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- Ciscar et al. (2009), in: Behrens et al. (2010)
- Kundzewicz (2006)
- Kundzewicz (2002)
- Ministry of Environment and Forests (2010)
- www.emdat.be, in: Pollner et al. (2009)
- Gautam and Van der Hoek (2003), in: Carmin and Zhang (2009)
- Carmin and Zhang (2009)
- IPCC (2012)
- Ebert et al. (2009), in: Jones et al. (2012)
- Croitoru and Minea (2015)