Flash floods and Urban flooding Hungary
In the Hungarian Great Plains large areas have no natural drainage (1). Excess water on the Hungarian plains and flat lands occurs when precipitation or snowmelt water cannot infiltrate into the soil (mostly due to semi-impermeable upper soil layer) and fills the depressions of the flat land. In Hungary the elimination of water damages became a task of strategic importance in the past years, due to the increasing frequency of extreme events (3).
Local damage occurs mostly due to heavy but local rainstorm that will cause high runoff, which results in high floods of local, usually small, streams, inundating villages, washing away the dams of small reservoirs, etc. High erosion or even mud avalanches may also be the result of such extreme local weather events (3).
Flash flooding is one of the most frequent hazards in Hungary (5).
Vulnerabilities Hungary - In the future
Regional climate model projections for Hungary, based on the A1B emission scenario, project for the end of this century (1) an increased average temperature, mainly in the summer, and a higher variability of rainfall, especially in the summer and winter; (2) an increased number of tropical days; (3) an increased length of heat periods; (4) changes in the summer and winter precipitation; and (5) a slightly increased number of days with heavy rains (more than 30 mm). In response to climate change, and according to regional climate model projections for the periods of 2021–2050 and 2071–2100 compared with 1961–1990 under the IPCC A1B climate scenario (4):
- soil erosion hazard is expected to increase;
- drought hazard is expected to become a serious problem in mainly the south-eastern part of the country;
- wind erosion sensitivity is expected to follow the drought sensitivity changes in the spatial distribution of Hungary (south-eastern part), also with an increasing sensitivity, mainly caused by the soil and vegetation cover characteristics;
- flash flood hazard is expected to increase in the Transdanubian Hills and in the Northern Mountains;
- mass movements will show patterns similar to flash floods, but will probably not increase.
The combination of these hazards will probably show the most pronounced increase In the north-west of Hungary; in this region the actual processes are very active (4).
Adaptation strategies Hungary
In order to reduce the risk and damages that may be caused to human life and properties by catastrophes induced by extreme weather events, a government resolution was released and this ordered the establishment and operation of forecasting-warning system of emergency situations that may be caused by extreme precipitation events (3).
The solution of the management and drainage of the excess- and precipitation waters of settlements became a task that cannot be postponed. Planned management and control strategies are needed for this development work, especially in settlements where excess and precipitation waters create increasingly dangerous situations. Local water damage events of the past years indicate that the most vulnerable locations are the settlements of the Northern Middle-Mountain Ranges – mainly in the mountains Mátra, Cserehát, Zempléni and in the valley of the River Hernád. Storm-water storage options must be surveyed, also utilizing the analysis of meteorological data, and on the long term this must also be made for the flatland regions (3).
The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Hungary.
- Somlyódy and Simonffy (2004)
- Blanka and Mezosi (2012)
- Farago et al. (2010)
- Mezösi et al. (2013)
- Czigány et al. (2010), in: Mezösi et al. (2013)