Vulnerabilities - Hungary

Fresh water demand

The total water abstraction in Hungary at present is about 6000 million m3/year, 75% of which is for cooling water use. From the remaining part, the public is the major user with 40%, the industry takes a little more than one quarter and agriculture uses the rest (irrigation 15%, fishponds 5%, animal breeding 15%) (1).

A recent assessment has shown that the specific water demand for irrigation can increase by 20–50%, while the surface runoff and recharge of groundwater in the southeastern part of the country may be reduced by 30–60% and 25–80%, respectively (1).

In respect of the future, water demand is anticipated to remain more or less unchanged in industry and municipalities. The bottleneck is formed by the agricultural sector. Here many uncertainties are faced due to the existing, outdated irrigation system designed for earlier large scale state owned farms, the unavoidable shift from the present small plot structure to medium sized farms and impact of the EU accession. Irrigation demand will definitely grow, particularly in the Tisza valley where availability depends a lot on foreign uses and vulnerability to climate change impacts is high. The solution should be based on a number of hard and soft tools including pricing, planning with neighbour countries and the potential joint construction of reservoirs in upstream countries to cope with extreme events (1).

Fresh water supply from rivers

Hungary strongly depends on river outflow from other countries: 95% of the surface waters are of foreign origin (1). … Water management is a difficult task in many areas, due mostly to the low density of the river system. Overall, the less developed East faces many more problems than the Western part of the country (1).

The climate of Hungary will likely shift to a more Mediterranean one with more frequent extreme events. This would result in reduction in surface runoff, in soil moisture and recharge to groundwater. One of the serious consequences is less water available for increased water demand, especially for irrigation. … From a strategic viewpoint climate change’s likely impacts would be an additional, unpleasant element on already existing problems, primarily in the Tisza-valley, which has been already facing problems of water shortage (1).

Hungary relies on bank filtered water to meet one third of public water demand. All of the drinking water supply of Budapest for example derives from bank-filtered water of the Danube. The abstracted amount is only limited by the filtration capacity of the bank and since the discharge of the river is an order of magnitude greater than the abstracted amount there is practically no limitation from the resource side. The supply is therefore extremely secure especially when contrasted to the sensitivity to climate change of other groundwater resources (13).

Fresh water supply from groundwater

75% of the total abstraction (except cooling water) is from groundwater. Besides the traditional dominance of groundwater in drinking water supply (94%), abstraction of groundwater for industry and for irrigation has been gradually increasing, and nowadays it exceeds the amount used from surface water. This new situation may lead to non-sustainable exploitation. … Some karstic and porous aquifers in the east are already seriously overexploited: irrational mining activities in the Transdanubian Mountains resulted in drastic decline of karstic water levels. Lots of springs and karstic wetlands have disappeared (1).

Climate aridity will increase, with increasing surface temperature and heat dissipation, and decreasing precipitation. This will reduce drainage and water infiltration, the annual renewable hydrological reserves (especially in the summer), and soil humidity (9).

Fresh water storage in lakes and reservoirs

On the Hungarian Great Plain, droughts such as the one of August 2003 have caused extreme harm to agriculture practiced in this region, climatically classified as "semi-arid". The lack of water reduces not only agriculture, but also the development of industry and urbanisation. Cities and other communities demand more water than the quantity available from rainfall, and it has always been difficult to get enough water for settlements far away from rivers (8).

This has necessitated the construction of reservoirs on the Tisza, and two facilities have been completed, one at Tiszalök and the other at Kisköre (called lake Tisza). The latter has a 106 million m3 storage space developed between flood control levels. The water from the reservoirs is conducted through the Great Plain by the Keleti (East), Nyugati (West), Nagykunság and Jászság main canals to the Berettyó and Körös Rivers, enabling the development of the economy and recreation, even during periods of droughts (8).

Lake Tisza is the second largest freshwater body in Hungary and the largest artificial lake in the country. The original Kisköre Reservoir was built in 1973, as part of the River Tisza flood control project, and its filling was finished in the 1990s. The completed reservoir - renamed as Lake Tisza - is 27 km long with a 127 km2surface. The River Tisza’s length within the reservoir is 33.6 km. Lake Tisza is also a typically shallow lake, with an average depth of 1.3 m and a maximum depth of 17 m (10).

The water balance of lakes and ponds will deteriorate, the periods with low water level will increase and lengthen, and some lakes may in fact disappear (9).

Vulnerabilities - Lake Balaton

Lake Balaton’s internationally unique vulnerability situation is the combined result mainly of its very shallow profile and the fact that, through heavy reliance on tourism as a primary source of livelihoods, the socio-economic consequences of ecological deterioration can be severe and immediate (5).

For the first time since records began in 1865, four consecutive hot summers and low annual rainfall have sucked millions of gallons of water from the lake at the beginning of the 21st century, exposing large mudflats and forcing vacationers to walk far out into the lake before they can swim (4).

Lake Balaton in numbers

Lake Balaton is called The “Hungarian Sea” (1). The lake is located 100 miles south of Budapest. The lake was formed at the end of the last Ice Age over 10,000 years ago. It is fed by rainfall and snow, the Zala river in the south, andapproximately 130 underwater springs (7). When full, the lake is drained through the Sio-Canal further north. Some water is normally removed this way each year (4). Lake Balaton is a popular summer destination due to its warm, shallow water and sandy beaches. The lake is about an hour’s drive from Budapest and attracts approximately 1 million tourists each year, as well as day and weekend visitors (7).

Located in the Transdanubian region of Western Hungary, the Lake Balaton catchment area including the lake itself is 5775 km2. Lake Balaton is the largest lake in Central Europe. With a surface area of 593 km2, 78 km length, 7.6 km width and an average depth of 3.2 m, it is one of the shallowest large lakes of the world (5).

Detailed meteorological data are available since 1921. Average precipitation in the catchment area is 686 mm/year. A slight negative trend in precipitation is observable over the last 80 years. Intensity of precipitation is typically a few 10 mm/day, but several strong storm events occur in summer with intensities exceeding 10 mm/h (5).

Most of the tributaries of Lake Balaton are short, steep watercourses with intensive flash floods in case of storm events. During flash events the maximum discharges may reach as much as 100 times the average. The average slope of cultivated land is 5.6 degrees, but 33% of it lies on slopes greater than 5 degrees where surface runoff may result in significant washout of nutrients and soil erosion (5).

Artificially created water surfaces, such as the Kis Balaton reconstructed wetland in the westernmost end of the lake and fish ponds in the watershed, result in increased evaporation and reduction of inflow to the lake. The total area of such surfaces is about 40 km2 and the resulting excess evaporation is estimated to be 30-35 lake mm/year (5).

Water quality

Lake Balaton now has a decades-long history of eutrophication. The first definite signs of eutrophication were observed in 1972, while in 1982 the first mass bloom of algae occurred, forcing the government into action. The measures taken included, among others, sewer development, sewage treatment plant effluent diversion to neighbouring watersheds, introduction of phosphorus removal at sewage treatment plants, and reconstruction of the Kis-Balaton (K-B) wetland as a water pollution control facility (5).

The most severe algal bloom in the history of Lake Balaton occurred in 1994. Post-1994 water quality stabilized and somewhat, though probably not irreversibly, improved due to the temporary drastic reduction in fertilizer use after the collapse of state farms and agricultural cooperatives in the early 1990s. As of 2003 fertilizer use is still less than 20% of the amounts used in the early 1980s. However, fertilizer application is expected to rise, since soils have become increasingly nutrient depleted and the gradual introduction of EU farm subsidies will likely result in increased fertilizer use and a consequent rise in nutrient load on the lake (5).

Disturbed water balance?

The lake has a single outflow with a sluice (constructed in the second half of the 19th century) which is used to control water level. On the basis of data of the past hundred years, water balance is positive: evaporation equals runoff while outflow equals precipitation (about 600 mm/year). In spite of it, due to natural variability, water level fluctuation has been significant (2).

Considering recreational and flood prevention needs, about three decades ago seasonally variable upper and lower control levels were introduced (the presently authorized range of regulation is between 110 cm maximum and 70 cm minimum, measured at the Siófok gauge (5)). Below the latter one, release is not allowed. However, it is obvious that only the upper level can be really regulated. There are no particular tools available to avoid low extremes: the success of the strategy depends on keeping high water levels and the natural variability of the water regime (2).

The control scheme functioned satisfactorily till 2000, when an extreme drought period started. In 2001, for the first time that evaporation exceeded the sum of precipitation and runoff. This was repeated in 2002 and 2003, and the lowest water level of the past 50 years was observed (the drop was about 0.7 m). Public concern grew and the idea of water transfer from other watersheds was raised. Various alternatives were analyzed, primarily from technical and economic viewpoints. The cheapest transfer from the close medium size River Rába was recommended (2).

The vulnerability of the lake to potential climate impact is remarkable: under the assumed scenario for 2035, the frequency of the low water conditions that occurred at the beginning of the 21st century (once in a few hundred years) can grow by an order of magnitudes (to once in a few decades). The reason is that climate change influences all three elements of the natural water balance (precipitation, runoff and evaporation) negatively (2).

According to the National Meteorological Service (NMS) of Hungary, there has been demonstrable warming in Western Hungary over the last two decades, coupled with a pattern of below average annual precipitation. The situation appears to be particularly sensitive due to Lake Balaton’s extremely shallow profile. The frequency of atmospheric circulation patterns associated with low water levels in Lake Balaton is expected to increase in the future according to mainstream global climate models and scenarios (6).

If the frequency of years with negative water balance indeed increases in the future, as indicated by applicable climate change scenarios, Lake Balaton and the coupled socio-economic system are expected to emerge as a highly sensitive and internationally unique indicator of vulnerability to global change (3).

Europe: five lake categories

There are almost one and a half million lakes in Europe, if small water bodies with an area down to 0.001 km2 are included. The total area of lakes is over 200,000 km2; in addition the manmade reservoirs cover almost 100,000 km2. The response of European lakes to climate change can be discussed by dividing the lakes into five categories (11):

Deep, temperate lakes

Typical representatives of this class are e.g. Lakes Maggiore, Ohrid, Geneva and Constance with mean depths of 177, 164, 153 and 90 meters, respectively. Due to the great depth and relatively mild winters, there is usually no ice cover. The future climate change in Europe may suppress the turnover in deep lakes. This implies the enhancement of anoxic bottom conditions and an increased risk of eutrophication. The oxygen conditions can also be anticipated to deteriorate due to increased bacterial activity in deep waters and surficial bottom sediment.

Shallow, temperate lakes

Balaton (600 km2, 3 m) in Hungary and Müritz (114 km2, 8 m) in Germany belong to this class. Increasing water temperatures may result in intensified primary production and bacterial composition. The probability of harmful extreme events, e.g. mass production of blue-green algae, will increase. The impacts may extend to fish life; changes in species composition and reduced fish catches will be anticipated. The use of the expression 'thermal pollution' is well justified for these lakes.

Boreal lakes

Ladoga (17 670 km2, 51 m), Onega (9670 km2, 30 m) and Vänern (5670 km2, 27 m) are the largest in this class, being also the three largest lakes in Europe. This group includes about 120 lakes with an area exceeding 100 km2. Most lakes of the boreal zone mix from top to bottom during two mixing periods each year. Shortening of the ice cover period will be the most obvious consequence of climate change in these lakes. This could improve the oxygen conditions in winter and spring.

Arctic lakes

These are mainly small water bodies in northern Scandinavian mountains and in the tundra region. Arctic lakes are generally considered to be particularly sensitive to environmental changes. Melting permafrost may seriously threaten the ecosystems of arctic lakes. In some cases the whole lake may disappear as a consequence of ground thaw and enhanced evaporation.

Mountain lakes

To this class belong all high altitude lakes in central Europe and also those located in southern Scandinavia. Even if mountain lakes were connected by channels, physical and ecological constraints limit species migration between them. In a warming climate, there is no escape route; the only possibility for survival is adaptation.

South-eastern Europe: four types of lakes

In order to discuss the effect of climate change to lakes in south-eastern Europe, the region is divided into three climatic sub regions. The main characteristic in this subdivision is the mean temperature in January, because the severity of winter has an essential influence to the lakes. The sub regions and the anticipated influences of climate change, around the year 2050, are as follows (11):

The Mediterranean sub region

In today's climate the mean temperature varies in January between +10 and -2°C, in July it is generally 20 - 25°C. This sub region covers the narrow coastal area on the Adriatic Sea, most of the Greek territory and the lowlands on the southwest side of the Black Sea.

Only the smallest lakes have short ice cover season every winter in today's climate, in the future climate ice will be almost non-existent. Summertime water temperatures will get very high, leading to algal and water quality problems. Water balance will be negatively affected by climate change; evaporation will increase and inflows tend to decrease. The use of lakes as water sources, e.g. for rising needs of irrigation, will be limited.

In today's climate, the runoff in the Adriatic part of this sub region is generally over 1000 mm, while it ranges between 30 and 200 mm in the vicinity of the Black Sea. The difference of lake precipitation and lake evaporation is 200 - 600 mm in the former area, whereas it is between -200 and -400 mm in the latter. In the climate of 2050, shallow lakes in the latter area will become intermittent and reservoirs will have considerably high water losses.

Northern lowlands

Mean temperature in January is between -5 and -2°C, in July around 20°C. This sub region covers large parts of Hungary, eastern Croatia, central parts of Serbia, southern and eastern Romania, and Moldova. As to the runoff, this is the driest area in south-eastern Europe; in Hungary and on the Black Sea coast annual runoff is locally less than 20 mm. The difference of lake precipitation and lake evaporation is between 0 and -300 mm.

In today's climate most lakes in this sub region mix from top to bottom during two mixing periods each year and have an ice cover for 1-3 months. They may still freeze in 2050, but the possibility of ice-free winters will increase. Adverse water balance changes may affect many lakes; intermittency and increased salinity can be anticipated.

Mountaineous regions

South-eastern Europe is topographically one of the most diverse regions in the world. In addition to two main mountain ranges, Carpathians and Dinaric Alps, there are numerous other ridges and plateaus. At highest elevations, mean temperature in January can be as low as -10°C and extremes below -30°C have been recorded. In July typical mean temperatures are between 10 and 20°C. Precipitation is generally abundant but very variable even at small scale.

Most lakes are located in river valleys, but smaller ones occur also at high plateaus and depressions. Ice cover season may be as long as 5-6 months, snow on lakes further reduces the penetration of radiation into the water mass. Some of the highest lakes mix once a year but mixing twice a yearis much more common.

Climate change may not cause very harmful changes in water balance of these lakes. Increased erosion by intense precipitation may lead to sedimentation and degradation of water quality. At lower elevations, the occurrence of ice cover may become uncertain. For water supply, the mountain lakes and river basins will probably be very important in south-eastern Europe in the future, because run-off may considerably decrease at lower altitudes.

Underground (karstic) lakes

This is a special type of lakes. Due to the karstic geology, there are underground lakes in the Balkan region. They are not immune to the impacts of climate change; in fact their water balance and ecology may be sensitive to changes of the quantity and quality of inflowing waters.

Adaptation strategies - Overview

EU policy orientations for future action

According to the EU, policy orientations for the way forward are (12):

• Putting the right price tag on water;
• Allocating water and water-related funding more efficiently: Improving land-use planning, and Financing water efficiency;
• Improving drought risk management: Developing drought risk management plans, Developing an observatory and an early warning system on droughts, and Further optimising the use of the EU Solidarity Fund and European Mechanism for Civil Protection;
• Considering additional water supply infrastructures;
• Fostering water efficient technologies and practices;
• Fostering the emergence of a water-saving culture in Europe;
• Improve knowledge and data collection: A water scarcity and drought information system throughout Europe, and Research and technological development opportunities.

Managed aquifer recharge

Comprehensive management approaches to water resources that integrate ground water and surface water may greatly reduce human vulnerability to climate extremes and change, and promote global water and food security. Conjunctive uses of ground water and surface water that use surface water for irrigation and water supply during wet periods, and ground water during drought (14), are likely to prove essential. Managed aquifer recharge wherein excess surface water, desalinated water and treated waste water are stored in depleted aquifers could also sup­plement groundwater storage for use during droughts (15,16). Indeed, the use of aquifers as natural storage reservoirs avoids many of the problems of evaporative losses and ecosystem impacts asso­ciated with large, constructed surface-water reservoirs.

Adaptation strategies - Hungary

Demand measures

Water use can be reduced through the price of water: real pricing led to about 50 % reduction of drinking water consumption and wastewater generation (1).

Water awareness is growing in Hungary: it is becoming more and more appreciated from the viewpoint of the economy and society. Meeting short-term demands is being replaced by seeking long term sustainable solutions: integrating water issues with land use management, environmental management and nature conservation, and finally with the economy and the society cannot be avoided (1).

Water transfer to Lake Balaton?

The ecological status of the lake does not justify water transfer from another watershed. The quality of the lake’s water remained favorable even under extreme low water conditions of the first years of the 21st century (2).

It was recommended to transfer water from the River Rába. Excess water from the River Rába, however, is limited (moreover, the water regime is similar to that of the Balaton catchment). Thus, safe and continuous lake water level control is not guaranteed. Not only would the transfer not prevent potential negative climate change impacts on water level, but it might risk the ecological status of surface waters of the Rába – Balaton region (change of the chemical composition of the lake’s water, increase of the external and internal nutrient loads, enhanced algal growth, proliferation of invasive species, etc.). In fact, the majority of the many sided impacts assessed were negative and none of them were positive (2).

Uncertain impacts of climate change on water level might be detected on a time scale of a decade or so. A precautious solution in this respect cannot be offered. At the same time, if low water level is retained for a longer period of time, negative ecological impacts might be the result. … in fact at the end we may accept a smaller and healthy lake rather than a morphologically unchanged one of potentially low ecological value. The dilemma is huge with many ethical, social, political and other implications (2).

Additionally it is proposed to increase the capacity of the single outflow, the Sió Canal, which would allow storing more water in the lake without flood risks, if once filling up already took place. This would allow to lift lowest water levels by about 20 cm (2).

References

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.

1. Somlyódy and Simonffy (2004)
2. Somlyódy and Honti (2005)
3. United Nations Environment Programma (UNEP) –DEWA/GRID Europe (2006)
4. www.planetark.org
5. United Nations Environment Programma (UNEP) (2005)
6. Weidinger et al. (1994); Bartholy et al. (1995); Watson et al. (2001), all in: United Nations Environment Programma (UNEP) (2005)
7. Rátz and Vizi (2004)
8. Burnod-Requia(2004)
9. Hungarian Ministry of Environment and Water (2009)
10. Rátz and Vizi (2004)
11. Kuusisto (2004)
12. Commission of the European Communities (2007)
13. UNESCO IHP (2005), in: Evans and Webster (2008)
14. Faunt (2009), in: Taylor et al. (2012)
15. Scanlon et al. (2012), in: Taylor et al. (2012)
16. Sukhija (2008), in: Taylor et al. (2012)