Hungary is situated in the Danube catchment, in the lowest part of the Carpathian basin consisting mainly of low plains. The rivers enter the national territory from the west, north and east and leave it again in the south. In Hungary we find the largest shallow lakes of Central Europe: Lake Balaton, Lake Velence and the Hungarian part of the Neusiedler See.
The water regime result from local geographical conditions
The Carpathian basis is part of the temperate climate zone and is under strong continental influence. It is the region where weather fronts of the most different directions and kinds meet. The annual precipitation varies from 300 mm to 1200 mm with a long-standing medium amount of 600 mm per year. The sun is shining an average of 2000 hours per year.
The water regime of the region, too, results from its geographical characteristics. From a climatic and hydrological point of view the national territory can be divided in to major regions: the region west of the Danube has more rainfall and is therefore supplied with water in a better way, while the eastern part of the country, mainly consisting of the Theiß catchment, is considerably dryer and often affected by drought periods.
Flood protection is very important
The surface threatened by floods and polder water amounts to 48,000 km2. i.e. 52 percent of the entire territory or two thirds of the cultivated surface. The danger level characterised by these indicators is the highest in Europe. The floods develop very quickly, even within hours in minor brooks. As to big rivers, a flood may take several months to run off. Highly dangerous are the devastating ice floods with a very fast run off.
The reason why flood prevention is so important in Hungary results from the fact that a flood plain area of 21,200 km2 lies below the high water level of the rivers. 1.8 million ha of agricultural land, 32 percent of railways, 15 percent of the roads of the country and 2000 industrial plants are located in this area. A quarter of the Hungarian population lives in this floodplain in more than 700 settlements.
In order to prevent flood damage measures of actual flood prevention are taken on the one hand, and measures of river regulation to improve run-off conditions on the other. A total of 4,200 km of flood protection lines are being put up, the major part of them consisting of earth dams. High water protection walls stretch over 30 km only, and high banks have a length of 286 km. The pressure of dams is relieved by bypass canals and emergency retention basins with a total capacity of 360 million m3.
Several hundred river bed cuts have been made in the course of river regulation, which shortened the rivers considerably. The bed of the Danube was shortened only by 70 to 80 km, while the Körös rivers were shortened by several hundred kilometres, i.e. by more than their original length.
Protection measures against polder water damage
Practically the entire area – the plains of the country, the low plains, where the valleys of the waters meet the plain – is threatened by water damage. Even the protected floodplains (the dike hinterland) are not spared from polder water. The large low plain of 43,600 km2 is completely exposed to flooding or wet conditions by polder water. Polder water is causing severe damage both in agriculture, in settlements without a sewerage and – in case of severe flooding – also to traffic lines.
As a consequence of the recent privatisation of agriculture, polder water prevention has to be focused on in particular. Even in an average flooding by polder water the existence of a large number of private farms is threatened because their crop land cannot be cultivated during the spring polder water.
Protective measures against polder water damage are taken, or rivers are regulated, which are classified according to their location in special areas of plain water regulation, the mountainous water regulation and settlement water regulation.
In the course of plain water regulation a network of canals of different sizes with a length of 42,600 km was built. In the mountainous region, water regulation shall prevent floods caused by a total of 70,000 km natural small rivers and protect the population from an immediate danger caused by these floods.
However, river regulation in settlements is still not sufficient. The situation is even more difficult, because almost every settlement has a drinking water supply system, while waste water treatment is only available in 45 percent of the settlements. Those communities, which do not have a sewerage have to expect a harmful rise of the ground water level.
More connections to mains and sewerage
In the framework of water supply the primary aim is to further improve the supply level and the water quality parameters. The share of apartments connected to the supply network shall be raised to 90 percent first, then the improvement of the technical quality and operational conditions shall lead to safe supply, the maintenance of pressure and the fast repair of breakdowns. A further programme, designed for the decades to come, shall finally improve the quality of water even further (taste, odour, clarity, mineral content).
In Hungary, ground water reserves are principally used for drinking water supply. The share of groundwater, which is close to the ground, is constantly decreasing due to pollution. Because of high treatment costs the share of surface waters in drinking water supply is rather small. Waste water disposal and treatment is closely related to the development of water supply, the quantitative parameters of which are favourable. However, those of sewerage and waste water treatment are less favourable. When compared to water supply it is lagging behind by 40 percent.
From the point of view of water quality, the situation is even worse, since only 45 percent of the waste water from communities connected to a sewerage are treated. The share of 100 percent efficient biological treatment plants for household waste water only amounts to 33 percent. The lack of waste water treatment led to a rise of the groundwater level under the settlements, to the pollution of surface-near groundwater and consequently also to the pollution of deeper levels of groundwater, and to the deterioration of surface water quality.
The aim as to the sewerage and waste water purification is to connect 65 to 67 percent of the people living in flats to the public sewerage and to connect 20 to 22 percent of people living in flats at least to a sound sewerage alternative. The remaining number of people, which is expected to gradually decrease, would have their wastewater percolated. Those industrial and agricultural enterprises willing to feed their wastewater into the sewerage, will have to pre-purify it, so that it can be treated together with household wastewater.
More emphasis on better water quality
An analysis of water quality conditions in those places where the rivers enter and leave the territory has shown that the water quality of those rivers passing through Hungary is not deteriorating there, on the contrary, in some rivers it is even improving with respect to some water quality parameters. The situation of the water quality in the still waters of the country, however, is not favourable. Even costly measures will be able to improve the situation only after sufficient water supplies have been secured. However, a final solution can only be expected from ordinances concerning wastewater and waste disposal.
Among the different kinds of underground water, it is especially the ground water reserves close to the surface that are most heavily polluted in the whole country. The deep level waters have generally maintained their original quality, but there are several places, where those are polluted, too.
Karstic water reserves are less protected by their covering stones than the deep ground waters, and also the waters filtered by the shores are constantly threatened. However, their situation is slightly better than some years ago due to the decrease in artificial fertiliser use. (Source: aqua press Int. 5/1999)
Manuela Prusa
