Images of the Danube at exceptionally low levels have been circulating online, prompting the 1.5 million residents of the city to ask, quite reasonably, whether water restrictions could soon be on the cards. Budapest’s water supply — and that of some suburban settlements — depends entirely on the Danube. The chief executive of Fővárosi Vízművek has now explained how the capital’s water supply could fare even if river levels remain low.
Water restrictions along the Danube
Experts are almost unanimous that extremes in the Danube’s water levels will become more frequent in future. That means more stretches of very low water like the present one, but also more frequent flood waves. It is not only tourism and the energy sector that must prepare for this, but drinking-water supply too.North of Budapest, several settlements are already in a critical position.
In the Pilis area — including Szentendre, Leányfalu, Pilisborosjenő, Üröm, Solymár and Nagykovácsi — there is already enough drinking water only with the help of the armed forces, while in Zebegény second-degree water restrictions are in force. In Dunabogdány, Fővárosi Vízművek itself has urged residents to avoid non-essential water use in recent days, according to Világgazdaság.
Budapest’s water level is also extremely low, although it has risen in the past two days. According to water-management data, the low point came on the evening of 2 August, when the gauge read just 9 centimetres. By now that has risen to 20 centimetres. But that is not why Budapest’s drinking-water supply is holding up so well.
Two Danubes in Budapest
Géza Csörnyei, chief executive of Fővárosi Vízművek, explained on InfoRádió’s Aréna programme that drinking water would still be secured even at lower Danube levels. That is because it does not depend directly on the river’s current surface level. In effect, two Danubes flow through the Hungarian capital: one on the surface, and one beneath and alongside it.Beneath and beside the riverbed lies a gravel layer several tens of metres thick, formed over thousands of years by the river’s sediment. Water flows continuously through this gravel bed, parallel with the river.
Csörnyei likened it to an “invisible river”: even when the Danube’s surface level is extremely low, a significant amount of water is still moving underground. Fővárosi Vízművek uses this water — the bank-filtered source — to produce drinking water.The gravel layer is not just a carrier of water, but also a vast natural reservoir. It stores a large quantity of water, which can be accessed through wells. In the current spell of extreme weather, these reserves are what are keeping Budapest’s water supply secure.
Weeks, even months
According to the chief executive, Fővárosi Vízművek is continuously monitoring the operation of its wells, and the results so far are reassuring. Although output has had to be reduced at a few older wells, more than 97 per cent are operating normally and without disruption. Water quality is being checked more frequently and more strictly than before, and no adverse changes have been detected.Mr Csörnyei said the current extreme conditions have not yet exceeded the capital’s system capacity. The utility has sufficient reserves to meet demand safely for weeks, even months, in the present weather. He added, however, that this does not mean the water supply is limitless: every system has a physical ceiling.
Budapest’s position is helped by the fact that the capital’s water supply consists of several interconnected systems. If demand rises sharply in one area, available capacity can in some cases be redistributed. That is a major advantage over settlements with independent water systems. The chief executive cited Dunabogdány as an example, where the balance between local production capacity and consumption has already been upset, making restrictions necessary.
Rising demand
For the capital, the immediate challenge is not that water will suddenly run out, but that demand is rising sharply. In 39 to 40 degree heat, consumption jumps significantly, and prolonged drought has already dried up many household and garden wells. As a result, some uses have been shifted back on to the drinking-water network which were previously met by wells, cisterns or other alternative sources. At certain times, demand can rise by as much as three or four times.
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The system’s safety is also helped by the utility’s buffer reservoirs. These tanks and storage facilities provide reserves, so that even in the event of a technical fault, crews have a few hours to fix it. Power supply is planned for too: critical facilities have multiple feed-in options and generators can be deployed if needed.
More investment needed
The chief executive’s conclusion is that Budapest’s current water-security situation is not determined solely by the Danube’s surface level. The bank-filtered water base, the gravel layer acting as a natural reservoir, reserve well capacity, the interconnected network, storage tanks and tighter monitoring all together make it possible for the capital to cope with the present extreme weather.
Longer term, however, the current drought is a serious warning. Mr Csörnyei said it is not enough merely to replace old pipes: climate change may require greater capacity, more wells, more storage, more pumping stations and more advanced systems. The present situation therefore does not point to an immediate water shortage in Budapest, but rather to the investments that will be needed if the capital is to keep supplying residents safely in extreme weather.
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Watch the full interview with Mr Csörnyei:
