Research of many years conducted at Water Resources Research Center VITUKI, the institute coordinating hydrological research in Hungary, as well as former experiences have shown that water in Danube and that of the karstic thermal sources are hydrostatically connected. Since the level of thermal water in the karstic thermal reservoirs is higher by a couple of meters than that of Danube at any time, no water from the river can infiltrate into the karstic water reserves to pollute them because all the connection they have is purely pressure-related. For it has higher pressure, thermal water breaks out in the form of release springs even in the river-bed of Danube.
It is but a fact that deep drilling also contributed to the disturbance of water balance. Deep drilling done in Pest and in the Margitsziget in Budapest caused the natural output of these sources to drop and the static reserves to reduce. In the 1980’s, as a by-product of mining, i.e. an ever-increasing water extraction, caused the normal water level to drop rapidly.
Starting fronm the 1990’s, mines were gradually going out of business and the consequential decrease in the amount of water extracted slowed down the process.
For example, water inflow extraction at the mines at Dorog reached its peak in 1967. Its long term effect was beginning to put thermal water sources and spas in Buda to the risk of running dry. Beginning in 1977, the funnel-shaped lack in reservoir that came to existence due to the extraction was getting refilled gradually.
To demonstrate just how big such funnel shaped lack can be, the vicinity of Tatabánya is to serve as an example, where extraction reached its peak in 1974. In a matter of two decades, the water level under the sites of extraction subsided more than 70 meters.
Even they were one-upped by bauxite miners at Nyírád near Tatabánya, where subsidence reached 120 meters, having its effect felt in areas 40 to 50 km away. It was therefore small wonder that the Hévíz spa operators started to ring the emergency bell in an effort to save the source of the spa feeding Hévíz from sharing the fates of the nearly 100 other fountains streaming water in and around the area of Transdanubian Mountain range, like the Fényes-forrás (Sparkling Spring) at Tata, the Meleg-forrás (Hot Spring) at Gyepükaján or the Malomtó-forrás (Mill-Lake Spring) at Tapolca, to name only the well-known ones.
In: Vizeink Krónikája (Chronicle of Hungary's Water)
Edited by László Fejér
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László Fejér
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