Vízügyi Közlemények, 1958 (40. évfolyam)

4. füzet - VII. Kisebb közleménye

f 14) mented by geoelectric observations. E.g., it was the geoelectrie method that helped 1. Biczók to explore in 1925 the coarse layers of one of the abandoned beds of the Tisza River. These, although assumed in preliminary geological investigations, could not be revealed by test borings. In order to determine accurately the sequence of layers encountered during the boringprocess, different methods have been introduced for plotting the soil profile. The electrical logging suggested by the Schlumberger brothers in 1927 was applied in Hungary first in 1936. The y-ray well-logging, yielding information about loose layers accessible only by lining the bore hole, can be used effectively l'or the investigation of the soil profile. In Hungary this method was first applied for water exploration in 1950. Water-yielding strata of wells completed with filter layers can be determined by the rheometer method suggested in 1903 by the Hungarian engineer A. Wehlner, and successfully applied in the thirties by P. Mazalán. Complete results of a recent rheometer investigation are shown in Fig. 2. The population in the plain areas in Hungary rely on g г о u n d w a t e r for their water supply. Wells were dug until recently by local artisans on basis of practical experience. The first attempts towards scientific groundwater exploration were made in the second half of the last century, a nation-wide organization was, however, not started until 1929, when Prof. S. Rohringer initiated the establishment of an observation well system in the plains between the Danube and Tisza Rivers. At present the number of these observation wells totals abt. 2000. The first municipal water works drawing exclusively on underground water supplies was constructed after inclusive preliminary investigations at Szombathely in the early years of this century. The exploitation of aquifers extending along rivers was considered first to supply water to the districts of Budapest on the left shore of the Danube River. The river side gallery constructed, in 1808 is still in operation. The bulk of water supplied to Budapest is even now obtained from these aquifers. In the course of development shaft wells have been replaced by tube wells; in recent times mainly horizontal wells have been built. Similar water works have been constructed for the towns Győr and Vác in 1903 and 1928 respectively. К a r s t i с waters encountered in triassic rock formations are an important source of supply in Hungary. These waters constitute a serious challenge to the coal mines in the North-Western parts of the country. Efforts to control the ever impending danger of flooding resulted as early as 50 to 60 years ago, in the development of methods for the artificial tapping of karstic waters and in a thorough knowledge of the phenomena involved. The first karstic gallery and shaft serving purposes of water supply were constructed in 1908 in Felsőgalla. Subsequent to several similar installations serving industrial purposes the 40 m deep shaft and 370 m long gallery of the Pécs Water Works were built in 1931. Shafts driven at 45 deg. towards the deeper layers from the bottom serve the more efficient interception of karstic waters and are an interesting feature of this project. Artificial drains of karstic waters were developed in greater numbers following the increased expansion of industry after the forties. The artificial drain shown in Fig. 1 was also constructed in this period. The exploration of water resources is conducted on a national basis by scientific methods. A work entitled "U'uíer Resources of Hungary" was published by the Research Institute for Water Resources in 1954. Available data about surface waters, groundwater, and artesian waters are compiled systematically in this publication. Further aid to the exploration of artesian and ground waters can be obtained from the Hungarian Hydrogeological Atlas under preparation resp. from the groundwater map prepared under the guidance of A. Rónai and indicating the mean groundwater table [53]. A map showing the karstic water table has also been prepared for the Central Mountains of Western Hungary. Abt. 60 000 data on water quality for all wells used for drinking-water supply are recorded and filed at the National Institute for Public Health. Main hydrogeological particulars of essen tiallv all Hungarian springs can be obtained from the Geological Institute, where the geological map to a scale 1 : 25 000 covering the entire country is also available.