Vízügyi Közlemények, 1965 (47. évfolyam)
4. füzet - Rövidebb közlemények és beszámolók
<84) According to investigations carried out so far in connection with the springs, the interactions and harmful changes are concentrated in the surroundings of the Margaret Island, mostly exploited by withdrawals. It is not surprising at all that the natural water balance has become upset by the forced water exploitation conducted for decades, since the depressions of water production establishments, made in a great number within a relatively small area, came into contact with each other and this resulted in a permanent drop of water level. The fact of this decrease in water level elevation, however, proves not more than a local overproduction. On the basis of data available so far, the huge, karstic water reservoir , consisting of confined and unconfined sections and having an extension of several sq. kilometres in the environs of Budapest, can be decomposed to systems that are in interconnection and in liydrological equilibrium, but cannot be determined accurately for the time being. Differentiation should be made between karstic reservoirs with cold and hot water, getting in contact with one another along the line of the Danube. A rough distinction can be made between the warm water karst system (40 to 50° C) lying on the right side of the Danube and including the Gellért Hill as well as the area southeast of this, and the hot water system (70 to 90° G) on the left side, situated in the surroundings of the Town Park and Margaret Island. In the north the outlines of a system with lukewarm water (20 to 40° C) can be distinguished. In the area of hot water resources thermal flux anomaly cannot be considered as probable; it is much rather assumable that waters flow upwards from a major depth. Due to the large regional extension and continuity of the Trias karst formations, it is extremely uncertain to determine the geological drainage area, and the theory of recharge resulting solely from precipitation cannot be taken as valid when referred to the deep karst. A wide range of interferences in the major depths and potential water transfers are here possible, and even the boundaries of the presumable surface recharge area may extend farther than expected. As regards water replenishment of certain systems, the possibility of a two-directional relationship can be raised, i.e. that not only discharge is dependent on „recharge", but also "recharge" depends on water withdrawal. After all, the available amount of data proves insufficient to determine the quantity of permissible thermal water exploitation in Budapest. Trial borings must be deepened, up-to-date investigations carried out, and decision can be made only on the basis of facts and never on that of theories. The water supply of our baths is no longer satisfactory today, and the natural springs, by virtue of their character, are no stable water yielding systems. Water exploitation from borings is more reliable, provided that adequate technical conditions are ensured. The problem of relocating the line of baths should also be studied within the framework of a long-range plan, since the water amount of drowned springs, getting lost in the Danube, could be saved by increasing the depressions. Taking all these aspects into account, the leading idea of problem raising and discussion is that thermal water should be searched for with up-to-date methods, should be "mined" under correct technical conditions and managed with adequate economy. FLOOD CONTROL IN POLAND By B. Sipos civil engineer (For the Hungarian text see pp. 328) Flood control in an organized form has been in Poland since 1945. Since Poland made a great progress during the past 20 years as regards technical and social organization of flood control, from the relevant work and results highly useful conclusions can be drawn. This is discussed by author in six chapters. A report is given on topographical and meteorological conditions, geography, regime of streams, as well as on floodwater retarding structures in Poland in the 1st Chapter. The flood control line of round 3000 km length protects an area of 900,000 ha. The method used in assessing the damage caused by flood and in evaluating •certain areas from the aspect of flood control for the purposes of national economic
