Vízügyi Közlemények, 1973 (55. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

(97). whicli carbonates are known to precipitate. The analysis must yield information about the rate of carbonate precipitation, the production pressure as a function of well yield, the optimum feed of acid and corrosion control additive, as well as the depth of injection. In Chapter 4 the substance precipitated and the structure thereof, further the practice adopted for removing deposits arc described. This includes the details of the equipment used for feeding the acid ( Fig. 9). Tiie diverse tanks used for gas- and salt precipitation are shown in Fig. 11. Chapter 3 is devoted to the chemical composition of thermal waters and to the tendeneg to salt precipitation. The detailed chemical analyses of water from wells involved in the study have been compiled in Table I, whereas Table 11 shows the principal chemical components present in the 47 wells, where salt deposits have already caused difficulties in operation. Relying on these data the relationship between the chemistry of thermal waters and the danger of salt precipitation is examined. This investigation, however, failed to reveal any single component, on the basis of which the danger of salt precipitation could be predicted. No more is indicated than that within particular areas salts are more likely to be deposited in the wells where salts are present at higher concentration in the water. The location of the 47 wells is shown in Fig. 12. In Chapter 6 the principal chemical components of thermal waters in Hungary and the types of these waters are reviewed on the basis of data gained from the 38(5 wells in the country. The occurrence of the most frequently encountered iodinebromic (Fig. 13), as well as alkaline-hydrocarbonate type and sulphate thermal waters is shown in Fig. 14. SEEPAGE LOSSES FROM IRRIGATION CANALS by F. Horcher and Dr. Z. Szigyártó, Civ. Engrs. (For the Hungarian text see pp. 423) At the Research Institute for Water Resources Development systematical investigations have been conducted for the past 10 years in the area to the East from the Tisza River, in the canal network attached to the Eastern Main Canal diverting water from above the Tiszalök Barrage, or more precisely in the irrigation section K.IV. The objective of these investigations is to improve the design and the operation regulations of irrigation canal networks. A comprehensive review is presented in the paper on the series of experiments, by which —relying on experiences gained earlier [1-6]—the variations in seepage losses from the K.IV. section-principal canal were studied regularly in the period from 1967 to 1971. The conditions relevant to the experiments are described in section la, emphasising that the canal selected for experimentation purposes is representative of the canal network supplying irrigation water in the area (Fig. 1 ). The organization of the experiments ( Table I) is outlined in section lb. The main consideration was to determine water losses at the end of each year under identical conditions, in order to provide the opportunity for several checks on the reliability of the experimental results. In section 2 the processing of the experimental data is described, while these are discussed and evaluated in section 3. Relying on the data compiled in Table II and illustrated in Fig. 2 the main conclusions are summarized as follows: The canals supplying water to the irrigation developments from the Tisza River are excavated in cohesive soils. In these canals, provided they carry water in the entire irrigation season, the process of silting (colmatation) is completed within a few years time. After this period seepage losses become virtually constant (disregarding very slight fluctuation therein). This steady seepage results in very low seepage losses and at least in the alkaline, impervious and semi-impervious clay soils, classified according to type on the basis of the index of plasticity, these losses can be predicted by applying the formula of