Vízügyi Közlemények, 1967 (49. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

(4 3) density of 1.65 tons/cu.ni was specified and attained by spreading 20 cm thick layers over which a vibratory sheep's foot roller was passed 10 times. During construction density was checked by nuclear methods. Completion of Lhe work is scheduled for 1967. 3. Dávid, L.—Gál, T.—

Török, L. Civ. Engrs.: Study of conveyance in the Eastern Alain Canal. (For the Hungarian text see pp. 267) The Eastern Main Canal supplies irrigation water to parts of the Great Hungarian Plains east from the Tisza River. In 1965 it was found necessary to divert a discharge of 45 cu.m/sec through the navigation lock at the Tiszavasvár headworks, whereas the canal has been designed originally for a discharge of 35 cu.m/sec only. In order to shed light on this discrepancy, further on contradictory data on the conveyance of the Eastern Main Canal field observations were carried out between the 19th and 23rd October, 1964. During the experiments it has been endeavoured to maintain a steady discharge of about 40 to 45 cu.m/sec over the upper reach of the canal (Figs. 4 and 9). From the results it was concluded that discharges of this magnitude can be conveyed for extended periods, by slight modifications to the bank protection works and parallel interception ditches of the Main Canal. Between stations 5 to 45 km the necessary construction works call for an investment of approximately 4.5 million Ft-s. From observation data the velocity coefficient of the Main Canal was calculated at к — 40. -5. Hankó, Z., Dr. С. E. and Miss Akantis, Zs.: Studies on flood flow conditions at lhe 2nd barrage on the Tisza River. (For the Hungarian text see pp. 283) In 1965 flow conditions occurring at times of high water around the 2nd barrage on the Tisza River (at Kisköre) were studied in an undistorted model to scale 1 : 75 at the Research Institute for Water Resources Development. In the first phase of these studies scales were checked and correct construction of the model verified. In connection with the determination of the resistance produced by the structure a relationship has been developed between stage and differential head measured between a tailwater and headwater section. Maximum backwater (differential head) at times of normal high-water operation was found to remain below 30 cm. Discharges through individual parts of the structure were determined by a special series of observations, the results of which were used to prepare rating curves for the weir, the navigation lock and the flood gates in the high-water bed for cases of individual and combined operation. During the flow studies oscillation phenomena were observed. In fact the water flowing around the structure started oscillating with an amplitude of 75 to 150 cm and waves started to travel upstream from the weir. At the tailwater side of the weir a series of vortices was observed to separate. The Kármán-type separating vortices were found to have a twofold effect, inasmuch as they created surface waves detrimental to the banks and caused increased scouring in the tailwater bed at the junction of vortex series separating adjacent from piers. Founding on these observations modifications to the original design were recommended, aiming at the elimination, respectively minimization of the above unwanted phenomena. Recommendations included questions relating to the hydrofoil shaping of the piers by which the effect of separating vortex series could be eliminated. 5. Pataki, N., Civ. Engr.: On the first domestic application of wooden «ell filters combined with plastics. (For the Hungarian text see pp. 293) Operating conditions of producing wells are fundamentally governed by the well filter. Wooden well filters combined with plastic were first applied experimentally using SBF-OBO pipes (Table I

) made available for this purpose by Schönebecker, Ltd. Germany. The pipe is easily assembled and has very good strength characteristics (Table 111). The experimental well was sunk, as indicated in Fig. 5, into Pleistocene layers. Yields obtained from a well constructed with conventional filter of asbestos-cement and from the experimental well were compared ( Figs. 9 and 10 ). Pumping tests demonstrated the considerable advantages attainable by the use of Schönebecker type filters.