Vízügyi Közlemények, 1967 (49. évfolyam)
4. füzet - Rövidebb közlemények és beszámolók
(4 3) into winter storage and. conventional summer irrigation, i.e. a combined method of application is used. From 250 mm of irrigation water 50 mm moisture can be realized in summer. When this is divided into 31 and 19 mm and by applying it in two parts, one in winter, the second in summer, operating costs may be reduced by as much as 35 l/ 4. With storage only this saving may be increased to 72%. FIELD TEST ON THE DESIGN OF IMPERVIOUS APRONS By D. Quirico, Civ. Engr. (For the Hungarian text see pp. 244) The author was inducted to writing this brief contribution by the paper „Investigations on impervious layers by stabilizing local soils" which appeared in 1966/3 of „Hydraulic Engineering " by J. Bogárdi and L. Gáspár. With reference to this paper a description is given of the field tests perpormed with the objective of evaluating the future technology of construction, determining water losses frem the basin enclosed by embankments constructed with the proposed technology and to obtain information on the durability of completed works. BRIEF PUBLICATIONS AND REPORTS 1. Csoma, J .—Szilágyi, J.—Zboraij, K., Civ. Enrgs.: Flow, sediment transportation and ice travel over the backwater reach Tiszalök. (For the Hungarian text see pp 249) From among the barrages projected on the Tisza River (Fig. 1 ) the Tiszalök Barrage was constructed first between 1950 and 54 at River Station 524 km. After completion observations have been started for determining the changes taking place over the reach affected. A review is first given of the papers devoted to flow conditions and discharges, sediment transportation, as well as ice travel conditions. Changes of the bed due to modified flow conditions are investigated then in the light of these results. It is concluded that a) no appreciable changes have taken place in high-water stages, but those corresponding to medium and low river flows have been modified considerably; b) over a few km long reach above the barrage section silt depositions can be removed by dredging only, whereas silting around the end of the backwater reach has already assumed serious proportions so that deterioration of the bed cannot be prevented any more by conventional methods of river training; c) the length of ice-run periods has increased, as has the amount of ice. The deteriorated reach, which presents an obstacle to the travel of ice must be corrected as soon as possible by river training methods. 2. Varsa, E. Civ. Engr.: Construction of the Köszörű-Yalley Dam. (For the Hungarian text see pp. 260) In connection with the development of the regional water supply system of the Mátra Mountains in North-Hungary a reservoir is being created by a dam across the valley of the Köszörű Creek ( Fig. 1). A reservoir space of 340,000 cu.m will be available after completion of the 21m high earth dam having a crest length of 147 m (Fig. 2). A reinforced concrete structure, combining spillway, operational intake and bottom outlet, is designed and constructed to serve as temporary diversion for the period of construction. The foundation of the dam consists of sandstone. The intake tower is 27.42 m high. Water is conducted by gravity into the treatment plant, whence it is pumped into one of two basins of 250 cu.m capacity each. Construction work was started in April, 1966. The stilling basin and sections of the water conveying system were completed first, whereafter the intake tower was started. Rubber-plate seals were provided for the expansion joints. After stripping and preparing the foundation the clay core was placed and compacted. A dry
