Vízügyi Közlemények, 1966 (48. évfolyam)
4. füzet - Rövidebb közlemények és beszámolók
(102) the landward face of the rockfill dyke with plastic foil (Fig. 2.). A cushion layer of reed mattress was placed between the foil and rockfill (Fig. 3). The plastic foil must be weighted down, slurry must be introduced at greater distance from the foil and sheets must overlap by 50 to 100 cm at transverse joints ( Figs. 4 to 8). The experiment was a successful one, construction costs were lowered by 285 Ft per running metre. The additional saving from preventing the escape of slurry amounted to 52 Ft per metre run. 4. Horváth, I., Civ, Engr.: Hydraulic study of revolving paddle sand trap (For the Hungarian text see pp. 539) The possibility of using revolving paddle sand traps was demonstrated by the favourable experiences gained with revolving brush aeration basins. A section through the model studied is shown in Fig. 1. Froude's model law was considered valid. Flow conditions were studied for different degrees of rotor submergence ( Figs. 2 a—d and За—с ). An area of uncertain flow conditions was observed in every case in the central portion of the cross section. The development of the flow pattern is considerably influenced by the baffle above the rotor. The recommended solution is shown in Fig. 4. 5. Perényi, К., Civ. Engr.: Main problems of water resources development in Iran (For the Hungarian text see pp. 545) Water resources development in Iran follows a central plan, activities of major importance are under the control of the Ministry of Water and Power. Major structures are realized according to a preset schedule coordinated with national development programs of economy. 70 to 80% of the 23 million inhabitants are occupied in agriculture, so that irrigation over 2.5 million hectares is of paramount importance. Border irrigation ( Fig. 1 ) is most commonly adopted. Large reservoirs, diversions and treatment plants have been constructed for industrial and good quality domestic supply (Fig. 2). Precipitation conditions (Fig. 3) over the country are highly variable, according to some sources 6, to others 4 main climatological regions can be distinguished. Reliable supply of water is mostly impossible without reservoirs. Existing and projected dams on the river system and some other major hydraulic structures are shown in Fig. 5. Dam building has a strong tradition ( Fig. 5) recent dams are of modern design, e.g. the Karadj Dam (Fig. G ) and the Safid Rud Dam (Fig. 7). In the development of underground resources ancient kharizes (Fig. 9) have been replaced by wells. As a consequence of unsuited well technology these artesian wells deteriorate sometimes ( Fig. 8.). Springs emerging at the toe of mountain slopes (Fig. 10) yield also considerable volumes of water.
