Vízügyi Közlemények, 1965 (47. évfolyam)
4. füzet - Rövidebb közlemények és beszámolók
<87) 2. On the reach between Tiszalök and Polgár the formation of floods is considerably influenced by the operation of the Tiszalök Weir. 3. On certain reaches the development of flood stages is strongly affected by sedimentation processes in the areas closed by summer dikes raised in the flood plain. BRIEF PUBLICATIONS AND REPORTS 1. J. Dudás and L. Szitkey : Degree of provision with public utilities of water supply and drainage for the population in different countries of the Earth. (For the Hungarian text see pp. 374) As regards the degree of supplying the population with water-conduit and sewer systems, the value of world average amounts to 30 — 20 per cent, which may be explained by the fact that the most densely inhabited countries of the Earth are lying in economically underdeveloped areas, where even the concept of dwelling does not agree with that considered in European sense. Thus, to attain the level of world average, can be the aim of underdeveloped countries only. A more correct picture is obtained, if only economically developed countries are laken into consideration, where water supply utilities are provided in 70 per cent and drainage systems in 60 per cent. As data compiled in Table 1 show, it is in the most developed countries, that a maximum degree of supply with water-conduits and sewers and a minimum difference between supplies for town and village inhabitants can be experienced. The countries of the Earth can be classified into six groups in this respect: countries with complete, favourable, good, medium and poor supply, and finally those being yet in an initial stage. 2. O. Haszpra , civ. eng. : Head losses clue to contracting transitions of canals with trapezoid profile. (For the Hungarian text see pp. 380) Author demonstrated in his previous papers (see references 1., 2) several benefits of broken-plane transitions for canals with trapezoid profile, in these, however, only a qualitative comparison between hydraulic behaviours of transition surfaces was dealt with. In the present paper the formulae of losses due to the individual transitions are discussed. The head of the broken-plane transition developed according to Fig. 2, coming about between the canal sections characterized by the geometric data in Fig. 1, is determined for several transition types in a general form. The general formula (1) of head losses is valid for transition types with characteristics given in Table 1, while Eq. (5 a), unified in dimensional respect, can be considered as standard formula for geometrically similar types between the limits given by ob and 5c. The values c, p and n for the individual transition groups are shown in Figs. 3, 4 and 5. Between Figs. 4 and 5 the interpolation (14) is possible. A less accurate but very simple solution is given by the formula of loss (16 a), where the value of A ranges from 0.86 to 1.16. For estimation Eq. (16 b) can be used under the conditions (16 c-f). 3. L. Török: Building experiences with mesh-reinforced concrete linings and concrete shell canals. (For the Hungarian text see pp. 389) The lining slabs, having a thickness of 25 to 30 mm and a surface area of 50x130 cm resp. 50x180 cm, are made of an aggregate with 20 mm maximum fraction and with a fineness modulus of 3.50 to 3.70, applying a cement quality of 500 kg/sq. cm cube strength and a cement ratio of 300 kg/cu.m, at a water-cement ratio of 0.60. As reinforcement, a simple rib wire mesh of 10 x20 mm size or ordinary fencing wire is used. A frame of 3 mm diameter provides protection for the edges of the reinforced concrete slabs. In order lo permit manual handling, the maximum weight of the slabs should not exceed 60 to 70 kg. In the formwork several slabs can be made simultaneously (Fig. 2); their curing requires a period of 7 to 8 days. The concrete slabs are suitable for lining earth channels with 1 : 1 slope (Fig. 3). At the contact of slope and bottom, joint laths are to be applied. Setting-in may be continuous (Figs. 5 to 6).
