Vízügyi Közlemények, 1970 (52. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

(58) THE SPRINKLER IRRIGATION SYSTEM AT HAJDÜSZOVÁT AND EXPERIENCES GAINED DURING ITS CONSTRUCTION By Molnár, L. Civ. Engr. (For the Hungarian text see pp. 307) In the eastern part of Hungary, in the Valley of the Tisza River a huge water management project is being realized gradually with the objective of supplying irrigation water to agriculture in the region. Water to the eastern part of the area is supplied by the Tiszalök Barrage and the Eastern Main Canal completed 16 years ago, while the central part will be served by the Tiszabura Barrage now under construction. In the Tiszalök system a new model plant extending to 4300 hectares has been equipped for irrigation. Two agricultural cooperatives share the area affected. In Chapter 1 the preliminary studies are described, in the course of which careful economic computations and agricultural estimates were performed to justify the investment in irrigation development. The layout of the irrigation section (Fig. 1 ), the relevant technical data, as well as the data on state investment (I) and plant investment (II) are given in Table 1. The specific investment costs in Hungarian Forints are related to the old Hungarian area unit and to hectares. Experiences gained during engineering design are described in Chapter 2. The problem consisted of designing a sprinkler irrigation section with underground asbestos-cement distribution network for growing cereals. Water to the section is supplied by a pumping station ( Figs. 2, 3, 4) diverting water from the Eastern Main Canal. The peak discharge is 660 lit/sec under a delivery head of 75 m. The station is controlled either manually, or automatically. The distribution network for stage I of construction is shown in Fig. 5, the layout for a single 35 hectare plot in Fig. 6, the laying of a 400 mm dia. main header of asbestos cement pipe in Fig. 7. The underground network has been dimensioned hydraulically for minimum cost. Air vents and hydraulic valves of original design were applied (Figs. 8 and 9

). Experiments are under way to replace large-diameter pipes supplying water to large areas with such made of glass-fibre reinforced polyester (Fig. 10). The diagram indicating the operational arrangement of a 35 hectare plot is shown in Table III (l=plot size, 2 = spacing of hydrants, 3 = number of laterals, 4 = equipment of one plot, 5 = spacing of nozzles, 6 = number of nozzles that can be operated simultaneously in 5 plots). Chapter 3 deals with problems of economics. According to estimates, in the farming cooperatives investment will be repayed fully within 4.49 years, while on state level the repayment period is 10.34 years. Variations in the cost of water are illustrated in Fig. 11 at three points, namely as constant costs (1), costs at the hydrant (2) and at the plant (3). PVC AS BUILDING MATERIAL By Szilágyi, L., Civ. Engr. (For the Hungarian text see pp. 345) The objective of the author, leader of the Consulting Service on the Application of Plastics in Hydraulic Engineering, is to describe the properties and potential applications of this material in sufficient detail to permit decisions to be taken by practicing engineers engaged in construction work. No details of the paper will be embarked upon here, data on this important building material, PVC, being readily available in the relevant literature of all countries engaged in major construction activity, but the method of treatment is believed to be of wider interest. Chapter 1 presents a brief review on the present and expected future world demand for plastics, Table I giving forecasts and relative magnitudes on the use of some of the more important structural materials. The present and future use of