Vízügyi Közlemények, 1935 (17. évfolyam)

Kivonatok, mellékletek - Kivonat a 4. számhoz

22 to offer a simple solution. Another proposal was to lead all waters into an abandoned river-bend below Szeged, whence, at low stages, they would flow freely by gravitation, at high stages, they could be lifted by pumping into the Tisza river. The latter proposal seemed to be open to objection from the economic point of view, while the former was rendered impracticable by the circumstance that the outlet of the border-canal would have been beyond the Trianon-frontier at present limiting Yougoslavian territory. (In figure 2 the new frontier is shown by a clotted line.) Figure 3 represents the general design of the solution that has been accepted. This plan also comprises the territory of two other flood-control companies upstream of Szeged, with the adjacent areas yielding outland water. The water from area I. (about 130,000 hectares) will be drained by the ,,Dong-ér" canal, which opens freely into the Tisza river even at the highest stage. The water of system II will be gathered by the ,,Algyő" canal, which opens freely into the Tisza river up to a stage of -f- 6-20 metres, while at higher stages lasting 6—8 weeks and even more, a suitable storage of the water has to be provided. The water of system III will be carried into the Tisza by the pumping plant at Ludvár, whose capacity is 3-0 cu metres per second, and the connected sluice, both already existing. This design, as a solution of constraint does not offer ideal drainage system, either from the point of view of economy or of security ; in regard, however, to the compulsory application of water-storage, it sets an interesting and remarkable problem in water-economy. The first step towards regulating the waters of systems II and III (fig. 5) has been taken within the last few years, when the company constructed the Algyő canal, which leads to the Tisza river, with a length of 18 Km. In the upper part of figure 6 the proposed, and in the lower part the executed longitudinal section of the canal are to be seen. The construction costs amounted to 700,000 pengő. The system of side canals has not yet been carried out. Considering the sandy soil of the drained areas, a runoff of 0-1 litre per second per hectare has been provided for. The canal runs between levees across the protected area ; its middle reach crosses the pond of Fehértó, a flat basin of alkali soil, which in its original state is able to store about 6 million cu. metres of water. Figure 7 shows the kind of soils in the northern part of the protected area. Dotted surface : old-alluvial sand ; surface striped horizontally : new-alluvial clayey soil ; white surface : diluvial loess ; the others are watery and alkali soils. The outland water running off towards the protected area partly on the surface, partly in the soil, contains a large amount of dissolved sodium salts, especially sodium carbonate. Naturally, this water, coming to a stillstand in deep lowlands and evaporating thence, caused the formation of alkali soils. The regulation of waters put a stop to further formation of these soils. As an attempt to improve alkali soils in connection with their utilisation, the City of Szeged has established an artificial fish-pond of 550 hectares in the southern part of the Fehértó mentioned above (fig. 8 and 9). In order to obtain a depth of 1-0—1-2 m required for pisciculture, the basins of the fish-ponds have been surrounded with dams. The supply of the fish pond with water is a matter of some difficulty, for sufficient quantity of water are very rarely available. For filling up the basins, the flood water of the Tisza river in