Vízügyi Közlemények, 1935 (17. évfolyam)

Kivonatok, mellékletek - Kivonat a 3. számhoz

33 The water level backed up by the ice-barrier attained a stage of 680 cm at the gauge of Mohács, so that it was lower only by 23 cm than the maximum flood recorded up to the present. The backing effect extended as far as Dombori, situated 60 kilometres upstream. The fall of the water level was 4 metres within the 22 km Mohács—Bezdán reach, 1 metre of which fell to the 13 km reach upstream from the frontier, and 3 metres to the 9 km reach downstream from the frontier. From this it could roughly be stated that the actual clogging of the river bed was in the vicinity of, or immediately downstream from the frontier. The conditions of downflow of this icy flood and the causes of formation of ice-barriers are as follows : On the 18th of February a standing ice-block between Paks and Baja broke up in consequence of mild weather, and ran down with a strong drift. Below Mohács the drifting ice came against standing ice, and blocked again. Then in the afternoon of February 19th the ice got moving along the whole length of the Hungarian Danube, and passed the frontier towards Bezdán with a strong drift at a stage of 450 cm. Upstream from Bezdán in the bend at Tovarnik the ice stopped again, and from the 19th to the 20th of February it formed a compact barrier reaching up to Mohács (fig. 4, sketch 2). On the 20th the water level was rising and the ice-barrier slipped several times, so that three ice-blocks were formed : 1. at Tovarnik, 2. at Debrina, 3. at Sirina (fig. 4, sketch 3). In the evening of the 21st the water began to subside near the frontier, which indicated that the ice-block at Tovarnik had broken up and run down, p.obably because the water had risen so high as to set the ice-block moving by its natural force. After a short while, almost at the same time, the blocks at Debrina and Sirina also began to move at 0,22—50 a. m. on the 22nd. The water stage rose to a maximum of 680 cm at Mohács, and when the ice-block had broken up, it began to subside rapidly. The causes inducing the formation of ice-barriers and icy flood are to be sought in the defects of the river bed between Mohács and Bezdán. The first and chief local factor of barrier-forming is the bend at Tovarnik in Yugoslavia, the second is a sandbank at Debrina near the Hungarian— Yugoslavien frontier, and the third is the narrow lower part of the cut-off at Sirina. Examining their effects, we find that the former two factors played a primary, and the cut-off at Sirina a secondary partin the formation of ice-barriers. The defects of the river bed upstream from the frontier came effectively into force only when the ice, packed and blocked above Batina, had been condensed. As in this deteriorated reach of the Danube ice-barrier and icy flood are to be expected to recur in the future, it will be necessary for the two States to examine and improve the river bed on common and uniform principles. 2