Technikatörténeti szemle 6. (1971-72)

KÖZLEMÉNYEK - Károlyi Zsigmond: Az Alduna szabályozás múltjából

narrows the bed is extremely deep, but on reaches where it is crossed by rock banks forcing it to spread laterally, cataracts of low depth appear over dangerous reefs with backed up water levels. Before regulation at the end of the 19 th century ships could pass this section at lower than medium stages with reduced cargo only, and not at all during low waters. These cataracts are: the Stenka (R.Sts. 1029- 1030 km), the Kozla-Dojke (R.Sts. 1013-1012 km), the Izlas-Tachtalia-Vrany (R.Sts. 1003 - 999 km), the Juc (R. Sts. 987 986 km) and finally the largest of the obstacles the Iron Gate (R. Sts. 946 — 944 km). Among the narrows the largest obstacle to navigation was the Greben: here a reef extended from the right into the channel like a groyne confining it to about 250 m width. Below it the river bed expanded without transition to a 2200 m wide bay into which the water shot down under a greet fall, causing dangerous whirlpools. Downstream, between R. Sts. 974—986 km stretches the Kazan-Pass. Here the bed is in some places hardly 150 m wide, while the water reaches a depth of 70 m. Engineering works on this section have always served the interests of navigation. The remnants of the towing-road on the right bank built by the Romans and the commemorative tablets of the road-builder emperors, have been visible until recently. The river regulation was started at the beginning of the 19 th century, when the Hungarian Water-and Construction Authority prepared an accurate map of the uncharted river section, and entrusted — on the initiative of /. Széchenyi (Fig. 1) — P. Vásárhelyi (Fig. 2) to prepare the regulation-plan of the section. (Fig. 3) Howewer, under the economic and technical conditions prevailing then, the improvement of the waterway by underwater blasting was impossible satisfactorily and therefore, besides removing the most dangerous rocks, work was confined to the construction of a 130 km long tow-way along the left bank — later called the Széchenyi-way. (Cover and Figs. 3, 13— 14) At low water this enabled the transportation of ship cargoes by road, along the critical section between Bazias and Turnu-Severin, beyond which water transport was resumed. In this way, even if very restrictedly, steam-boat traffic started as early as 1834 along the whole length of the Danube. The merits of the pioneers — I. Széchenyi and P. Vásárhelyi — were praised in the 1880 year memorial of the „Donau-Verein" of Vienna (Fig. 2) as follows: „... an enlightened and prophetical man, who recognizing the full importance of the problem, was not afraid to propose the large work of removing the obstacles of navigation, to open this important waterway to permanent traffic. This is the unquestionable and imperishable merit of the Count István Széchenyi..." „The excellent road on the right bank opposite to the former Roman tow-path, was made as the result of the efforts of Széchenyi, and it is due to him, that excellent and enthusiastic engineer Pál Vásárhelyi got the assignment to survey this section and to prepare the regulation plan." „The results of Vásárhelyi. . . his maps and depth soundings were of great use in any later work

..." „The lasting value of this work is the reliable and visual presentation of the condition prevailing at those times

..." In the second part of the 19th century several plans based on the work of P. Vásárhelyi were prepared for the regulation of this section. The Berlin Treaty of 1878 entrusted the Austro-Hungarian Monarchy to perform this work, authorizing it to levy navigation tolls to cover the expenses. The regulation works based on the plans of E.. Wallandt have been carried out in 1890— 98 on behalf of the Hungarian Goverment by an international syndicate founded for this purpose under the guidance of H

. Luther. The resident engineer in direct control was 67. Rupcsics. In the preparation of the works B. Oonda played a significant role whose monography — published in three languages — informed the international professional public about the works executed.* The individual items of the work icluded

: Blasting the Cape of the Greben, and broadening in this manner the river bed, confining the downstream reach by one of the world's longest parallel training dike between Greben and Milanovac in a length of 5,8 km; cutting over the cataracts 60 m wide canals by underwater blasting to a depth of 20 dm under the „0" level and in a total length of more than 18 km; and finally: excavate, to by-pass the roek reefs of the Iron Gate, a navigation canal of 2,2 km length into the rock along the right bank with 72 m bottom width and 30 dm depth below „0" level, and training walls on both sides, raised above the highest flood level. (Fig. 4)