A Veszprém Megyei Múzeumok Közleményei 7. (Veszprém, 1968)

Sági Károly: A Balaton vízállástendenciái 1863-ig a történeti és kartográfiai adatok tükrében

water-level height of 105,25 m above the Adriatic Sea for the time of preparation of KRIEGER's map. Had the Lake's water-level at KRIEGER's mapping time been in fact 109,8 m high, Máriaasszony-sziget would have been covered by water waves. Already KRIEGER's contemporaries had been wary of his designs and another authority in the field of technology, H. TUMLER, openly objected the determinations of level carried out by KRIEGER. Athough BENDEFY had calculated on the basis of TUMLER'

s data a water-level height of 106,07 m above the Adriatic Sea for 1803, he considers TUMLER's data as „groundless". On the basis of a map drawn in 180-5 (fig. 9) which is kept in the Festetics Archive the waterlevel of the Balaton above the Adriatic should be 105 m high. TUMLER had been engaged in Balatonresearch in 1803 and, on the basis of BENDEï'Y's above mentioned reconstruction, he found the height to be 106,07 m. The difference between the latter two results is only 1,07 in. According to BENDEFY the 0-division of the contemporary Breda hydrometer watergauge is at the height of 96,63 m above the level of the Adriatic Sea. According to a recent calculation of D. PAVEL the same 0-division should be considered to be at a hight of 95,65 m. above the Adriatic. By substituting this value in BENDEFY's calculations TUMLER's waterlevel height will come to 105,09 m above the Adriatic, a result that surprisingly agrees with the 1805 state of facts. J. BESZÉDES mentions two Balaton water-levels in connection with the length-section of the Sió-Valley, the first one indicating the situation prior to Octiber 24, 1818, the second one that on July 30, 1828. In the section made by BESZÉDES the upmost ripple mark of the lake-shore is indicating a situation in general identical with today's situation. On this basis the water-level prior to October 24, 1818 can be considered to have been 106,21 m and the water-level on July 30, 1828 104,4 m high above the Adriatic Sea. According to a hand-written record of Vörs dating from 1821 the water in the grove stood so high in that year that the hay was carried out from Halászok szigete (= Fishers' Island) in an axle-deep water. The place of Halászok szigete is marked in the map drawn by M. SZALÓS (fig. 14). From a confromtation of this map with the contour-lined map of the surroundings (fig. 3) the boundary-line of the island turns out to be the contour-line 105— 105,25. The water-level at the time of the 1821 haymaking must have been by 50 cm higher. According to the results of J. BESZÉDES the Balaton's water-level fell by 4 feet in 1822 and must have been at that time at a height between 104,49 m above the Adriatic Sea. In 1833, according to the map of J. BESZÉDES the Keszthely-part of which is show in diagram 12, the Balatons water-level was 105 m above the level of the Adriatic. Due to the great drought, the water-level fell by 4 feet in 1834 to a height of 103,74 m above the level of the Adriatic. At the time of the memorable drought between the years 1834 and 1837 was built the bridge at Fenékpuszta which, according to the cadastral map of the year 1858 had a length of 47 fathoms, i. e. 89,11 m. In a more recent Sió-section (fig. 13) prepared by J. BESZÉDES the Balaton's water-level relative to June 10, 1842 is shown. The survey-level at the road running along the crest of the ripple marks lay by 2'11" higher corresponding to a height of 107,47 — 0,91 m. On the recorded day the Balaton's water-level was exactly 10 feet lower, corresponding to a height of 105,22 m above the level of the Adriatic. According to a record put down by M. TÖRÖK on June 11, 1842 the piles of the Fenékpuszta-Bridge stood out of water by 5 feet and 9 inches. Following this reasoning the height of the bridge-crown must have been 107,05 m above the level of the Adriatic. According to the above mentioned cadastral map of 1858 the Balaton's water-level was 104,55 rn above the level of the Adriatic. In 1859, according to the map of M. SZALÓS (fig. 14) the Balaton's water-level was 105,25 m above the Adriatic. In 1860 and 1861, according to CHOLNOKY, the water-level of the Lake rose to a height of 105,15 m above the Adriatic and by the inundation the embankments of the Southern Railway under construction had been damaged in several places. This railway line was opened to traffic on March 22, 1861.Great damages were caused by the driftice driven upon the railway by the strong northwind in 1862. The Southern Railway Company began soliciting the regulation of the Balaton as a result of which the plans and budget for the regulation had been voted in the summer of 1862. Work was started immediately and the Sió-Canal was opened with all solemnity on October 25, 1863. From this time on there have been regular water-level-readings on the water-gauges placed at Siófok and later at other places of the Balaton. Károly Sági 466