Peter PIŠÚT

1. Channel changes of the Danube River (Slovakia) during the Little Ice Age period according to cartographic and palaeoecological evidence. Peter PIŠÚT Comenius University, Faculty of Natural Sciences, Department of Physical Geography and Geoecology, Mlynská dolina, 842 15 Bratislava 4, Slovakia

2. Middle Danube River Bratislava Celtic*dānu, meaning "to flow“; its exact equivalent is found in Welsh name of the river Donwy

3. Danube River in Slovakia • 172 km • Entrance: Devín Gate • Area of upstream basin: 131 338 km2 • Gravel-bed river • Thickness of Quaternary fluvial deposits: 8-600 m • Prior to completion of 32 dams: 600 000 m3.s-1 • River gradient: 0.043 per cent • Alpine character, flow velocity 2 m.s-1 • Mean annual discharge: 2 025 m3.s-1 • Predicted 100, 1000 and 10 000 year recurrence interval floods: 10 600, 13 000 and 15 000 m3.s-1, respectively • Largest historical discharge: 1501; 14 000 m3.s-1 (in Vienna) • Last major flow: 2002, August - 10 370 m3.s-1 (50 yr), 991 cm

4. M o r a v a D a n u b e BRATISLAVA V á h L e s s e r D a n u b e (Č a l o v) • subsiding basin, alluvial fan • Žitný Ostrov: length 90 km • area of 1 600 km2 • altitudinal difference: 27 m Ž I T N Ý O S T R O V I s l a n d Gabčíkovo WW S Z I G E T K ÖZ V á h D a n u b e M o s o n i D a n u b e KOMARNO

5. Rivers and LIA • Concept of LIA: epoch of renewed but moderate glaciation which followed the warmest part of the Holocene • Now: the period of deteriorated climatic conditions of the latter part of our millenium, approximately 1560-1860 • Possible causes: large-scale ocean-atmosphere interactions, increasinf volcanic activity, Maunder minimum of solar activity (1675-1715) • It wasn’t monotously cold, but: alternation of colder and warmer periods, drier and more humid • Geographical variability in climatic anomalies across Europe • It had already begun in 13th Century • The severest phase: 1760-1860

6. Rivers and LIA • Generally increased fluvial activity in Europe (Northern hemisphere) • Changes in fluvial regime, channel pattern • Severe winters, frozen rivers • Ice movement, ice-jam floods • More frequent high-magnitude floods in the summer season→ geomorphologically active flows and floods • Human impacts: Medieval and modern-period deforestation • Land use changes, new agro-techniques and crops (maize, potatoes, tobacco...) • Unusually high run-off

7. Interpretation of river behaviour Modern topographic maps, aerial photos... (present) Old testaments and records 15-16th C Charters 13-14th C Sketches to relatively accurate historical maps 16-19th C T. Ortvay: History of the town Bratislava (Pozsony város története), 1907-1912.

8. Anabranching and anastomosing character of the Danube planform

9. over 27 km long- 10–30 m wide S l o v a k i a A u s t r i a G e r i n n

10. Islands and abrupt channel changes: indication of historical floods

11. 1 3 9 3, November 27th. priest from Biskupice (= village on left Danube bank) raised an objection against the Stephanus, former palatinus from Rusovce (= right bank), who „quandam insulam possessionis sancte ecclesie Strigoniensis Pispuky vocate a parte fluvii Danubii habitam ad silvam et insulas dicte possessionis Pispuki per inundationes aquarum Danubii annexam Orozvar“ attached to his property on occasion of the Danube flood and along with his people cleared and destroyed local forest.

12. Cut offs triggered by floods Possession of Ostrihom archbischop (Biskupice bank) floodplain forest Rusovce bank

13. Major changes of the river network between 1380 - 1426

14. Danube between Bratislava and Komárno in 13th – 15th Century (hypothetical reconstruction) and major channel changes which occured between 1380-1426 16 km 10 km PIZIGANI´s map (1367)

15. M e d i e v a l D a n u b e - Conclusions • Study area: typical island-dominated landscape, with a similar channel pattern as known from younger periods prior to channelization (16. - 19th) with many alluvial islands, active and abandoned side channels („valleys“, „lakes“) • substantially wider active floodplain due to the existence of several meandering, parallel side channels both within the subsystem of the „Major“and „Lesser“ Danube (Čalov) • Islands: important source of intake and benefits, being used for wood production, pasture or fishing • Border disputes and forced changes of the island territories → triggered by channel changes • → such records may indicate some major floodings or shorter periods of increased lateral activity (late 1250s/early 1260s, 1300s, 1330s and 1390s) • between 1310 and 1342 – period of extremely low discharge of Čalov • between 1380 – 1426: avulsions, major changes of channel network

16. 1 5 2 8 Lazarus map

17. battle of Moháč1526 - 1683Ottoman rule

18. Anti-Ottoman fortresses protecting the access to Vienna and navigational importance of Čalov BRATISLAVA New Castler channel NEW CASTLE (1573) GÚTA ÓVÁR KOMÁRNO RÁB

19. MOSON DANUBE: 1784 Ráb (Győr) fortress 1594

20. 16th – 17th Century:Golden age of northern branch

21. ČALOV: Kolárovo (Gúta), 17th century Joined Váh and Lesser Danube today 1664

22. Komárno, an old fortress, 1595 Váh Danube Danube

24. channel width of the 16-17th Váh Danube Váh – current discharge 152 m3.s-1 700 m 440 m Danube current average discharge over 2000 m3.s-1

25. 16th century major floods • 1 5 0 1, August – the largest flood on record lasted 10 days, reconstructed discharge of 14 000 m3 (Vienna) • 1508, July, 25; August • 1516 great damage in Bratislava, Pest, Buda • 1520 – 1527 repeated floodings almost every year • 1 5 2 6, ice flood in Bratislava, 53 ember drowned • 1529, spring (in Bratislava round the clock were removing driftwood from the bridge) • 1530 - 1531 • 1535, spring – flood partly washed away Bratislava´s bridge • 1554 beluga fishing weir at Asód (Čalov branch) destroyed by ice • 1 5 5 8, June • 1 5 6 1, May • 1 5 6 3, July, around 24. (Bratislava) • 1 5 6 5, February 15. Fishermen´s bridge at Bratislava destroyed by ice • 1 5 6 6, May + July major flood (also at Rhine) • 1 5 6 8 – 1 5 6 9 – major floodings at Žitný ostrov Island • 1 5 7 0 – Komárno fortress, build in 1546 – 1557, damaged by flood • 1 5 7 2, July • 1 5 7 3, January + July 15. (Bratislava´s bridge taken away by flood) • 1 5 7 8 • 1581 – beluga fishing weir at Asód destroyed by blocked ice • 1586 – imperial army (with heavy artillery) passed through the frozen Danube • 1587, winter • 1593, July • 1595 Danube frozen at Gyor; February – March floodings; all Danube bridges except of the stony bridge in Regensburg pulled down • 1598 imperial army forced to stay on Žtný ostrov Island due to floods

26. 1520-1560 relatively favourable conditions 1560s-1590s cold, wet summers 1561-1600 bad wine harvest, slump in wine production Last third of the 16th century: climatic changes affecting price of commodities (rye, butter, honey) Increase in witch-burnings after 1560s

28. Devín´s Gate

29. map by A. E. Fritsch 1 7 7 4

30. map by A. E. Fritsch 1 7 5 3

31. 1675 17th C., latter half

32. 16th C.

33. 1712 Bratislava´s floodplain (J. J. Marinoni) Wartling channel (by avulsion around 1670)

34. 1735 section of large regular meanders Samuel Mikovíni, map of Bratislava county

35. Meandering Danube at the village of Bodíky, development of 4 meanders which were successively cut off during the 17th Century until 1752. (Reconstruction based on two A. E. Fritsch detailed maps) KRÁĽOVSKÁ LÚKA OXBOW REMNANT ORIGINAL LOCATION OF THE BODÍKY VILLAGE UNTIL 1730 SEPRÖS Elisabeth isl. Pálfi island ORIGINAL LOCATION OF THE REMETE VILLAGE