Chapter 3 The Danube River Basin Nike Sommerwerk Christian Baumgartner Jurg€ Bloesch Leibniz-Institute of Freshwater Ecology and Donauauen National Park GmbH, 2304 International Association for Danube Inland Fisheries (IGB), Muggelseedamm€ Orth an der Donau, Schloss Orth, Austria Research (IAD), Stauffacherstrasse 159, 310, 12587 Berlin, Germany 8004 Zurich,€ Switzerland Eawag, Swiss Federal Institute of Aquatic Science and Technology, Uberlandstrasse€ 133, 8600 Dubendorf,€ Switzerland Thomas Hein Ana Ostojic Momir Paunovic University of Natural Resources and University of Zagreb, Faculty of Science, Institute for Biological Research, 142 Applied Life Sciences, Vienna, Institute of Division of Biology, Rooseveltov trg 6, Despota Stefana Boulevard, 11060 Hydrobiology and Aquatic Ecosystem 10000 Zagreb, Croatia Belgrade, Serbia Management, Max – Emanuelstrasse 17, 1180 Vienna, Austria WasserCluster Lunz, Dr. Carl-Kupelwieser- Prom. 5, 3293 Lunz/See, Austria Martin Schneider-Jacoby Rosi Siber Klement Tockner EuroNatur – European Nature Heritage Eawag, Swiss Federal Institute of Aquatic Leibniz-Institute of Freshwater Ecology and Fund, Konstanzer Str. 22, 78315 Radolfzell, Science and Technology, Uberlandstrasse€ Inland Fisheries (IGB), Muggelseedamm€ Germany 133, 8600 Dubendorf,€ Switzerland 310, 12587 Berlin, Germany Eawag, Swiss Federal Institute of Aquatic Science and Technology, Uberlandstrasse€ 133, 8600 Dubendorf,€ Switzerland 3.8. Human Impacts, Conservation and 3.1. Introduction Management 3.2. Historical Aspects 3.9. Major Tributaries and the Danube delta 3.3. Palaeogeography and Geology 3.9.1. Inn 3.4. Geomorphology 3.9.2. Morava 3.5. Climate and Hydrology 3.9.3. Vah 3.6. Biogeochemistry, Water Quality and Nutrients 3.9.4. Drava 3.6.1. General Characteristics 3.9.5. Tisza 3.6.2. Water Quality 3.9.6. Sava 3.7. Biodiversity 3.9.7. Velika Morava 3.7.1. Riparian Vegetation 3.9.8. Olt 3.7.2. Vegetated Islands 3.9.9. Siret 3.7.3. Macrophytes 3.9.10. Prut 3.7.4. Macroinvertebrates 3.9.11. Danube delta 3.7.5. Fish 3.10. Conclusion 3.7.6. Avifauna Acknowledgements 3.7.7. Wetland Mammals References 3.7.8. Herpetofauna Rivers of Europe Copyright Ó 2009 by Academic Press. Inc. All rights of reproduction in any form reserved. 59 60 PART | I Rivers of Europe FIGURE 3.1 Digital elevation model (upper panel) and drainage network (lower panel) of the Danube River Basin. Chapter | 3 The Danube River Basin 61 3.1. INTRODUCTION 3.2. HISTORICAL ASPECTS It was July 10 in 1648 when Pope Innocent X approved In 1908, an 11.1-cm large statuette, the so-called ‘Venus of the construction of the ‘Four-Rivers-Fountain’ at the Pi- Willendorf’, was excavated by the archaeologist Szombathy azza Navona, probably the most beautiful square in Rome. near the village of Aggsbach (Austria, Wachau valley), dat- He asked the famous sculptor Gian Lorenzo Bernini to ing back 25 000 years BC. North of this place, in Dolvi finish the fountain by 1650, a Holy Year. The four rivers Vestonica, a large meeting place of mammoth hunters from were the Nile of Africa, the Ganges of Asia, the Rio del la the same period was discovered 1924–1952. These two Plata of the Americas and the Danube of Europe (Weith- examples demonstrate that the Danube valley has experi- mann 2000). The Danube is the European river par excel- enced a long history of human occupation and cultural de- lence; a river that most effectively defines and integrates velopment that started during the Paleolithic period. Europe. It links more countries than any other river in the Between 8500 and 500 BC, permanent fishery and hunting world.TheDanubeRiverBasin(DRB)collectswaters settlements were erected in Lepinski Vir (Iron Gate Gorge) from the territories of 19 nations and it forms the inter- and Vinca (in the suburban sector of Belgrade) (Weithmann national boundaries for eight of these (Figure 3.1). The 2000). Starting >7000 years ago, farmers from Anatolia river’s largely eastward course has served as a corridor for entered Europe and expanded throughout the continent. both migration and trade, and a boundary strongly guard- The Danube was most likely one of the major expansion ed for thousands of years. The river’s name changes from pathways. There is evidence that a major flood that entered west to east from Donau, Dunaj, Duna, Dunav, Duna˘rea, the Black Sea from the Mediterranean (i.e., the diluviam) to Dunay, respectively. The names of the river (Danube, as probably forced the westward migration of these early well as Don, Dnjeper and Dnjester) most likely originate farmers. from the Persian or Celtic word Danu, which literally Between 750 and 500 BC, the Celts occupied the entire means flowing. It also may stem from the Celtic ‘Don, Upper Danube valley. The best known place was the Heune- Na,’ or ‘two rivers,’ because the Celts could not agree on burg near Riedlingen where a large Celtic wall circled the the source of the Danube (cited in Wohl in press). entire hill. The Celts respected the Danube as a bringer of life In this chapter, we provide an overview of the DRB, and death and their sole connection to the outside world. including the three main sections (Upper, Middle, Lower They called it the Great Mother of Gods – Danu. The Celts Danube), the delta and 11 major tributaries (Figures 3.1 were stimulated by Greek culture. The Greek poet Hesiod and 3.2, Table 3.1). This chapter builds upon several text- first mentioned the Danube in about 700 BC as the books on the Danube, including Liepolt (1967) and Kinzel- ‘beautifully flowing Istros’, the son of Tethys and Okeanos. bach (1994) and, among many other sources, on information Herodotus wrote in 450 BC that the (H)Istros is the largest derived from the International Commission for the Protec- river in the world, a river that ‘has its source in the country of tion of the Danube River (ICPDR). the Celts near the city Pyrene, and runs through the middle of Europe, dividing it into two portions ... before it empties itself into the Pontos Euxeinos’. During the war against the Scythes in 513/12 BC, Dareis, the great Persian king, sailed up the Danube to explore a suitable location for constructing a bridge for his army. The first European waterway was established during the Greek period and connected the Adriatic Sea with the Black Sea via the Ocra pass, the Sava River and the Lower Danube. Today, there exist plans to re-establish this ancient Danube–Adriatic waterway for navigation. The Danube was always both a migration corridor as well as a frontier. During the Roman Empire, the ‘Limes’ along the Danube as well as along the Olt River protected the Empire agains the ‘Barbarians’. The Romans erected forti- fications along the Danube such as Castra Regina (Regens- burg), Juvavum (Salzburg), Lentia (Linz), Vindobona/ Vindomana (Vienna) and Aquincum (Budapest), among many others. The Limes played an important role even long after the fall of the Roman Empire, for example, it was used as a fortification against the Mongolian invasion in 1241. The armies of Charlemagne also marched along the rem- FIGURE 3.2 Longitudinal profile of the Danube River and its major nants of the Roman Limes, as did the Crusaders. The bound- ary between Orient and Occident is roughly just east of the 62 TABLE 3.1 General characterization of the Danube River Basin Upper Middle Lower Delta Inn Morava Vah Drava Tisza Sava Velika Iskar Olt Siret Prut Danube Danube Danube Danube Morava Mean catchment 793 435 355 9 1260 378 473 760 350 541 631 655 621 485 267 elevation (m) Catchment area (km2) 104 932 473 214 218 387 4560 26 128 27 267 19 660 40 087 156 087 95 793 37 571 8860 24 439 46 289 28 568 Mean annual 25.3 125.9 188 205 23.1 3.47 4.35 17.1 25.0 49.6 8.74 1.70 5.43 6.63 2.11 discharge (km3) Mean annual 101.2 79.2 60.5 43.2 136.0 63.8 79.3 112.1 65.8 105.4 77.8 62.1 67.6 62.4 59.8 precipitation (cm) Mean air temperature (C) 6.7 8.8 9.2 10.7 4.6 8.1 7.5 7.3 8.6 9.2 9.3 9.4 7.9 7.7 8.5 Number of ecological 4 8712423 2432454 regions Dominant (25%) 2; 70 52 9 55 2; 70 52; 70 13; 52 2; 52 52 27; 52 9 9; 58 9; 13 13; 22 13; 22; 28 ecological region(s) Land use (% of catchment) Urban 4.7 4.1 6.0 2.4 2.9 6.0 6.4 3.5 4.9 2.1 1.7 6.3 5.0 7.7 4.9 Arable 31.5 44.8 54.1 22.9 14.7 59.4 45.6 28.7 48.1 36.9 38.8 42.2 36.5 38.8 57.3 Pasture 13.4 7.8 6.7 1.1 15.4 3.0 6.4 7.9 11.1 5.8 7.3 4.3 12.6 9.4 7.3 Forest 37.3 35.4 26.6 5.8 35.2 29.3 36.8 45.8 30.0 45.3 42.6 30.3 37.4 38.2 27.7 Natural grassland 6.4 5.9 4.1 4.6 13.5 1.8 3.8 9.0 4.4 8.4 8.8 14.6 6.7 3.9 0.6 Sparse vegetation 5.5 0.6 0.3 1.4 17.0 0.0 0.2 3.9 0.1 0.7 0.5 1.6 0.4 0.2 0.0 Wetland 0.3 0.5 0.7 49.0 0.3 0.0 0.2 0.3 0.7 0.1 0.0 0.1 0.4 0.5 1.2 Freshwaterbodies 0.9 0.9 1.5 12.8 1.0 0.5 0.6 0.9 0.7 0.7 0.3 0.6 1.0 1.3 1.0 Protected area 0.5 2.8 0.7 89.1 0.9 7.7 11.2 0.3 3.0 0.8 0.0 0.0 0.0 0.3 3.3 (% of catchment) Water stress (1–3) 1995 2.0 2.0 2.0 2.2 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.1 2.0 2.0 2.0 2070 2.9 3.0 3.0 3.0 2.9 3.0 3.0 3.0 3.0 2.9 2.9 3.0 3.0 3.0 3.0 Fragmentation (1–3) 3 3 2 1 3 3 3 3 2 2 2 2 3 3 2 Number of large 217 143 227 0 31 46 17 49 45 18 3 2 27 18 3 dams (>15 m) Native fish species 59 72 70 70 15 45 37 49 56 50 35 37 17 29 41 Nonnative fish species 13 12 7 4 2 7 n.d.