The Danubian Crocodile That Died Young

MAGYARUL

Correction! 

In our article published on the Danubian Islands blog on 10 June 2024 (Island in the Sea of Nettles), we falsely claimed that the name of the Danubian island at the foot of the Felső-Öreghegy hill in Dunaföldvár, Hungary was the Felső-Öreghegyi Island. On the contrary, the reality is that the geographical name Krokodil Island is shown on a Danube site plan from 1910. We apologise to all our readers and will henceforth use the name Crocodile Island as a word of honour, because it is much cooler.  

A crocodile and a loess hill combined on a postcard from Dunaföldvár.

For our readers used to TikTok videos, to recap: the Felső-Öreghegy Island Crocodile Island in Dunaföldvár first appeared as a sandbar on a map in 1850, after less than four decades it was connected to the right bank by a cross dyke, after which a massive sedimentation started, which resulted in the Crocodile being quite difficult to approach today. Our readers, who are used to longer texts are warmly welcome to continue with the next paragraph:  

The Crocodile Island and the cross dyke beneath the barren loess hills

At Dunaföldvár, the Danube cuts sharply into the right bank, gradually destroying the loess hill called Öreghegy (Old Mountain). Over time, erosion caused this hill to split into two parts, the Upper and Lower Öreghegy, and Dunaföldvár was able to settle in the valley between the two. The erosive impact of the Danube is well illustrated by the steep loess walls of the height and steepness of the castle walls, although most of these are obscured by the recent growth of floodplain forest.  

Crocodile Island was first depicted as an unnamed sandbar on 12 May 1850. It is possible, of course, that an even older map will come to light, but what is certain is that the earliest maps from the 1850s to the 1860s all depicted it as a long, narrow sandbar, whether they were maps showing the location of ship mills, the situation of the riverbed or maps of 19th century land use. The northern tip of the sandbar stretched from the westernmost point of the Danube for almost a kilometre to the church of St. Ilona in Dunaföldvárr. In addition, there was a lower sandbar in the middle of the Danube at Dunaföldvár, roughly in the section of the present day Beszédes József bridge, which was later dredged away because it was an obstacle to navigation.

12 May 1850. The ship mills and the sandbars are both important features of the Danubian maps near Dunaföldvár. (source) 

Crocodile Island was first depicted as a sandbar in 1910, but the geographical name appeared in the local press earlier, in 1889, and was associated with mostly wildly fictious stories. It was first mentioned in the Szekszárd Vidéke periodical, but the esoteric article published here reveals little of the island's history other than the geographical name, and the fact that the island was already known by that name:

"There is also talk of a witches' castle near the shipyard, in the vicinity of the Crocodile Island in the Danube. Here, on quiet summer nights, children's cries can be heard and occasionally flames rise from the water. Next time Pepi Etl will bring along a heart-strengthening spirit from Szekszárd, as he intends to blow it up..." (source) 

Ten years later, the death of a tinker's lad adds to our hydrological knowledge of the curiously named island: 

Vilmos Szavalovics, a 26-year-old tinker, fell victim to an unwise act of recklessness in the town of Dunaföldvar. Although he and several of his companions went swimming in the Danube in a rather drunken state, and although he was not a good swimmer, he took to the water in the most shallow part of the Danube to reach the so-called "Crocodile" island. But he paid for his courage with his life, for he was swept away by the tide and buried by the waves before help arrived. His body was recovered on 27 July [1899] in Dunaföldvár. (source) 

1910. The only mention of the Crocodile Island on a map

From the description it is likely that in the summer of 1899 the T-shaped embankment on the island had not yet been completed, as the tinker apprentice would obviously not have chosen to swim, even when drunk, if it is possible to walk onto the island on dry feet through a stone dam. We also learn that at this time the drift line was still at the base of the loess walls, making it very difficult for those attempting to swim along the shore of the island. But the most surreal account of the island was published in 1911, when it was last mentioned in written form as 'Crocodile':

Crocodile in the Danube. This somewhat unbelievable news is reported from Dunaföldvár: the employees of the timber merchant Sándor Schvarcz were busy removing sleepers from the Danube when a huge crocodile emerged from the plank. At first the workers were frightened by the teeth-gnashing reptile, but when the restless crocodile lunged at them, they beat it to death with their axes. Interestingly, in this very part of the Danube where the crocodile adventure took place, there is an island that has been called 'Crocodile Island' for years. It is thought likely that the dangerous reptile escaped from a transport of animals that had recently passed through the area. (source) 

The case of the tragically extinct crocodile, if it happened years earlier, might explain the strange name of the island of Dunaföldvár, but in that order it is a very astonishing story, the like of which we have never even read before. Subsequently, the geographical name 'Krokodil' disappears from sources and maps alike. 

1930. An island is growing on both sides of the "T"-shaped dyke 

At the time of the "Crocodile Incident", there was already a T-shaped dyke connecting the island to the right river bank, which soon sealed the fate of the island, but prevented further lateral erosion of the Upper Öreghegy. The drift line of the river was moved away from the already thoroughly undercut loess slopes and the bed, narrowed by the stone dyke, began to deepen. In 1930, the cross-dam appeared to have forced the water of the tributary back into the main branch partly through the reef, resulting in the splitting of Crocodile Island. At this time, the entire island must have been about 400 metres long.

 28th September 1959. 

At the low water level of 181 centimetres measured in Budapest on 28 September 1959, the riverbed formations whose reforestation is currently defining the island's appearance are already visible. The shallow sandbar formation starting at the northern tip and the filling below the cross-dam can be observed. On the aerial photograph, the island is still divided into two distinct parts, a similar situation as a few years later on the map of the Danube, the only map other than the 1910 map to include any name for the island. 

The upper and lower sandbars around 1963.

This map of the Danube must have been made sometime in the first half of the 1960s. It provides detailed information on the state of the Danube at that time and is the first to show the island in the form of an ice-cream broken in half. The handle is the Lower sandbar and the core of the ice-cream is the Upper sandbar. Blue crescents mark the mostly water-covered bar formed in the riverbed opposite the 1562 river kilometre marker. The shape depicted on the map does not in the least resemble a naturally formed island.

15th September 1966.

Although the T-shaped dyke was marked on the 1930 map, the river regulation structure was probably covered by the Danube even at medium water levels, as shown on the 1966 aerial photograph. The river fills the bed up to the base of the loess walls, just as it did before the regulation. The Hungarian Hydroinfo archive records a water level of 385 centimetres in Budapest at the time, and there is nothing between the island and the shore to break the grey monotony of the water surface, just as the barren monotony of the island is punctuated by a few trees. 

The forested Crocodile island in 2005. 

Comparing the situation in 1966 with the present situation, the expansion of vegetation is striking. This process has occurred in a similar way almost everywhere along the Hungarian stretch of the Danube: the lowering of the riverbed due to river regulation has led to the drying up of certain riparian areas, allowing vegetation to establish and succession to take place. This was no different in the area of Dunaföldvár, where one of the largest river bed subsidence events in Hungary took place. Since the process is irreversible, just as the crocodile that was beaten to death could not have been brought back to life by the dock workers in 1911, it is unlikely that Crocodile Island will ever be a real Danube island again, as it never really was. But this is not necessarily a problem, as the sea of nettles that has grown up on the floodplain preserves a Danube jewel box of unique natural value.

Preferably for a long time to come. 

Translated with DeepL.com (free version)

Island in the Sea of Nettles

 

MAGYARUL

In summer, the defence mechanisms of the Danube islands are activated. The wildlife puts the most beautiful floodplain landscapes under strict protection, drawing a smokescreen of insects, spiders and bloodsuckers, installing mine barriers of impenetrable soot and blackberry bark, forming barbed wire barriers of man-high nettles, and if all this were not enough, the flooding due to heavy rainfall overwhelms the remaining paths in the riverine forests. Even the best armour, long-sleeved shirts, thick trousers, hats, mosquito repellent and rubber boots won't help, there are simply some islands where access through ditches and bushes is impossible. One such place is the former sand bar at the foot of the loess wall in Dunaföldvár, which has been given its own name, Felső-Öreghegyi Island. 

In Dunaföldvár, the Felső-Öreghegy is a loess hill, which is thoroughly dug into by the Danube from the east. The middle section of the ridge is missing from the NNE-SSE line of hills, which is the  characteristic tectonic direction of the Transdanubian Mezőség plains, and therefore it breaks off with a steep slope towards the Danube, which is also characteristic of the eastern border of the Mezőség. The inner curve of this bend formed a sand bar, which soon became an island as a result of the subsidence of the average river level due to river regulation, the construction of a cross barrier prevented further erosion of the bank, but this ultimately meant that the island is now unrecognisable from the bank, from the main branch and even from the József Beszédes bridge. The same can be said of the huge Felső Island of Dunaföldvár on the left bank, which is adjacent to the half-broken ice-cream-shaped Felső-Öreghegyi Island at river kilometer 1562. 

This strange shape is due to the fact that the island's part south of the cross dam is a stone dyke, while the upper part widens considerably at the expense of the tributary. The name tributary is an exaggeration, as the former riverbed is divided into two sub-basins, or oxbow lakes, of which the northern one is the larger, longer and has the larger open water surface. On the morning of 2 June 2024, at a water level of 107 centimetres at Dunaföldvár gauge at the time of rising water level, there was no connection between the two sub-basins, but it was not long before the water broke through the unrecognisable cross-barrier, which was particularly difficult to find because of the circumstances described in the first paragraph. Its position could be determined by the crop stones that had emerged in a wild boar's pit at the foot of the riverbank, which in many places is steep as a castle wall, but the soil had almost completely buried it. Traces of rainfall destroying the loess wall could be observed in several places, with the material deposited almost immediately entering the tributary, constantly filling it.

The unseen Felső-Öreghegyi Island seen from the top of the Dunaföldvár loess wall.

The southern tip of the island, at rising water level.

The oxbow lake surrounded by the sea of nettles.

View of the cross dam, buried and overgrown beyond recognition.

The steadily rising water level is submerging the riparian vegetation.

Remnants of the cross dam near the loess wall.

The open water surface of the upper lake.

Still life with nettles.

View from the cross dam towards north.

At this water level, the cross dam is the only possible way to enter the island, but the man-high nettle forms an impenetrable barrier on the island's steep slopes, effectively preventing more detailed documentation of the island. The presence of the large nettle is an indicator of the abundant nitrogen content of the soil, both on the island and in the riverine forest, and has even obliterated the path leading to the island. It is therefore definitely worth returning here at lower water levels, well away from the growing season. 

Translated with DeepL.com (free version)

Bridgeman on the roof in Regensburg

MAGYARUL

The stone bridge of Regensburg is the oldest crossing on the Danube, and the second permanent crossing on the Danube, besides Emperor Trajan's old bridge at Turnu Severin. Its eventful history of nearly nine centuries is full of legends, the most famous of which is the rivalry between the builders of the bridge and the cathedral, which is usually linked to the statue of Bruckmandl on the bridge. This legend probably originated later, the meaning of the statue, like many other figurative representations of the bridge, having been lost centuries ago. Indeed, the statue we see today does not even resemble the version that was damaged earlier. 

The oldest illustration of the Bruckmandl (Georg Hufnagel, 1594. source)

It's quite a coincidence that the statue, known by its many names (Brücken-Männlein, Bruckmandl, Brückenmännchen), still stands on the bridge, defying the centuries. Other similar decorative elements have long since disappeared, collapsed, worn away, dismantled, but the young man with curly hair, sitting on the saddle roof and dressed in a swimming gown, has been restored each time and is still the most photographed work of art by tourists in Regensburg. 

The renovated statue on the stone bridge in Regensburg.

One can only guess who, when and why decided to build this statue. What is certain is that it was placed in its present location after the stone bridge was completed. Regensburg was already an important river crossing before the foundation of the Roman fort Castra Regina in 179 AD, despite the fact that it is a relatively wide stretch of river, dotted with gravel banks and islands. At times, a pontoon bridge could have provided a temporary crossing between the province of Raetia and the Germanic territories, and later between the northern and southern Germanic territories. We have already discussed the changes in the riverbed of the Danube at Regensburg, where we have already described the different conditions prevailing in the riverbed at the time the bridge was built. Presumably, after considerable preparations, such as the accumulation of wood and stone building materials, money and royal approval, work on the riverbed could have begun in the year of our Lord 1135, in an extremely dry, droughty summer, marked by extreme low-water on the Danube, with the foundation of the stone piers.

It took 11 years to build the bridge, opening to the public in 1146, and was hailed as one of the architectural wonders of Europe even at the time of its completion. It is no coincidence that the legend of its construction includes the devil, since it was not at all a natural phenomenon to walk across such a large river, even in the upper, German section, with dry feet in the Middle Ages. The stone bridge was built of sandstone, originally with sixteen piers covering 1/3 of the entire cross-section of the riverbed, which still has a relatively serious backwater effect on the Danube. In the meantime, the bridge has been slightly shortened, with a northern and a southern pier built into the bank. Over the centuries, the piers have been continuously widened by piles and stone deposits, mainly to protect against icy floods. Over time, these piers grew so large that various workshops were built on them, harnessing the energy of the Danube swollen by the bridge piers.

The long gone old towers of the stone bridge (Matthäus Merian)

The decorations and superstructures of the Regensburg stone bridge underlined the political, strategic and economic importance of the structure, as it was much more than a river crossing. Not only did the stone bridge represent the power and wealth of the imperial city to passing merchants, ambassadors and armies, but its construction further enhanced the city's power and wealth by focusing north-south transit traffic to Regensburg. The most striking of the structures were undoubtedly the gate towers. These restricted and controlled the flow of traffic through the city. There were originally three of them, one in the north at Stadtamhof, one at Regensburg (still standing) and one in the middle of the river, on the administrative border between the two towns, roughly where you could get down to the island of Oberer Wöhrd, which belonged to Regensburg. It was this tower that was the first to be destroyed when the city was hit by severe flooding in 1784. The Black Tower of Stadtamhof was damaged during the Napoleonic Wars, when there was heavy fighting on the bridge, and had to be demolished in 1809. 

But medieval travellers would find it difficult to recognise the bridge as we know it today. Over its nearly nine centuries of history, the bridge has gradually lost its decorative elements, its towers and statues, like a Christmas tree that is slowly taken down after the Epiphany. The difference is that the "Christmas tree" in Regensburg has got back a decoration, the Brückmännchen. Some of the ornaments on the bridge are well known, some have been saved in the city museum, while others have been lost forever. 

The third Bruckmandl on a postcard (wikipedia)

There was a basilisk relief on the bridge, on the 10th pillar from the south, on the downstream side, which kept away evil spirits. By this is not meant demons specifically, but e.g. floods and ice and similar harms that threatened the existence of the bridge (=the wealth of the city). Next to it, on the 9th pillar, a weasel was depicted, which, interestingly enough, was able to keep the basilisk in check. This relief, however, had worn off by 1835. Opposite the present statue of the Bruckmandl there was a relief of two fighting roosters, which had a biblical meaning of light and vigilance, but also a secular meaning, perhaps more representative of everyday life in Regensburg: the political struggle between the imperial city of Regensburg and the Duchy of Bavaria, which was separated by the bridge. A statue of a lion, which had lost its head by 1821, stood above the 10th bridge deck from the south. The rest disappeared around 1916/1917. There was also a reclining lion relief on the bridge above pier 11, probably the coat of arms of Emperor Conrad Hohenstaufen. This section of the bridge was blown up by German troops in April 1945, but fortunately it was recovered from the river by divers in 1952 and is now in the city museum. The bridge also featured the coat of arms of the town, the two crossed keys.

Compared to these ornamental elements, the Bruckmandl is a particularly new monument, having spent less than 170 years of its nearly nine-century history in its current location, at the highest point of the bridge, built into its western parapet. The figure himself sits astride the saddle of a superstructure on a massive column, his hands raised to his eyes, looking south towards the cathedral as if to shield his eyes from the scorching sun. This statue was erected on its present site on 23 April 1854, designed by the architect Michael Maurerer, the figure sitting on the roof is the work of the sculptor Anton Blank and has little or nothing to do with the earlier Bruckmandl, to which urban legends are linked.

The city museum has a sandstone sculpture torso with missing arms and legs and a head perched precariously on its neck. It depicts a young man dressed in a loincloth that could pass for a bathing suit. His head is covered with shoulder-length curls, and there are teeth in his half-open mouth. His upper body is turned to the left as he sits on a saddle roof, while a ribbon on the roof is engraved with the Gothic inscription []chuk wie heiß. The front of the inscription is worn away, and the initial letter is presumably an "S". 

Workshops attached to the bridge's piers, the Bruckmandl sits behind the second from the left (source)

The Bruckmandl originally sat on top of the gateway to a hydro-powered grinding mill near the 3rd pier on the east side of the bridge (see initial image) until 1791. By then the plank workshop was gone, and the tower in the middle of the bridge had already been knocked down by the flood of 1784. In 1791, a toll house was built on the site of the tower, which fortunately also had a saddle roof, so the statue was given a new roof to continue looking out over. In 1809 he lost his hands and legs in the Napoleonic wars. Local historiography is typically silent on the fact that most of the damage in Regensburg was probably caused by Bavarian troops allied with Napoleon as they tried to drive the Austrians out of the city. The statue, which must have become unstable during the battle, was knocked onto the bridge by a spring storm in 1817, when the head of the statue broke off. Temporarily repaired, the statue was re-installed on the roof of the tollhouse for a few years, where it continued to withstand the elements until 1826, when the tollhouse was demolished. The Bruckmandl's torso was first taken to the antiquities collection in the cloisters of the cathedral, from there to the Historical Society's collection at the Ulrich Church and then to the city museum. In 1849, on local initiative, a completely new statue was erected in a completely new location, at the highest point of the stone bridge.    

The earliest pictorial representation of the Bruckmandl dates from 1594, Georg Hufnagel's sketch for copper engreving depicts the city of Regensburg from the hills above the Stadtamhof, with a separate enlarged image of the Bruckmandl in the lower left corner. There is a stone gateway with a saddle roof on top. As the structure was part of the eastern parapet of the bridge, the bridgehead faces south, which is the same as the torso in the museum. The inscription 'Schiuck wie hais' is inscribed on the ribbon next to its right leg. However, it is quite certain that this sculpture is not original. This is confirmed by the inscription on the gate: RENOVIERT ANNO 1579, above which is the coat of arms of Regensburg and a date of 1446, presumably the date of construction of the gate, which may have been damaged together with the statue in the fire of 1555.    

Several theories have tried to explain the meaning of Bruckmandl. Some simply saw it as an advertisement for a nearby bath. Such a baths existed in Regensburg, but it is unlikely that the bridge's owner would have allowed such an advertisement to be erected, at least no similar analogy is known. A somewhat more reasonable astronomical theory is that the statue is a direction indicator, an 'angel of the south', showing travellers the direction of south with its dress, its gaze and its hands covering the eyes. This may have been necessary because the stone bridge did not exactly follow the north-south axis, with the northern part of the bridge deviating eastwards and the southern part westwards from the imaginary line. The third theory is relatively modern, and it is about the rivalry between the master mason of the dome and the master builder of the bridge. It is no wonder that the bridge builder won the competition: the construction of the St Peter's Cathedral in Regensburg has begun 127 years after the bridge was opened and was not completed until 1872, when the two towers were also completed in Gothic style.   

Along with the statue, the mysterious inscription has captured the imagination of many people. Some thought that it might refer to the heat and drought that ravaged the area when the bridge was built, but there was also an urban Jewish legend that it was the first words of a mute child thrown into the Danube instead of a fire. A note from a nearby monastery, however, has led to the discovery of a complete version of the text, but it has not been of much help to researchers:

Schuh wie haiß / zu Regensburg seyn dy Heuter feist

The text presumably captures a joke of the time, but its meaning has been lost in the past. At the time of its construction it was understood by everyone, but over time the meaning has faded, but it is similar to the Hungarian saying 'A dead frog croaks on the wet shore of a dry lake': 'It is so hot that I'm freezing,  the horses in Regensburg are so skinny that they are binging'. 

The third version of the Bruckmandl has been restored in 2012-2018 for the last time (source)

There must have been a logical connection between the sculpture and the text, leading many to believe that the saddle roof could represent the skinny horses of Regensburg, although it is likely that in this case there is a much more complex story behind the story. 

Translated with DeepL.com (free version)

Literature:

• Karl Bauer: Regensburg. Kunst-Kultur- und Alltagsgeschichte. Buchverlag 2014. 6. kiadás
• https://www.regensburg.de/kultur/kulturdatenbank/eintrag/118949
• https://www.regensburger-tagebuch.de/2013/01/das-regensburger-bruckmandl-teil-2.html
• https://www.regensburger-tagebuch.de/2013/01/das-regensburger-bruckmandl.html#more
• https://www.bernd-nebel.de/bruecken/index.html?/bruecken/3_bedeutend/regensburg/regensburg.html

The Castle in the Middle of the Danube

 MAGYARUL

Spielberg castle on the Danube / Litography of Jacob Alt

It's not necessarily the Inség (Hunger) stone at Budapest that comes to mind when talking about rocky islands on the Danube, but rather the Babakai cliff on the Lower-Danube, or Jochenstein on the German-Austrian border. There were also island forts on the Danube, Ada Kaleh was perhaps the finest example, with its ramparts and bastions almost occupying the entire island on which it was built, until it was sunk by the "progression". However, there is another island in the Danube that fulfils both criteria, a rocky promontory and a castle, built in the middle of the Danube. Today, Spielberg's castle is a little difficult to find; it has been moved from the middle of the Danube by river regulation and is hidden in the middle of a riverine forest on the left bank of the Danube at river km 2116, opposite to the town of Enns in Austria.

 Ruins of Spielberg in 1840. (W. Mossman, W.H. Bartlett)

Spielberg castle on Matthias Vischer's engraving, 1674 (source)

Spielberg castle in 1650., sr. Matthäus Merian's engraving (source)

Without the river regulation works, it could be a true castle for hydrologers, ideal for landlords exploring the Danube, as an icebreaker fixed point in the middle of the ever-changing floodplain archipelago between Linz and Mauthausen. On the slower-flowing stretch behind the granite cliff jutting out of the riverbed, gravel bars, sandbanks and islands have formed and transformed after each flood, taking on a new shape. The Danube's turbulent, swirling course over the smaller reefs made navigation in the northern tributary difficult, as did the construction of the castle. 

Originally, Spielberg's granite cliff may have been closer to the right bank of the Danube, as evidenced by the Roman archaeological atrifacts found on it. The legionary camp of LAURIACUM at the mouth of the river Enns, where the veteran Roman soldier St Florian was pushed off the bridge with a millstone around his neck, was situated opposite. The discovery of Roman relics is no less sad a story, as the 1940/41 excavation season was carried out by prisoners from the Gusen concentration camp, a part of the Mauthausen Lager. Prior to that, in the 1930s, in keeping with the spirit of the times, the courtyard of the ruin had been the site of so-called knightly ceremonies held by local Nazis.

The Enns estuary and Spielberg Castle in the middle of the river (drawn by Charles de Feignet)

Spielberg Castle is almost a thousand years old, the earliest part of it dating back to the first decades of the 12th century. It was probably already on an island in the Danube when it was built, as its owners used it primarily as a castle of refuge rather than a residence. In times of war, this impregnable fortress was used by its lords as a refuge for their families, treasures and other valuables. Perhaps that is why its owners treated it like a hot potato, its first half-millennium of history being one of constant changes of ownership. It has been privately owned, owned by ruling families, the Babenbergs, the Habsburgs, and has been owned by various ecclesiastical estates, of which Regensburg was perhaps the most distant, with St Florian's monastery the closest. In 1619 it was a Danube toll-house, but the inhabitants of the castle were fond of plundering Danube sailors shipwrecked on the granite cliffs. Interestingly, the destruction of the castle was not due to siege, fire or frequent changes of ownership, but to the neglect of the longest-standing Weissenwolff family, who owned the castle and later its ruins until 1961. 

The oldest part of the castle is the late Romanesque tower, originally five storeys high, which was added two storeys higher in the early 1500s when the outer castle wall was built. The age of the engravings in the entry can also be determined from the collapsed roof structure in 1840. The best preserved part of the castle is the outer castle. A forester still lives here and carries out basic maintenance work.

The castle on the 1st military survey (1773-1781)

The castle on the 2nd military survey (1809-1818)

The castle on the 3rd military survey (1869-1887)

Parallel to the gradual destruction of the castle in the 18th century, a process was taking place in the Danube riverbed that was slowly removing the castle from the middle of the river. The main riverbed was shifted by the development of the bends to the Enghageni branch, south of the castle, and the 19th century river regulation preserved this situation, which was made worse by the construction of the hydroelectrical power plant between Abwinden and Asten, where the floodplain forest that was home to Spielberg Castle was located directly below the dam, and the drying out of the river had a major impact. The small tributaries forming the archipelago were filled up and the forest covering the different levels of geomorphology grew on the alluvium. To complete this process, Spielberg Castle was officially transferred administratively from Enns to Langenstein on the left bank on 1 January 1997. Spielberg Castle is still privately owned and a local NGO was established in 2013 to maintain and preserve it.

Spielberg castle as it seen today, south from the Gusen bridge (Google)

However, even if they succeed in restoring the castle, the Danube is unlikely to be diverted back to the lonely granite cliff, so the floodplain castle will not again become a unique hydrological curiosity; an island castle on the Danube. 

Translated with DeepL.com (free version)

The Rise and Fall of the Vienna Archipelago (1529-2010)

Cutting the Gordian Danube, Vienna 1875. (source)

IN HUNGARIAN

My absolute favourite book of 2023 was Wasser | Stadt | Wien. 458 pages of solid hydrology about Vienna, much of it of course about the Danube. The volume also includes nine full-page pictures of the changes in the river meanders around the city of Vienna. Lovers of urbanism will certainly find things of interest in the previously published images, but it is the floodplain patterns, which are now mainly similar to those of the Danube at Gemenc, Hungary, that are worth observing. It is a little known fact in Hungary that the Danube has caused far more serious problems in Vienna than in Budapest throughout the city's history. In historical times, the Danube flowed through a floodplain up to seven kilometres wide in Vienna, creating and destroying countless islands along this river section. The Viennese had an ambivalent relationship with the river, fearing its difficult crossing between the two banks and the many flood damages, but it was an advantage for the city in terms of trade. Around 1565, the main branch of the Danube moved away from the city and efforts by locals to bring the main shipping route back close to the city failed, leading to a compromise solution of extending the Vienna branch of the Danube, which later became the Donaukanal. 

Ugyanakkor a folyókanyarulatok vándorlása mellett a rendkívül fonatos meder gyakran okozott jégtorlaszokat. A budapestinél sokkal kevésbé stabilabb mederben a zátonyokon és szigetcsúcsokon kialakuló jégdugók gyakran eredményezték azt, hogy a télen levonult jeges árvíz kártételeinek felszámolása után a bécsiek már teljesen máshol találták meg a folyót. Ez az állandóan változó ártéri világ egyre inkább akadályává vált a város terjeszkedésének, amelyre megoldást kellett találni. Végül egy meglehetősen drasztikus beavatkozás szüntette meg a bécsi szigetvilágot 1870-1875 között, amikor is egy új, nyílegyenes medret ástak a Dunának, meghagyva egy széles, hasonlóan egyenes elöntési területet az árvizek számára. Az utóbbi időszak módosításai ezt a területet érintették, amikor a széles, kopár parti sáv helyén létrehozták a Donauinsel-t, melyet a bécsiek már sokkal inkább birtokba vehettek. 1875 után a lefűzött, kiszáradó folyókanyarulatok két utat jártak be. Ahol városi zöldfelületek területére estek, ott javarészt fennmaradtak (Prater, Alte Donau, Lobau, stb.), ahol viszont a város szövete ugrásra készen várta a kiszáradást, ott esetleg csak az utcák nyomvonala emlékeztet a régi medrekre (pl. Schwarze Lacke), többségük több méter feltöltés és beton alatt húzódnak. 

However, in addition to the migration of river meanders, the extremely braided riverbed was often clogged by iceblocks. In a much less stable bed than Budapest's, ice jams on sandbanks and islands often meant that, after the damage caused by the winter ice flood had been cleared up, the Viennese found the river in a completely different place. This ever-changing floodplain world became an increasing obstacle to the expansion of the city, and a solution had to be found. Eventually, a rather drastic intervention eliminated the Danubian archipelago in Vienna between 1870 and 1875, when a new, straight-edged bed was dredged for the Danube, leaving a wide, equally straight floodplain for the floods. More recent modifications to this wide, barren flood area included the creation of the Donauinsel, that was more easily occupied by the Viennese people. After 1875, the story of the newly created oxbows and drying river meanders took two paths. Where they fell into urban green spaces, they were largely preserved (Prater, Alte Donau, Lobau, etc.), but where the urban developers eager for more territory, only the street network may be reminiscent of the old riverbeds (e.g. Schwarze Lacke), most of them beneath several metres of landfill and concrete. 

Half a thousand years of river bend changes in Vienna 1529-2010 (source)

The nine detailed landscape reconstructions created using geographic information methods were almost begging for a .gif version. This version was most certainly created by the authors, but unfortunately the format is not compatible with the capabilities of the Guttenberg Galaxy. So I quickly put together my own version. In varying time-intervals, nine dates in total (1529, 1570, 1662-1683, 1704, 1780, 1825, 1875, 1912 and 2010), we can see the immediate surroundings of Vienna, with the Praterstern roughly in the centre. 

The Ancient Peninsula of Regensburg

MAGYARUL

It is a generally accepted view among local historians in Regensburg that the city's islands were formed from an extremely long and extremely narrow peninsula by the catastrophic flood of 1304. This serpentine stretch of land stretched from the mouth of the Naab to Regensburg, i.e. the estuary of the Naab ran parallel to the Danube for about six kilometres. There are, however, some aspects that may call into question the existence of this rare hydrological phenomenon.

I first came across the above illustration on the inside cover of the publication "Regensburg zur Römerzeit", which depicted the hydrological situation shown in the above picture as a fact. According to a brief description of the landscape, the Naab did not flow into the Danube at Mariaort in Roman times, but ran parallel to the Danube for almost six kilometres, passing Kneiting, Winzer, Steinweg and Stadamhof, taking the Regen river on the left bank and flowing into the Danube somewhere at the lower tip of the present-day Unterer Wöhrd, east of Regensburg. In other words, when the second stone bridge was built on the Danube between 1135 and 1146, the famous Steinerne Brücke was still arching over this peninsula to the north bank. The huge peninsula was carved up into four separate islands (Mariaorter Wöhrd, Winzer Wöhrd, and in Regensburg the Lower and Upper Wöhrd) by the catastrophic flood of 23 May 1304. Local vernacular is calling the Danubian islands Wöhrd, which derives from the Middle German word 'werd', while in northern Germany the more familiar sounding form 'Werder' is used.

The "Regensburg Peninsula" already appear in the work of Otto von Freising, who said that the Naab flowed into the Danube at Regensburg. The local chronicler Eberhard von Regensburg is consistent in his description of the events of 1304:

„Anno Domini 1304. Cum aqua Danubii transiens per pontem Ratisponensem omnio versus litus apuilonare declinasset, et litora prope civitatem sicca et arida reliquisset, ceves Ratisponenses artificiose et mulits laboribus et expensis ipsam aquam, ut iterum prope civitatem flueret, ad loca pristina per strues lignorum et congeries lapidum reduxerunt.”

Early medieval hydrographic conditions were already described by the local historians of Regensburg, Plato-Wild (1710-1777), Gemeiner (1726-1823) and Gumpelzhaimer (1766-1841), whose views were later confirmed by detailed research by Adolf Schmetzer. Karl Bauer, in his monumantal local history book (Regensburg - Kunst, Kultur und Alltagsgeschichte), adds to the above theory that at the time of the construction of the Roman legionary camp Castra Regina (A.D. 180), a change in the riverbed probably caused the Unterer Wöhrd to form a separate island. At Bauer, the date of the flood disaster was two days later, 25 May 1304. On that date, the Danube between Winzer and Pfaffenstein broke through the Regensburg Peninsula and the main riverbed was moved into the old bed of the Naab between the present-day Oberer Wöhrd and Stadtamhof. According to some local oral traditions, the northern branch of the Danube was still called the Naab around 1915.

The section of the Danube between the Naab and the Regen in 1829 (source)

The result was that the free imperial city of Regensburg lost its Danube port, its customs revenue, its mills ran dry, all of which threatened the city's economical power. As the city was in frequent dispute with the town of Stadt am Hof, on the other side of the old Naab, under the jurisdiction of the Bavarian prince-elector, the locals had to act very quickly. It is not clear whether in the same year or in the summer of 1305, during a very dry period when it was possible to cross the shallow Danube, a water control structure called Wöhrloch was built at the top of the Oberer Wöhrd, which was intended to both return most of the Danube's discharge to its original course and leave some (border) water between the Regensburg-owned Oberer Wöhrd and the neighbouring Stadamhof. The Wöhrloch, consisting of a combination lock and weir, was, like the stone bridge, a marvel of engineering on such a grand and rapid scale. However, for centuries it was the source of strife between the city of Regensburg and the Bavarian prince-elector, who wanted to widen the basin to allow larger ships to enter Stadtamhof, boosting trade. Disputes over water management sometimes led to the Wöhrloch being destroyed by the military.

The Wöhrloch in 1638 (source)

In addition to the historical plot, which is worthy of Ken Follett's 'Pillars of the Earth', the question arises: can such an unstable formation be created hydrologically on a river with such a variable flow over such a long period of time? Although the historical sources are clearly "pro-peninsula", there are some hydrological factors that may call into question its existence and its persistence over many centuries.

• The Danube reaches its most northerly point at Regensburg, where it makes an almost right-angled bend at Winzer, changing from a northeasterly to a southeasterly course. There is also a bend with similar parameters just above the mouth of the Naab, both of which have in common that they head towards a steep hillside. The development of the bend in the river has therefore washed the left bank year after year, and has thinned the peninsula most in the vicinity of Winzer, which is consistent with what historians say about the site of the 1304 breach. 
• The parameters of the peninsula also suggest that it was not very stable: it was 6 km long from the mouth of the Naab to Regensburg and probably 100 m wide at most. If we take the distance between the Roman castellum of Großprüfening and the hillside above Mariaort, the peninsula was located in a river floodplain cross-section of up to 600 metres in width. In such a section, major floods have had the opportunity to breach the floodplain several times over a period of 1200 years.
• The only permanent watercourse between the Naab and the Regen is on the left bank, the Brückelgraben. This is a relatively short stream with a low discharge, but it probably built up a cone of sediment in the Danube (or earlier in the Naab bed) from the alluvium carried by the hillside area during major rainfalls, forcing the river of the northern branch southwards, which may ultimately have caused the gradual thinning of the land mass. 

Based on the sources, it seems more likely that the Danube's longest peninsula did exist, but reconstructing exactly how long and how its gradual thinning took place would deserve further research.

Sources and literature:

• Christian Heinrich Kleinstäuber: Geschichte und Beschreibung der altberühmten Steinernen Brücke zu Regensburg. 1878.
• Iris Nießen, Doris Wollenberg: Aus Fluss wird Stadt – Die Stadtentwicklung im Osten von Regensburg im Fokus von Hochwassern und Landgewinnung. 2019.
• Oliver Wetter: Urban stream works in Central Europe 1200–1700: municipal administration, hydraulic engineering and flood reconstruction. 2019.
• Karl Bauer: Regensburg - Kunst, Kultur und Alltagsgeschichte. Buchverlag 2014. 6. kiadás
• Karlheinz Dietz, Thomas Fischer: Regensburg zur Römerzeit. Friedrich Pustet Verlag 2018.

L'ouverture du Rollerdamm

MAGYARUL

IN ENGLISH

Le 30 mai 1875, en présence de Sa Majesté François-Joseph Ier, empereur d'Autriche et roi de Hongrie, le Danube fut inauguré à Vienne lors d'une cérémonie dans son nouveau lit rectiligne et canalisé. Le 15 avril, un mois et demi avant la cérémonie d'inauguration, la digue de protection en terre (Rollerdamm) fut ouverte et le Danube entra dans son nouveau lit canalisé juste au-dessous du pont des chemins de fer du Nord-Ouest (Nordwestbahnbrücke). Trois jours plus tard, le premier bateau à vapeur franchissait déjà le nouveau tronçon. L'histoire de la Rollerdamm est reconstituée ci-dessous sur la base des écrits du livre Wasser | Stadt | Wien.

La digue de protection en terre (Rollerdamm) à Vienne le 10 avril. 1875. (Image originale)

À Vienne, le Danube était déjà un fleuve relativement régulé avant le début des grands travaux de régulation en 1870, malgré les méandres naturels qui subsistaient. La quasi-totalité des berges du lit principal avait été stabilisée en 1869 sur la base d'une planification locale ou centrale. Cependant, le lit principal, stabilisé par des épis, des blocs de pierre et des pieux, était encore trop large, créant un potentiel pour la formation de nouveaux bancs de graviers, comme dans le Gänsehaufen près du port de Kaisermühlen. À cette époque, les travaux de régularisation étaient encore principalement destinés à la navigation, la protection contre les inondations n'étant qu'une préoccupation secondaire. Lorsqu'en 1862, une embâcle inonda les faubourgs de Vienne, le gouvernement monarchique créa une commission de régulation du Danube, qui ne put commencer ses travaux qu'après la guerre perdue avec la Prusse en 1867. Les membres de la commission (ingénieurs, administrateurs et experts en navigation, chemins de fer) se partagèrent rapidement autour de deux positions très divergentes. Le groupe de Pasetti était en faveur d'un redressement du lit principal existant, tandis que l'autre groupe plaidait pour un nouveau lit unique et canalisé. La question est restée longtemps dans l'impasse et a finalement été tranchée par le retrait de Pasetti au profit des partisans de la version canalisée. Ce plan était principalement soutenu par les défenseurs du commerce et des transports.

L'entreprise française "Castor, Couvreux et Hersent", qui avait déjà fait ses preuves sur le canal de Suez, s'est vu attribuer le contrat. Le tracé du nouveau canal en courbe, établi en 1868, comportait trois points fixes : l'affleurement près de Nußdorf, le pilier récemment érigé de l'Ostbahnbrücke près de Stadlau et la section de la digue déjà achevée au niveau de la Lobau. Ce plan nécessitait deux grandes coupes sous et au-dessus de l'Ostbahnbrücke. L'entaille supérieure avait une longueur de 6 640 m, l'entaille inférieure une longueur de 2 550 m, et une zone d'inondation stérile de 475 m de large (Inundationsgebiet) devait être créée sur la rive gauche pour évacuer l'excédent d'eau des crues.

La position du Rollerdamm (source)

La section inférieure du nouveau Danube près de Freudenau à Weidenhaufen a été réalisée par la construction d'un fossé de 114 à 170 mètres de large, qui a ensuite été élargi par le Danube, emportant la plupart des sédiments vers le Marchfeld. La partie supérieure avait été entièrement excavée, mais lorsque le nouveau lit de la rivière fut dragué près de Nußdorf, les ouvriers eurent une mauvaise surprise : le lit de la rivière était jonché des restes de travaux d'ingénierie fluviale des siècles précédents. Pendant des années, les dragues à vapeur se sont efforcées de les dégager, mais les machines utilisées à l'époque étaient trop faibles pour enlever ces défenses massives. Au total, des milliers de pieux en bois datant de plusieurs siècles et 18 kilomètres et demi de structures en bois diverses furent retirés.

Pour la construction du canal, les dragues à vapeur et les transporteurs ont été utilisés pour la première fois à grande échelle et ont dû déplacer une quantité incroyable de sédiments pour l'époque. La plupart des 16,4 millions de mètres cubes de sédiments, de gravier et de sable excavés ont été utilisés pour remplir les zones suburbaines de Brigittenau et de Leopoldstadt, contribuant ainsi grandement à l'augmentation de la zone urbaine de Vienne. Le nouveau lit du Danube à Vienne comprenait la construction de digues de protection contre les inondations des deux côtés, l'approfondissement du canal du Danube et la construction de cinq nouveaux ponts sur le Danube.

Lors du dragage du nouveau lit, une étroite digue de terre appelée "Rollerdamm" a été laissée dans la partie la plus septentrionale du lit, maintenant jusqu'au dernier moment la direction de l'écoulement vers l'Alte Donau. À l'origine, cette digue n'était pas perpendiculaire au nouveau lit de la rivière, mais suivait la ligne d'écoulement de l'Alte Donau depuis la rive gauche des ponts actuels de Florisdorf jusqu'au Handelskai sur la droite. Il était également surmonté d'un chemin de fer industriel, dont l'un des terminaux se trouvait sur l'actuelle Friedrich-Engels-Platz. Le 15 avril 1875, un mois et demi avant la cérémonie d'ouverture officielle, le Rollerdamm a été ouvert sous la direction du géologue Eduard Suess, la petite brèche étant rapidement élargie par le Danube jusqu'à ce que le barrage soit complètement emporté sur la largeur du nouveau lit du fleuve.

Dans un premier temps, le Danube s'est montré réticent à occuper le nouveau lit. Après le retrait des crues de printemps, la fermeture technique de l'Alte Donau a commencé, mais dans le lit rétréci, le fleuve exerçait encore une force considérable, déplaçant les bateaux chargés de pierres enfoncés dans le lit, détruisant la digue en cours de construction et creusant de profondes fosses dans les sédiments meubles. Finalement, des structures en bois remplies de blocs rocheux ont été reliées entre elles par des câbles et mises en place sur des voies ferrées, fermant définitivement l'ancien lit de la rivière. Peu de temps après, en février 1876, le premier "test de résistance" du nouveau système d'approvisionnement en eau de Vienne a été effectué. Dans le tronçon du Danube encore non régulé de Vienne, sous le pont Ostbahnbrücke à Stadlau, la glace s'entassa et l'eau en crue, repoussée par le barrage de glace, trouva son exutoire dans le bras mort de l'Alte Donau. La digue inférieure et la digue supérieure se rompirent et les trente-trois bateaux de la compagnie "Castor, Couvreux et Hersent" furent emportés hors de l'ancien bras et mis à terre, endommagés, dans une prairie fluviale près de Fischamend. Le 25 février 1876, le London Times a également fit état de la prétendue défaillance totale des ouvrages de régulation à Vienne et publia une fausse nouvelle selon laquelle le nouveau cimetière central de Vienne était tellement inondé que les cadavres avaient été emportés hors de leurs tombes.

L'ouverture du Rollerdamm le 15 avril 1875.
Au-delà se trouve le pont du chemin de fer du Nord-Ouest, construit en 1872. (source)

Après la fermeture du Vieux Danube (Alte Donau), de vastes étendues de champs de graviers furent laissées à sec. La zone a rapidement été envahie par les baigneurs viennois. En leur faveur, les autorités ont dragué le bras mort pour améliorer la qualité de l'eau, ce qui a finalement permis à cette zone humide urbaine de survivre. En raison de la régulation du Danube à Vienne, le niveau de la nappe phréatique s'est abaissé de 1,3 mètre en moyenne, de sorte que la valeur immobilière de la plaine inondable du Danube a fortement augmenté parallèlement à celle des décharges. La disparition des méandres naturels, la formation d'îles et de bancs de graviers et l'arrêt de leur migration ont finalement conduit à l'urbanisation rapide des berges et, parallèlement, à la dégradation et à la disparition rapides des habitats naturels.

Traduit par deepl.com et Eric Baude (http://www.danube-culture.org/).