Around the island

When I walked from Vienna towards Bratislava along the Danube, I noticed - you can't help but notice - an island in the middle of the river. Donauinsel is 21km long and 70-210m wide. It runs the length of Vienna - and it's completely artificial. Here's a map showing 'the island':

So why is the island there? Simple answer. Flood protection. Let's look at what the bank of the Danube looked like before Donauinsel was created:

TARS631 (Attribution or Attribution), via Wikimedia Commons

There have been a number of floods in Vienna. This shows 1954:

After the 1954 flood, authorities in Austria wanted to make sure it never happened again. The volume of water passing through the Danube was 9 600 m³/s. The specification - over-specification to the opposition - was the great flood of 1501, which was about 50% worse at 14 000 m³/s. In 1501, to put this into perspective, water reached Old Town Square in Prague, which is quite a way above the river. 

So why does building an island work? Maybe think of it as a bathtub. A wide bath can hold much more water than a narrow bath. In the same way, two rivers can hold much more water than one. Most of the time, the one on the right of the map (the New River, taking most of the area of the flood plain on the Wikipedia image) is closed off by weirs and a pleasant place for swimming. When it rains heavily, the weirs are opened and the water can run down either channel. 

Vienna dug up the flood plain and built an island for flood protection. Little did they know that they were building what would be one of the most-visited recreational sites in the city. 

I was determined to walk the length and breadth of the island. It's about 42km. As usual, I did no research before going. I knew where I was starting and where I could break part way, but otherwise the journey was totally unplanned. I hope you enjoy it as much as I did.

Coming out of the U-Bahn station, that's the view looking towards the east (left) bank of the island. It was totally unplanned, but the skyscrapers (Donau City) would provide a reference point for the inevitable 'are we there yet?' question I would ask myself on the finishing leg.

And here's the river. The lack of flow tells you that it's the New River. I decided to go clockwise round the island (if you can go clockwise round something shaped like a worm), heading south along the New River for a start.

The central parts of the island are quite formal and planted. Here we have planted lime (or linden) trees. Which leads me to a story about my grandmother. CRITIC: another one?

Well, I've almost run out. My grandparents lived at number 92, which had a nameplate saying 'LINDEN LEA'. You were posh if your house had a name as well as a number. Early- and mid-twentieth century planners attempting to bring countryside sophistication to the towns.

However, the island soon moves to being quite wild as you move towards the ends. But here we have a hollyhock - a garden biennial I'm not used to seeing in the wild - becoming established by the New River, growing amongst the grasses.

Even though the river is twice as wide, there's still a need for flood protection.

We see the pink crown vetch here. It may have been planted or encouraged, as it would stabilise the bank.

Looking back to Donau City.

Weir 1, half way along the island. Why would you have a weir half-way along the island? Well, the Danube falls 8-9 metres along the length of Vienna. Think of the New Danube as being a canal during normal weather. Its level has to be close to constant, or all the water flows towards the lower end, and there is no water at the higher end. What do we do on canals to maintain the level of the water? We build locks. Think of Weir 1 as a big lock gate without a lock. 




But ... how do I manage to take my ship beyond the weir? Those are typical New Danube ships. You carry it.

Barbados/Donau. One of many beach bars on the New River, emphasising its role as a tourist attraction.

The main line to Budapest is carried over the river by the Stadlauer Ostbahnbrücke in the distance. In the foreground we see reeds. They may be natural or planted, but they would certainly be encouraged, as they tie the bank together, and will recover from a ducking.

This part of the island is wetter, so no crown vetch. But we do have eastern daisy fleabane, which grows here where the common daisy from your lawn would not. You also see red clover and tufted vetch.

The two taller trees are black poplars. They are closely related to Lombardy Poplars which you see in lines on the edges of golf courses. They're roughly the age of the island, so they may be planted. However, they are suited to the conditions, so they are likely to remain.

A Vienna magpie. CRITIC: Ian, that's a hooded crow.

I know it's a hooded crow. It's just that I've never seen a magpie in Vienna, and I've often seen hooded crows. Don't ask why. No-one can explain it.

Swans on the New River. I'd just heard one take off. 

Here's a swan taking off. It's like a radio with valves warming up. The time in Britain is twelve noon, in Germany it's one o'clock, but home and away it's time for Two-Way Family Favourites.

A coxed four. The New Danube is ideal for rowing, being flat, largely straight and lacking current. The blue plant we see in the foreground is Echium vulgare, otherwise known as viper's bugloss. More on this later.

Comfrey by the edge of the river.

We end up with recreation management on the flood management area. Rowers - priority to your left, swimmers; priority to your right, rowers.

The Waluliso Bridge - a pontoon bridge with room for your New Danube ship to pass through closest to the island. This bridge, and the upstream Copa Bridge, are rotated to match the flow of the river during the winter. There is no way that a pontoon bridge could cope with 5200 m³/s passing over it without being torn away.

One of the many things about the island is that there is something for everyone. Here, it's no dogs during the season, but on other parts of the island dogs can run free.

A cygnet lying close to a sign saying to leave cygnets (and other wild animals) alone. 

Approaching the southernmost point on the island.

The end of the island. An announcement to ships that they are entering Vienna Lobau Port.

And here's our first main Danube ship as the Danube becomes one river.

The habitat changes completely as we move to the west (right) bank. This is Dyer's chamomile. It likes the sun-baked soil on the main Danube side.

The path is very different here, and we see a hare. This feels like 1870s riverbank to me, and the hares may have been here all along rather than finding their way in via a bridge.

I love these small islands in the main Danube. There are many of them. They are likely to be natural, and created as a result of the big island being built on the flood plain.

I'm really not good at photographing butterflies. Here's a comma. There was one butterfly which I saw hundreds of on the other side of the island, but they wouldn't keep still for long enough for me to photograph them.

A tree stump, no doubt uprooted somewhere upstream, has found its resting place on a sandbank. It may be a relic of the 2024 flood. When the Danube is in full flood and both channels are open, the New River will almost certainly have equivalent debris, which will need to be cleared in the spring to maintain the swimming and rowing paradise we saw earlier.

An invasive weed, the tree of heaven (Ailanthus altissima). Nearly all of the trees we've seen so far have been native, but this one certainly isn't. 

Soapwort. Often found on riverbanks.

Push tug and barge in the background, more echium in the foreground. A strong contrast between the working river and leisure on the island.



Dry, nutrient poor soil, and all that grows is the Carthusian pink.

So this is the main cycle path, isn't it?

Erm no. But what's that fast flowing water doing here?




Back to the path the sensible people use, here are some bracket fungi on a tree.

In contrast with the planted lime trees we saw earlier, here's a mature wild specimen. 

Crossing the inland waterway I saw earlier. Still quite fast moving.

That's a dam - the Freudenau dam. It's a hydroelectric plant. It could power a city the size of Coventry, Leicester, Brno or Bratislava. The water we saw in the previous pictures is the fish bypass channel.

What's interesting is that Freudenau was Vienna's choice, unlike the building of Donauinsel which was controversial at the time. A 1991 referendum was held in Vienna, and a large majority were in favour.

The Danube isn't wider above the dam, as you might expect from pictures of the Hoover Dam and the Aswan Dam. That's because the water isn't stored. It's simply a way of extracting energy from the water as it passes through.

And how big are the turbines? In the same way we measure the size of railway stations by comparison to Wembley Stadium, we measure turbines in terms of double-decker buses. There are six turbines, and they are each wider than a double decker bus is long. Who needs proper mathematics when we have double-decker buses?

Here's a picture from a drone or a helicopter which gives a fantastic view which I couldn't possible achieve from riverside.

And how many of you were whistling this to yourselves after seeing the picture above?

Along with the lady's bedstraw, we see an everlasting pea. It looks like a sweet pea, but unfortunately it doesn't have its scent. Is it natural or planted? It could be either. Given it's on the west side of the island, it could have been there since the 1870s. 



A rambling rose. This one definitely looks to be planted.

Fewer of you would have whistled this one.

Here's the entry to the fish bypass channel.

So what on earth is this? It's the pool pass, which regulates the water in the fish bypass channel. Engineering on a somewhat smaller scale than the main dam, but essential nonetheless.

Here, largely hidden from view on the island, and totally hidden from the east bank of the New Danube, is the Port of Vienna. It handles 12 million tonnes of cargo annually - that's about 865 lorry loads which travel by river rather than by road. Alternatively, it's 22 full freight trains per day. It's big.

Here's a Robinia. It's a North American import, arriving into Europe via ports like the one in the last photograph.

I know that one. It's a willow. CRITIC: Even I know it's an oleaster.

OK, it's an oleaster. At least I know to pronounce it not ending in Easter. It's quite invasive, but it has the advantage of producing edible olive-like fruit. Also it stabilises the bank.

 
A reminder of why we need to stabilise the bank. The island is a big sandpit, really.

Chicory. Do any of you remember Camp Coffee? That includes chicory in its ingredients.

That's the Stadlauer Ostbahnbrücke heading back the other way. It's undergoing anti-corrosion maintenance.

Donau City in the distance. So we are close to where we started, but on the other bank.

This is a modern riverside block of flats (€350,000-€550,000 for a 2-3 room flat with a river view and a balcony). The tower behind is the Donauturm transmission mast. At 252m it's Vienna tallest structure. 

Slow down on your bike. There are a lot of families in the central area of the island.

The Franz-von-Assisi-Kirche.

Very pretty for tourists, but the cobbles are difficult for tired feet.

The Floridsdorfer Brücke in the foreground was the end of the first day's walking. In the distance is the Millenium Tower. About 40 000 steps, then back to my favourite Thai restaurant. They know my order - chicken red curry with wheat beer.

Start of day 2. We're continuing clockwise round Donauinsel, so we're still on the west bank from the map at the start of the article. It's a scorcher. Looking back from the island towards Handelskai (where I got off the train), this is the Austria Center Vienna. Vienna is one of four United Nations headquarters cities, and the building hosts the  International Atomic Energy Agency, among others.

Bird's foot trefoil, or eggs and bacon. A semi-wild plant in a cultivated area of the island - it's easy to walk from the U-Bahn, so there are more people here than towards the ends of the island.

Viburnum opulus, or guelder rose. A planted species which I saw (but not in flower) on the other side of the island as well.

A school? On an uninhabited island. But why?

Well, it's definitely a school. But can you see from the second photograph that it's actually a boat? The name of the road - Schulschiff, school ship - should have given me a clue. School on a boat - how cool is that? 

One of the specialities of the school is trips to study the nature of the island. Those of you who grew up near me may remember bus trips to Spurn Point (at the mouth of the Humber) and Gibraltar Point (to the south of Skegness). Just imagine being able to do the same sort of trip by walking out of your classroom on a boat rather than spending hours on a bus. 

Dogs - and a few brave people - paddle. Meanwhile, the swans swim on oblivious.

Soapwort again, but a far larger clump.

Spotted knapweed. Meanwhile, on the other side of the river, we see a crane, and building continues in Donaustadt. 

Echium galore.

CRITIC: Are you sure it's not bluebells?

It's not flax either, but I can see why you might think it would be bluebells from the number. But - erm - not from the date.

CRITIC: you didn't take that photo, Ian. It's a postcard.

But sometimes I'm just lucky. The church of St Leopold on Leopoldsberg, with a tourist boat passing by.

A nudist. Nudism is allowed along a small section of the island, west and east. It is Vienna, after all.

Yachts of the Main Danube. A bit of a contrast from the ships of the New Danube.

A pair of mallard contemplating, above ground and by the water on a hot day.

Echium again.

CRITIC: that's not the same plant that I thought was bluebells.

I know it isn't. But it's not Echium vulgare. It's Echium plantagineum. That's a first for me, and, apparently, it's rare for them to grow close together.

It's wetter here. That's meadowsweet amongst the grasses.

St John's Wort. A herb with lots of uses, including for mild depression.

Lady's bedstraw in abundance.

As I said earlier, I love the natural islands. With the fallen log, this looks all so natural.

Crown vetch again. 

There are lots of sandy beaches on the Main Danube. Usually, you find individuals, couples or small groups there.

We're close to Nordende. The river's a lot broader here. We've long left Vienna urban area - the village you see across the river is Klosterneuburg.

Hawksweed ox-tongue in the foreground, smooth hawksbeard in the background.

The north end. The stones are from around 1870, and the only remnant I've found of that early attempt to manage the Danube.

A bridge for cyclists on to the northern end of the island - above the weir which closes off water to the New Danube during good weather.

Looking up river from a higher vantage point than the stones.

Water with rather unpleasant looking algae in it. This part is in Lower Austria rather than Vienna, but there's no evidence of a different algae management policy between the two areas.

Echium. Possibly the best photo of it in the two days.

Amongst the echium, we see great mullein.

Robinia suckers. That's going to take over very quickly, unless it's managed.

CRITIC: Ian, why are you showing us three dead trees?

Look carefully. Only one of them is dead. The other two are regenerating from further down the tree, as willows do. In urban areas, you would need to take out the dead wood for fear of accidents to children, but we're far enough out in the wild to let nature do the reclamation.

New Danube ships.

I can see the journey's end. Hopefully it's not a mirage in the heat.

Boris bikes. Have you already seen Vienna from a bike?

On the New Danube, we see large groups of people, in contrast to the small groups, couples and individuals on the Main Danube.

Journey's end. Donau City.

CRITIC: so what was ubiquitous, Ian?

Well, on the second day, sunbathers. But that was because it was hot. Over the two days, echium. Echium everywhere. 

CRITIC: And what are your main points to convey at the end?

Three things. Firstly, I just don't see how it was possible that the authorities didn't realise that they were building a tourist attraction. Yes, that wasn't the point of the island, but it seems fairly obvious that it would be a magnet to tourists.

Secondly, note that a lot of the plants which are common on the old side are present on the new side. We saw that in lots of the photos. The old side has had 100 plus more years to develop, so just imagine what the island will be like as a whole in a century.

Thirdly, Prague flooded badly in 2002. Vienna didn't. In 1501 - the flood that set the design specification for Donauinsel - water reached Old Town Square in Prague. In 2002, a worse flood, it nearly did again; only temporary barriers erected two years earlier kept it out, while basements flooded anyway through the rising water table. Vienna was untouched. The Viennese made a controversial decision in 1969, stuck with it through nearly two decades of construction, and in 2002 it worked exactly as intended. Sometimes the engineers are right.