Secret Rivers.

Challenge: 2 (training shoe)  
Route: Auhof holding pools via Wolf in der Au and Mariabrunn
Length: 9.5km (including detours)
Start point: Wien river entrance ramp on Lilienberggasse in 1130 Vienna, at the corner of Wientalstraße
Coordinates: 48°11'46.48"N, 16°15'37.91"E  
Public transport: U4 > Hütteldorf station (4 minutes by foot to the start point)    

ROUTE DESCRIPTION  
The river Wien, in the west of Vienna. Even for an Urb, it's a curious sight. I'm standing by a listed tower, the motorway is over from me, next to me is a wetland habitat surrounded by walls, and below me is an oil canister, overgrown by wild chamomile and peppermint. The whole route is a heart-warming example of how nature is able to overcome the concrete and win back its habitats.
 
A while ago, an official bicycle and walking track was created through the channel, making it very accessible. Little detours to the holding pools are also advisable, because rare plants and animals, such as beaver, muskrat, grey heron and storks can be seen here. It's a good idea to have wellies in your backpack, otherwise your journeys of pool exploration will be extremely limited, because even in high summer, large lakes of mud collect here. At the end of the route there is also an official barbecue area. There's sure to be room in the backpack for a metal grill, a bit of charcoal, matches and a couple of spuds.    

Go to Google-Maps


ROUTE  
The entrance ramp to the Auhof channel is at the intersection of Lilienberggasse and Wientalstraße. Go past the barrier and simply follow the route laid out along the river Wien out of town. If you want to climb down to the first holding pool, just stop at the underpass to Ferdinand-Wolf-Park, and cross the bridge there. Afterwards the route to the right under the motorway leads directly to the pool. Back at the channel, carry on along the river until it crosses Badgasse (approx. 2km). There cross the bridge and go left to the barbecue area. The way back is exactly the same, except that after the river superintendent’s, the parallel route heads upwards (travelling along near the railway) and comes to the third pool over ‘Wolf in der Au’ bridge, via steps. Back at the tunnel to Ferdinand-Wolf-Park, there is the option to take the underpass, and go back through the park by following the map.  
 
HISTORY
Normally the Wien looks like a tiny stream in an oversized channel, but still waters run deep, as the saying goes, and this river can become deep dangerously quickly. Usually the Wien flows at 200 litres per second, but this can rise to 450,000 within two hours. It is therefore necessary for the Wien to have such a large channel through the city, and also six holding pools – the Auhof holding pools – to cope with rapidly rising and falling water. To relieve pressure on this system, the Wientalkanal channel was built in 2003, to take a proportion of the water directly to the Danube. Now mother nature can do her own thing in the holding pools, and has created the largest wetland habitats in the west of Vienna.    

NEOBIOTA – THE ILLEGAL IMIGRANTS
The demolition and reintegration of the Auhof holding pools has allowed domestic plant and animal species to reclaim their habitats. However, not just them, but also neobiota – species introduced to the ecosystem by humans. The most dangerous plant to this area is Japanese knotweed, a garden plant. It is very invasive, and is a real danger to our existing reed beds. The biologists responsible for the area have nothing against simply ripping it out, and the local gardeners are also engaged in an ongoing battle with the species. But you have to get the whole plant, as any part of it can go to seed. So it's up to you Urbs – hunt down this enemy shrubbery or accept its immigration and observe?!    

AREA TIPPS
River Superintendent Access Restrictions;
Generally during high water, and from 1st November to 20th March    

Bergmillergasse Skatepark
Vienna's biggest skatepark, 700m²
For just about all ages
1140 Vienna, 8 Bergmillergasse  
UrbTV contribution here!   

Auhof Holding Pools Barbecue Area Water, WC, benches and tables
1140 Vienna, entrance near  Karl-Lueger-Brücke bridge  

BOOK TIP
Aliens. Neobiota in Österreich.  
Böhlau, Vienna 2005, ISBN 3-205-77346-2  

More information in the WIEN GEHT book on pages 60-64.