One of Europe’s largest artificial river waves for river surfers of all proficiency levels has been put in operation in early May in Ebensee in the Upper Austrian Salzkammergut region.

Four and a half years of planning and elaborate negotiations with the local authorities went into the implementation of this spectacular project, which was spearheaded by a team of river surfing enthusiasts led by the project’s initiator, Max Neuböck. The facility’s core element is the so-called “wave shaper”, a 16-ton gate construction made from solid steel, which was manufactured and installed by Upper Austrian hydraulic steelwork engineering specialist Braun Maschinenfabrik. Well-known for their “classic” hydro steel constructions, the seasoned hydro steelwork engineers from Vöcklabruck were able to leverage their vast experience and know-how in this ambitious project.

It was in 2007 when young Upper Austrian Max Neuböck was captivated by the thrill of riding a standing river wave. He has never lost that initial fascination. “I used to surf the natural waves on the river Traun at an early age. That was a formative experience for me. It sparked my vision of setting up an artificial wave to let enthusiasts of any age share in that terrific river surfing experience,” says Neuböck. Together with a small team he went ahead and took “Project The RiverWave” off the ground and into the initial planning stage around five years ago. Right from the start they were faced with the double challenge of having to solve the implied technical and  ecological issues while carrying the project  through a stringent planning permission procedure. “We’d been in contact with the authorities early into the process, so we knew straight away what was required to do the project,” says Neuböck. “In the end, that helped us get through the official proceedings without any problems.”

GETTING A US EXPERT ON BOARD
The first and most pressing need was to find the optimum installation site. Key criteria included a sufficient drop over a short distance, as well as the required flow rate. “The spot we found meets all these conditions to a tee. It’s got a 1.30 m drop over a 50 m stretch with a sufficient water flow, as it’s located just a little downstream of the Traun and Ischl confluence. Incidentally, the site is just about 400 m from where I used to surf the Traun. It’s like things have come full circle, starting with my initial fascination with the sport, to the vision that grew out of it and leading to its final implementation here,” says the project’s initiator. Talking of which, he mentions how, early into the project, he was able to win a specialist in artificial river waves to join the team: Ben Nison, who works with US-based industry specialist McLaughlin Whitewater Design Group (MWDG) from Colorado. Says Neuböck, “With the assistance of Ben Nison from MWDG we were able to start model testing already in the late autumn of 2017. Overall we took some 1,000 water level measurements and ran numerous tests, which took us around 700 working hours – all to make sure we’d be getting the best possible wave.” That done, the preparations for the new surfing wave were complete.

WANTED: HYDRO STEEL ENGINEERS
With all official permits granted, the official kick-off to the construction went ahead on August 7 last year. Immediately after that the dredgers went busy at the construction site on the Traun. Late November last year marked the achievement of the first project milestone: the base plate, which incorporates around 250 cubic metres of concrete and 13 tons of steel, was finally complete. The artificial channel was slowly taking shape. Just before the end of the year the entire concrete work for the wave channel was finished. The base structure was now ready. The only thing missing at that point was the project’s core element – the so-called “wave shaper”, which would be installed a few weeks later. For obvious reasons, the operator kept all their care and attention focussed on the very component that actually generates the standing wave. “We searched the Upper Austrian hydro steel engineering market – until we finally found the perfect partner for our project: Braun Maschinenfabrik of Vöcklabruck. We realised pretty quickly that Braun not only has vast experience in hydropower construction. They were also open to projects like ours, as they had done quite a few special installations before,” explains Neuböck, adding that Braun’s engineers came up with some crucial improvements themselves.

WAVESHAPER IS MAKING WAVES
The WaveShaper is basically a valve construction consisting of two laterally coupled, movable steel valves with a combined weight of 16 metric tons. “The upstream, smaller one of the two valves is basically a weir baffle of the kind used in hydropower facilities. It regulates the water flow into the channel,” as Max Neuböck explains. “The downstream valve is freely hinged to the upper one and varies the water discharge angle. The ramp has a small attachment to divert the water flow upwards.” Thanks to this arrangement, the valve unit creates what is known as a “hydraulic jump”, which is needed to form the standing river wave. This physical phenomenon, says THE WAVE’s initiator, is achieved by sending water at high speed over a ramp and into a body of stagnant water. If the water stream flows downward, the water forms a sort of roll. But if it is directed upwards, as in this case, it creates a standing wave. The important thing for the river surfers is that the wave never breaks. This is necessary to enable them to ride the wave as their ability allows, with the wave moving only sideways. It is crucial for the construction to be movable and able to adjust to the highly fluctuating water levels of the Traun river. “Here at the wave site we have water levels between 1 m and 2.80 m. The movable valves adjust to the current water level automatically, so that we get a constant, optimum wave, even at high-water mark,” says Max Neuböck with a smile.

MODEL TESTING IS ESSENTIAL
To allow the “WaveShaper” to be designed to the exact site-specific conditions, Neuböck and his team had to measure the water levels regularly for a whole year. In addition to a two-dimensional model, the engineers constructed a real-life model at a 1:8 scale to research important details for the design of the channel and the “WaveShaper”. “Based on the results and the measurement data we were able to go ahead with the design of the valve construction, together with our wave engineer from Colorado and Braun’s engineers. It took a lot of brains, brawn and know-how to get everything right. The resulting design is crucial for the wave generator to work as it should,” says the operator. But there was yet another aspect to take into account: the ultimate safety of the surfers, who had to be protected from the drive cylinders. These were flush-mounted into recesses in the concrete wall and covered with protective plates to prevent both injuries to the surfers and the collection of sediment in this area. “This was another issue where we were happy to have the team from Braun Maschinenfabrik to contribute their constructive ideas.” Braun’s project manager, Roman Unterberger, agrees, adding that “this project allowed us to bring our decades worth of expert knowledge to bear. That included the experience from past special projects, which we were able to apply and develop further. One of the biggest challenges for us was the lack of proper documentation on specific problems that we had to solve in this particular installation. In the end that helped to spur on our own creativity and imagination.”

IDEAL DESIGN THROUGH HIGH-TECH
It was already during the initial meeting between the river surfing visionary and the hydro steelwork engineers that they came up with a rough construction concept for the “Wave- Shaper” “As time went on, the geometric characteristics were taking shape, reflecting the customer’s constantly refined model test results. We worked out or own drafts, and together with Max Neuböck and his team we went step by step to find the optimum solution for the valve construction,” as Roman Unterberger remembers. This process also involved the use of numerical methods, such as the Finite Element Method (FEM) or Computational Fluid Dynamics (CFD). Special attention was paid to the joint-type link between the two valves. For this purpose the two components were joined already at Brown’s construction facilities, which allowed giving them a “dry run” to test the movements required for generating the wave. On February 18, the time had finally come. With the high-voltage supply switched off, the two valves were mounted into place without any major difficulties and in beautiful sunshine. For Max Neuböck and his team it was the completion of one of the project’s biggest milestones.

SOFTWARE FROM THE HYDRO STEELWORK PROS
It was not just the manufacture and installation of the large core components, such as the valves, bearing blocks, drive unit support, protective covers, safety rack and hydraulic units, that required the expertise of an experienced hydraulic steelwork engineering firm. That know-how was also crucial in designing the controls for the valve system. After all, the valves had to be self-adjustable to the water levels of the Traun river to maintain a constant wave quality. “Our specialists had to wire and assemble the switchgear. Besides that, the required software for controlling the “WaveShaper” is also a product of our in-house electrical engineering department,” explains Roman Unterberger.  
Everything is controlled either directly via switches in the switch control box or remotely over the Internet using a mobile device. This allows an operator to stand next to the facility and adjust the wave to the surfers’ needs. At high-water mark, the valve unit can be shifted at a simple push of a button to transform the surfing channel into a discharge outlet.

RIVER SURFING – A NEW TRENDY SPORT
Before the facility could be taken into operation in early May, the engineers had to put the finishing touches on the fish ladder –  a vertical-slot pass – which was installed next to the wave channel. Also, the workers had to put down the turf, erect the seating steps on the riverside and complete the toilet units. Overall, Max Neuböck and his co-initiators invested €1.5 million in their dream project. With the project complete, river surfing on the Traun is now set to become the next cool, trendy sport in the area.