Last year a sleek new walkway was added to Geneva’s iconic 140 metre high jet of water, known as the Jet d’eau, Bill Harby met the team and got a look at the machinery that makes it all happen.
Viewing Geneva’s famous landmark, the Jet d’eau, up close is now a breeze for all, including the disabled. A new wooden walkway out to it opened last June. The award-winning bridge pictured below was designed by Ingeni.
Before the new walkway was added, those hoping to get close to the nozzle, which shoots a mixture of water and air as high as 140 metres, had to walk on a narrow cement jetty built in 1891, with no wheelchair access.
The new wood plank walkway – 3.8 metres wide and 200 metres long – has no steps, so now even those in wheelchairs can get within a few metres of the nozzle, for dramatic views and a chance to get a shower if the wind changes!
It pumps out 500 litres of water per second. The video below shows drone footage of the jet in action.
A new LED (light emitting diode) system replaces the old lights, saving energy and allowing the fountain to be lit in a variety of colours at night.
The famous Swiss landmark first spouted its watery plume on this site in 1891, but its history goes back to 1886, when the rapidly expanding city opened a nearby hydraulic pumping station on the Rhone river to serve local artisans. Much of the water was used to power factory machines. At the end of each workday, when the machines were shut down, excess pressure built up in the system, so a valve was needed to release it. This valve created Geneva’s first aquatic plume, a 30-metre high fountain of water.
Some visionary saw the crowd-pleasing potential of such a jet and, in 1891, the city built a new fountain at its present site. It rose to a maximum height of 90 metres.
That fountain used city drinking water until 1951 when a completely new, more powerful pumping system began taking water directly from the lake. Combined with a new nozzle, the jet could now push water up to a maximum of 140 meters.
“The exact height depends on the wind,” says Gérard Luyet, who oversees the Jet d’eau for SIG (Services Industriels de Genève), the Canton of Geneva’s energy agency. “When there is a slight wind, the water at the top of the jet is pushed to the side, so it goes higher. If there is no wind, the water falls back down on the rising water, so the fountain cannot go so high.”
The fountain begins at its nozzle, which is just 10 cm. in diameter. It shoots 500 litres of water per second at a speed of 200 km per hour. At any given moment, 7,000 litres (7 metric tonnes) of water are in the air.
At the nozzle, the water is mixed with air to form countless bubbles, turning the fountain white, making it visible for many kilometres.
The fountain is propelled by dual motors and pumps housed in a water-tight compartment mostly below the waterline.
The fountain is operated each day by a team of five volunteers, each one a retired SIG employee. If the operator sees that the wind is too strong or the temperature is dropping too low, he can shut off the fountain instantly.
The budget for running the Jet d’eau is CHF 800,000 per year. The tours (in French or English), last 30 to 45 minutes, and are open to any group of 10 to 12 people. Mandatory booking can be made online.
The tour includes the pumping station. Visitors descend via a short ladder into a small circular room where the giant motors (named Salève and Jura, after the mountain ranges on either side of Geneva) and pumps do their work – switched off during the tour, which takes place only when the fountain is not operating. The room is spotless, and includes a display of the huge old wrenches that were once used to maintain earlier machines.
After the tour, when the jet once again shoots high into the sky, visitors can stand near its base and contemplate this feat of engineering and imagination as the mist drifts down around them.
2017 Jet d’eau Hours of Operation
2 Jan – 5 Mar 2017, 10:00 – 16:00
6 Mar – 30 Apr, 10:00 until sunset and then until 22:30 with lights
1 May – 10 Sep, 9:00 – 23:15
11 Sep – 29 Oct, 10:00 until sunset and then until 22:30 with lights
30 Oct – 15 Nov, closed for maintenance
16 Nov – 4 Mar 2018, 10:00 – 16:00
By Bill Harby
The video below summarises the jet’s history (in French) – Take a 5 minute French test now