As people stand by and marvel at the spectacle of Bradford’s new water feature, few will be aware of the magic behind it.

But as they take a closer look, they might realise that all is not as it seems.

Inspect a small spurt of water, and it suddenly shoots 3ft into the air. Hover beside a taller fountain, and it suddenly shrinks.

You might be inclined to think that mysterious forces are at work – and you’d be right.

It may be hard to believe, but the fountains in City Park are watching you. State-of-the-art technology enables the jets of water to react to the movements of people.

Jonathan Laventhol, the park’s principal consultant with responsibility for the interactive artworks, calls them introverted and extroverted fountains.

“Some taller jets will retreat and become very small when people approach them, while smaller ones will shoot up in your face in a cartoon kind of moment.” he explains. “Others, when approached, will hide themselves away completely.”

Inside the Pavilion adjoining the park, Jonathan stands before a black box about the size of wheelie bin, which houses a control panel no bigger than a laptop computer.

The screen shows the park, upon which are dotted half a dozen small red circles. “This is real time, and those rings show the positions of people walking around,” he says. “Cameras on the tops of columns link to this panel and monitor movements.

“The overall purpose is to have interesting ‘scribbles’ that move around, so the fountains respond,” says Jonathan, “They are very playful.”

Laser projections – which Jonathan describes as ‘Dalek-like’ – also move around. “Some blobs of light are jelly-like and move around the park reacting to people and chasing them. Some are star-shaped, some angular, and some like snakes.”

The shapes come in a rainbow of colours – oranges, reds, purples and blues.

“The fountains also have lights underneath which we control as part of the orchestrated piece,” adds Jonathan, who, amazingly, can work the jets from his mobile phone, allowing him to conduct the water and light orchestra from anywhere in the world.

As well as being in tune with the movements of people, the fountains are programmed to respond to the weather. “On a calm day they will be more sedate, and when the wind picks up they will go a little crazy,” says Jonathan, who has worked on prestigious projects such as The Dome in London, but never a water feature.

“Much of the pleasure comes in that the park is not a fixed, static thing. We want to make it a point of interest for the people of Bradford and visitors. We want them to ask: ‘What are the fountains doing today?’”

He adds: “My friend came with his children and it took under 20 seconds for them to go in and get drenched.”

Things are just as exciting beneath the surface, in a spacious room beneath the Pavilion where pipes and cylinders puff and hiss like steam trains. This is the plant room, where a vast network of pipes and pressure gauges drive water to the surface from a huge underground pool.

After climbing a ladder to get a view, the 3m deep expanse of green water, about the size of half a tennis court, takes your breath away. At the side, giant taps spew water as the supply circulates.

“When we brought schoolchildren down here to see it they were absolutely blown away,” says Bradford Council’s economic development manager Shelagh O’Neill. “People only see the dressing on the surface, not what makes it all work.”

Stephen Sheikh, custodian and warden at the park, indicates a series of pipes which can top up the water supply from a 230m borehole.

“It is sometimes a bit noisy down here, but such an interesting place to work. I’m very lucky,” he says. Stephen will perform basic maintenance as well as making regular checks to ensure there is no bacteria in the water and the pool is free of hazards.

Those who have worked on the project feel privileged. “I feel very lucky to have been involved from start to finish. You don’t get such a chance very often in life, and in my home city too – I hope people will love it,” says Shelagh.

Adds Jonathan: “We want the park to be a place for people to want to come to spend time. We have noticed that people walking through the city centre are changing their routes to cross it.”