London 2012 - Alpine stream comes to summer Olympics
Replicating the force and fury of an icy mountain stream on the artificial white water course prepared for the London Olympic slalom canoeing competition requires 13,000 litres of water a second.
Enough, according to calculations at the Lee Valley White Water centre, to fill 75 bath tubs a second or flood an Olympic sized pool in little over three minutes.
"We are trying to replicate an Alpine river," centre manager Simon Ricketts told Reuters.
"From an athlete's point of view, this is probably one of the hardest rivers where a slalom would be held in the world at the moment."
Slalom canoeing, where contestants must negotiate a canoe or kayak along rapids between gates consisting of one or two poles hanging from a wire, is one of the more spectacular and physically demanding Olympic sports.
It was introduced to the Olympics at the 1972 Munich Games where the West Germans had built an expensive artificial course at Augsburg. On the other side of the Berlin wall, East Germany constructed a perfect copy in Zwickau and went on to win all four events in Munich.
The event then disappeared from the Olympics until 1992 when it was reinstated in Barcelona. It has featured at each Games since.
Intriguingly, each successive course has been a modification of the previous design.
"Each time we build a new one it evolves," Ricketts said.
"It's refined, they look at how the previous course was built, the challenges that are there for the athlete, the way the water flows, the obstacles that are in the course.
Ricketts said the "stoppers" on the course at the 2008 Beijing Olympics, where the surface water rolls back at the paddler at an obstacle, had been huge.
"It meant that the momentum and the weight of the paddlers who were very heavy and very muscular carried them through the stoppers while some of the slight but very skilful paddlers were at a disadvantage because the stoppers would stop them dead," he said.
"So here we are trying to be as fair as we can, there are stoppers at a level that are fair to all athletes. It's about making sure that those who are very skilful but a bit more slight are able to compete on a level playing field."
Ricketts, 40, who represented Britain as a sprint kayaker at a junior level in 1989, said white water contestants were supremely fit athletes.
"The guys are training twice a day on the water at the moment, they're in the gym, they're running," he said. "Our paddlers are very fit and strong athletes. They have very good strength-to-weight ratio, they're very strong in comparison to their weight."
Shaun Dawson, chief executive of the Lee Valley Regional Park Authority which is responsible for the centre, said the 12,000 tickets for each day of competition during the Olympics had all been sold.
"You get close, it's fast and furious," he said. "It takes incredible skill not to touch the bars that hang down and at the same time you are up against the clock.
"It's a very fast energetic sport, a lot of skill and strength is required and that's what's very attractive about it."
Dawson said canoeing was the fastest growing water sport in the United Kingdon with 1.2 million participants across all forms.
He said the centre was the first Olympics venue to secure a major legacy event, the 2015 world canoeing championships.
"The big work starts in April," he said. "The stands for example. We hand over to the London organising committee in April on a venue-hire arrangement. We get the venue back in early September."
The Olympics run from July 27 to August 12.