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CHEESMAN RESERVOIR - Wanted: Deep-water diver who is not claustrophobic, has zero problems with isolation, works well under pressure and isn't ashamed to talk like Daffy Duck.
Cowards need not apply.
John Ventress has never authored a want ad, but if he had to his first one would probably look a lot like that. Such is life for the man who's heading up a multi-million dollar repair project currently taking place inside Cheesman Reservoir.
"This is a mindset. It's not for everybody," says Ventress who works for Seattle-based Global Diving and Salvage. "You have to be able to deal with things and not let things bother you."
Since August, divers with Global Diving have been working on repairing and replacing the dam's century-plus old valves at depths that sometimes take the divers nearly 200 feet below the surface of the reservoir.
"When they built the dam 110 years ago," says Ventress, "the valves were built into the dam, so they just can't shut off the upstream side of the tunnel."
The new repairs should be done by the middle part of November.
"This dam was quite the feat of engineering for the turn of the century," says Denver Water's Brian Daniels.
But time has caught up to the old dam, he says, and Global Diving offered up the best possible solution. It's a solution that has divers in the water 20 hours out of every day.
"I'm a certified rescue diver, but this is just a different deal," says Daniels.
For 28 days straight, four divers live inside of a highly-pressurized and rather small tube that rests on the top of a barge that floats on top of Cheesman Reservoir. Working in two-person teams, the divers spend about 10 hours a day in the water working on repairs.
When we went out to visit with them, the divers were working at a depth of 195 feet. The pressure down there is roughly the equivalent of nearly 6 atmospheres.
At that depth, the divers must breathe in mostly helium. The air we breathe in is mostly nitrogen, but at that depth, the pressurized nitrogen would lead to nitrogen narcosis. In that kind of environment, divers would be working on a "fuzzy" mind.
"Helium is an inert gas, so it doesn't affect us, where with nitrogen at depth you get a narcotic effect," says Ventress.
The 28 day shifts enable them to limit the number of times the divers must have to go through decompression, time that is considered "wasted time" for skilled divers. Even still, divers working at depths of close to 200 feet have to decompress for approximately 66 hours before they can safely breathe air at the surface.
"You have got to have your mind in the right spot," says a smiling Jimmy Giessler, a diver for Global Diving. "This is enough to drive anyone bonkers in here."
Global Diving has worked on projects from the Gulf of Mexico to the waters off of Alaska. The repairs at Cheesman represent phase one of a two-phase project that should be completed by the middle part of next year.
(KUSA-TV © 2010 Multimedia Holdings Corporation)
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