Hoover Dam's backside stretches more than 700 feet from top to bottom, but the dam's seeing trouble from the tiny aquatic zebra mussel. (Photo by Shawn Allee)
Hoover Dam generates some of the power that lights Las Vegas all night long. But there’s something
that’s making that job a bit more difficult. Shawn Allee found out, it’s a tiny aquatic pest:
Transcript
Hoover Dam generates some of the power that lights Las Vegas all night long. But there’s something
that’s making that job a bit more difficult. Shawn Allee found out, it’s a tiny aquatic pest:
The usual tour of Hoover Dam starts at the visitor’s center – way at the top.
Robert Walsh works with the federal agency that runs Hoover.
He says, go ahead – look over the edge.
Allee: “OK. That’s creepy. Seriously, that’s creepy.”
Walsh: “It’s spooky. Are you afraid of heights?”
Allee: “No, they don’t bother me at all.”
The dam stretches down 700 feet, and it holds an enormous reservoir – Lake Mead.
This tour is awesome, but Walsh says there’s another tour, too.
It’s, um, NOT so awesome.
It’s all about the trouble the tiny quagga mussel is causing Hoover and other nearby dams.
To get that tour, Walsh takes me to Leonard Willet.
Allee: “Where are we right now?”
Willet: “It’s kind of a work station where all the quagga mussel control activities take place
for Hoover Dam.”
Allee: “It’s quagga mussel central for this area?”
Willet: “Exactly.”
Willet first heard quagga mussels were growing in the nearby Lake Mead reservoir in 2007.
He called an expert for advice.
“First thing out of her mouth was, ‘I’m sorry to hear that.’ I knew it was a lot more serious.
And I asked her what we’re in for.”
Willet learned quickly enough – quagga mussels attach to nearly anything underwater.
He shows me a sandal that was in water – and is smothered in them.
They’re like clams the size of your pinky fingernail.
“We went from zero to THAT in seven months.”
And that’s the problem.
Hoover Dam uses water from Lake Mead to spin generators.
The water moves around in pipes – and quagga mussels can attach to them – just like on that sandal.
Allee: “What does that mean in a real practical sense?”
Willet: “Our intake towers would close off. Once you start closing off, you can’t spin the
generators. That’s just kind of the big view of it.”
Zero power generation.
That’s the worst-case scenario. It hasn’t happened – but it’s a fight to prevent it.
“Now, we’re going to go down to the third floor, which is the generator floor.”
The generators are inside broad metal cylinders.
Big water pipes turn the generators. Smaller ones cool them off.
“Well, we circulate cold water from those pipes. If those start to plug up with mussels, then
you can’t keep a generator cool, if those … it shuts down due to overheating.”
Right now, it takes a lot of scraping to keep everything clear.
All this effort’s adding up – Willet says he’ll spend 2 million dollars soon on new equipment.
Even with that, Willet is still a bit jittery about some pipes outside, at the very bottom of the dam.
“The one that’s probably the scariest of all is, we have a fireline that runs around here.
Mussels love it. Then, your firelines, when they’re needed, are plugged with mussels. So
that’s another area you have to really be careful of, safety-wise.”
This didn’t have to happen.
Quagga mussels invaded eastern rivers and the Great Lakes first.
Experts figure the mussels hitched a ride West on someone’s fishing boat.
Apparently – someone didn’t clean their boat properly – and mussels dropped into Lake Mead.
Allee: “When they built this amazing structure during the Depression, do you think they had
any idea that something like this could ever happen?”
Willet: “I think there was a lot of disagreement among professionals that a little mussel the
size of your finger nail could impact a large hydro facility, but we’re quickly learning a bunch
of them can impact water and power delivery.”
Willet says if boaters aren’t careful – they’ll spread quagga mussels to the Pacific Northwest, where
there’re lots of dams and hydro power plants.
After all, if it can happen at mighty Hoover Dam – it could happen anywhere.
For The Environment Report, I’m Shawn Allee.