This photo is of one of the many tunnels in Dworshak Dam’s interior. With pumped in air to breathe, maintenance workers walk on a narrow concrete pavement. Sometimes one has to step over stalagmites on the flooring and above one’s head stalactites hang. The mossy granite walls display holes that were drilled for explosives. Many of the plugs taken from the holes are now in a pit at Dworkshak Fish Hatchery below.
By Alannah Allbrett
A huge lichen-covered boulder guards the entrance; moss and
ferns grow beside the mysterious portal. Granite surrounds us as we step into
the dank tunnel with a noticeable aroma somewhat like a fishy/earthen basement.
A string of dim lights, like dusty pearls, precedes us as we descend along a
narrow concrete walk with water on either side of it trickling along the
granite facing. I reach out at one spot to touch the wall and pull my hand back
quickly from the squishy, wet surface. I guess I wasn’t expecting my fingers to
sink into the green ooze.
I am reminded
to ‘watch my step’ as we gingerly step over the occasional green slick area. Periodically,
a cold droplet of water smacks me on top the head just to keep me humble. I,
with my guide, Lead Park Ranger Deb Norton, am being lead to what looks like
Gollum’s [of Lord of the Rings fame] cave.
We walk for
what seems like a quarter of a mile, to where the pathway takes a sharp turn right,
and we proceed, ever downward. I hear water dripping, echoes from my own
questions, and the sound of a blower Deb turned on that provides air to
would-be travelers to the nether regions. I am on a mission to view what only a
handful of people ever see – the diversion tunnel of mighty Dworshak Dam, the
highest straight axis, concrete gravity dam in the U.S. and the states’ third
tallest dam (as opposed to Hoover Dam which is curved or arch gravity dam).
The
diversion tunnel was built before the dam, by blasting through solid granite,
to make a passage for the clear, pure waters of the North Fork
of the Clearwater River, known to locals merely as the North
Fork. The headwaters of this magnificent river begin in the Bitterroot
Mountains, along north central Idaho’s
Montana border, and flow 135
miles and are captured behind Dworshak.
I am using
the handrail, mainly because I don’t want to make an idiot of myself by tripping.
Deb is used to this kind of thing and marches confidently before me. We keep
going downward, and I make a mental note to myself to try to keep up on the return
to daylight and outside air – I know it’s going to be like being on an inclined
treadmill machine. She assures me that her knees are younger than mine – how
does she know that? I wonder as I puff along.
As we get
to the bottom, I look upward and all around me as I stand at a guardrail, over
what appears to be water. I’m not quite sure. The water is so clear I think I’m
looking at the ground floor of this immense cavern in which one could put an
airplane or two.
This is it!
I am officially in Gollum’s cave. Look there’s his boat – a little two Hobbit
craft tied up at the dock. Though we have an electric light above us, the light
gets lost in here – it fades off into the distance and gets swallowed by the
walls which know it doesn’t belong. The light and we are intruders in the belly
of some huge beast.
I strain my
eyes to try to see into the far reaches of blackness. Deb points out the water
below and says that with no current, it stays crystal clear. This is the place
where engineers rerouted a whole river so that they could construct the dam;
the water had to go somewhere. They keep the boat there so they can inspect the
tunnel and follow it end-to-end for any maintenance that might be needed.
It’s time
to leave, and Deb turns to go back up the passageway the way we came in; I take
one last look knowing I will probably never return here again.
Over my
shoulder, it turns black inside the cavern. “I didn’t do it” says my guide. The
lights are obviously on some kind of timer or motion detector – who knows? But
it’s black in that hole, that much I can say for sure. We have, of course, the
lights along the walkway which show the pathway back to the entrance. Gollum’s
sanctuary and secrets are safe once more from intruders into this quiet place
that time has forgotten – the place where men sweated, set dynamite caps,
removed acre feet of rock, risked their lives – all so that a dam could be
built.
The
building of Dworshak, would also build-up the little logging town of Orofino
that hosted hundreds of workers with their families, taught their children in
school each day, the town that expanded in every way to encompass the
construction of this massive structure which was dedicated in 1973 to Henry
Dworshak (1894-1962), an Idaho State Senator who was very helpful in finding
funds for the project.
My tour
includes standing atop the dam, looking out across the huge reservoir, looking
down the face of the structure, and on down the canyon ravine where the river
is the delight of fishermen who come to the “steelhead capital of the world.”
Speaking of fisherman, Deb points toward the base of the dam and tells me ‘x’
number of people are fishing down there on “Fisherman’s Wall.” I don’t see any
– not a one, until she points out what appear to me to be fence posts. The
height of the dam, at 717’ high, is deceiving. It really doesn’t seem like that
far down until one mistakes human beings fishing as fence posts, then one
realizes that this is one BIG puppy of a dam.
As a child,
my father was a dam keeper in Oregon,
where I spent an enterprising summer selling grasshoppers as bait to the
fishermen there. Each morning, at 4:30 a.m.,
my dad radioed the water measurements to the dam below us. He would be told the
amount to lower or raise the dam gates – which he did by hand, cranking them
manually. This ain’t that!
Dworshak can
hold 3 ½ million acre feet of water at “full pool” when the reservoir is at its
highest. Each acre foot is similar to a football field filled with one foot of
water. And, if you aren’t impressed by that, there is enough concrete in this
concrete gravity dam to build a sidewalk 5” thick and 36” wide around the world
at its fattest part – the equator.
As my guide
and I drive across the top of the dam to what’s known as the North
Tower, the way ahead is blocked by workers’
vehicles. Apparently there is some kind of problem with a pipe that supplies
water to Clearwater Fish Hatchery below which – gets the water – to grow the
fish – that fill the waters – that bring the fishermen/women – to take home the
fish – for smoking, or trophies – that hang on their walls – that come from the
house that the Corps built. So, Deb stops her vehicle and proceeds to make a
five point turn – it’s on top of a dam after all – it takes a little
maneuvering.
Deb takes
me inside the tower that houses an interesting exhibit. It is nearly a floor-to-ceiling
glass-fronted display case (8’ x 15” diorama) with a mock-up miniature display
of the dam site under construction. Someone had the smarts to construct this
instructional replica which I wish everyone could view. In order to supply the
concrete, an onsite quarry had to be built first. After rock was blasted free,
it was loaded into dump trucks and hauled to a hole called the “Glory Hole”
where it was put into a rock crusher.
The rock
crusher was able to reduce four foot boulders into six inch fragments at the
rate of 2,000 tons per hour. Without going into a lot of statistics, the
crushed rock went into Dworshak’s own concrete plant. The first bucket of concrete
was poured on June 22, 1968,
and the last on January 26, 1973.
The dam is the largest one ever constructed by the U.S. Army Corps of Engineers,
which maintains it today.
Come back
next week, as Paul Harvey used to say for, “the rest of the story,” wherein we
continue my tour, include the Visitors’ Center, and hit you with more fun facts
about one of the most amazing structures in North America – Dworshak Dam.
A lichen covered boulder stands sentry duty at the entrance to Dworshak’s Diversion Tunnel which was built prior to the dam to divert the waters of the Northfork of the Clearwater River.
Just inside the entrance to the Diversion Tunnel, one meets with a biosphere of live ferns growing in the cave like interior.
The “Glory Hole,” as it was called, was constructed to drop broken rocks into the rock crusher below. The rock crusher was capable of reducing four foot boulders into six inch fragments at the rate of 2,000 tons per hour.
In a picture, dated June 22, 1968, dignitaries drop the first official bucket of concrete, beginning the construction of Dworshak Dam in north central Idaho. The dam was completed in January of 1973. It took four one-half years of pouring concrete continuously 24 hours a day, seven days a week, averaging 10,000 cubic yards per day to complete this massive project.
A look upward at Dworshak’s spillway. The dam’s height at 717’ is deceptive. People at the bottom look like tiny little twigs. The width of the dam across the base is 550’ and houses an elevator, and many hallways and tunnels.
This photograph shows the Diversion Tunnel under construction. Air lines went in to operate the jack hammers.
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