Dworshak
Dam
Location:
Dworshak Dam is located on river mile 1.9 of the North Fork
of the Clearwater River, just outside of the city of Orofino, Idaho.
History:
The U.S. Army Corps of Engineers began construction of Dworshak
in 1966. It first became operational for flood control in 1972 and
the powerhouse went online in March of 1973. The dam was named after
Henry Dworshak, a U.S. Senator for Idaho. There are 3 power-generating
units at Dworshak, and the Governor authorized 3 more in 1990. However,
controversy halted the expansion project. Currently, Dworshak is
only producing half the power originally projected, even though
the generators have been installed. Peak loads would cause such
a flood downstream that a second dam would have been needed at Lenore.
Due to citizen opposition, the second dam was rejected, and the
Governor revoked the authorizations for generator numbers 4, 5 and
6.
Statistics:
The storage capacity of the reservoir created by the dam is 3,453,000
acre-feet. It is 53 miles long extending into the Bitterroot Mountains.
The total power output from the dam is 380,000 kilowatts. Unit one
produces 200,000 kilowatts, while units two and three both generate
90,000 kilowatts apiece. Dworshak is a straight axis gravity dam
at 717 ft. in height with a crest length of 3,287 ft. The total
cost to build the dam was $312 million. There is twice as much concrete
in Dworshak Dam as in Cheope’s Great Pyramid in El Giza, Egypt.
Interesting
Facts:
Dworshak is the tallest straight axis gravity dam in the Western
Hemisphere and is the third highest dam in the United States. It
is the 22nd highest dam in the World.
In
June of 1980 the dam developed a leak through a 236-ft. long crack
on the reservoir side. 7700 gallons per minute of water was sprayed
past the powerhouse down into the river. The cost to fix the leak
exceeded $1 million. The U.S. Army Corps of Engineers drilled seventy
holes into the dam to intercept the crack, relieving pressure on
the dam. A plastic sheet was then lowered over the crack. This reduced
the flow by half. Additional repairs including a patch made of sawdust,
cement and volcanic ash further reduced the flow to an acceptable
level.
Controversy
surrounded the construction project from the outset. Says Cort Conley
in Idaho for the Curious, "There have always been more
politicians than suitable damsites. Building the highest straight
axis gravity dam in the Western Hemisphere, on a river with a mean
flow of 5,000 cubic feet per second, at a cost of $312 million,
in the name of flood-control, is the second-funniest joke in Idaho.
The funniest joke is inside the visitor center: a government sign
entreats, "…help protect this delicate environment for future
generations."
"The
North Fork of the Clearwater was an exceptional river with a preeminent
run of steelhead trout, and the drainage contained thousands of
elk and white-tail deer. The Army Corps of Engineers proceeded to
destroy the river, habitat, and fish; then acquired 5,000 acres
for elk management and spent $21 million to build the largest steelhead
hatchery in the world, maintaining at a cost of $1 million dollars
a year what nature had provided for nothing."
The Dworshak Dam has a Visitor's Center; check with the Corps for open hours.
The
Dworshak National Fish Hatchery at the southeast end of the North
Fork Bridge at Ashahka is open during daylight hours, and visitors
can take a self-guided tour.