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Copyright
2011 Rocky Mountain Rider. ALL RIGHTS RESERVED. Reproduction of any
editorial material, artwork and photos is strictly forbidden without
express written permission of the publisher. For information about
reprint rights, please contact the editor; editor@rockymountainrider.com.
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Old-Fashioned
Horsepower & Ingenuity
Rebuilding
Mill Creek Dam
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By
Natalie Riehl
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August
2006 Issue
[Editor’s Note: We originally ran
this article in 1993, and are re-running it again due to the controversy which
has sprung up in our
Bitterroot
Valley
of western
Montana
.
Some of the dam owners, who
must adhere to current dam safety laws and standards, believe they can only use
mechanized equipment to repair the aging dams. Other dam owners and Forest
Service officials believe the dams can be strengthened by a combination of
modern equipment and old-fashioned horsepower.]

Yerian
manufactured and then built a boom to haul heavy rocks up the side of the dam
with one of his team.
The Problem: Mill Creek Dam, built in 1912 to hold irrigation water,
is crumbling due to damage by erosion and avalanches.
The Complication: This dam is thirteen miles into the mountains of
the Bitterroot Wilderness Area in western
Montana
. No power equipment of any kind is allowed in U.S. Wilderness areas.
The Project: A four-man team, headed by draft-horse expert Don Yerian,
rebuilds the dam utilizing Yerian's skills, plus those of master stone mason,
Eric Benton.
Construction on the current
Mill Creek Dam was started in 1910 and completed in 1912. It is an awesome
structure: 330 feet long, from east to west, thirty feet high in the center, and
fourteen feet wide across the top. The inner structure is "rubble
rock" backfilled with earth, and the dam's outer walls are 18-inch thick,
dry laid, natural rock. The dam is narrower on the top, and the walls slope
outward toward the bottom.

Yerian
and his team of Belgians scoop dirt to fill the rock dam.
"It amazes me the work people went through to irrigate those rock
piles below so they could scratch out a living," says Don Yerian, a
Bitterroot
Valley
native. "They had to have a lot of determination to make it."
He is talking about the settlers of the late
1800s—his grandfather being one of them—who moved into the Bitterroot and
wanted to farm the arid valley floor. To access the wealth of water in the
mountains to the west, they built a series of dams far up the canyons. Seventeen
dams still exist within the Wilderness Area.
In the Bitterroot, the Yerian family is well
known for their draft horse expertise. Don's dad, Charlie, is still farming with
them at age 73. Don, 46, grew up with them, and prefers to make his living with
his horses rather than mechanized equipment. He uses them for a variety of heavy
work, including logging, thinning timber, repairing dams and flumes, plowing,
and mowing hay.

Dragging
the rock sledge.
When Forest Service engineers determined that Mill Creek Dam needed
significant repairs, they contacted the water users who, in effect,
"own" the dam and are responsible for its maintainance. The dam, of
course, was built years before the Wilderness Act came into effect in 1964. But
now, since it is contained in the Wilderness Area, the water users cannot punch
a road in there to drive in heavy equipment.
Yerian defends the use of horses. He can do as
good a job as any crew with bulldozers—and, when he is finished, he will leave
the high country lake in pristine condition. He will do it all with
hand-tools—crosscut saws, axes, Pulaskis, picks, shovels, wedges,
chisels—and his team of Belgians.
When the water users asked Yerian to bid on the
project, he rode up the thirteen-mile trail to assess the damage. "Bad
snowslides, carrying logs, had come off that west slope and knocked the face
rocks out of the wall. The dam was eroded so badly, it wasn't wide enough to
drive a team down the top of it.
Needing "someone to engineer digging out
the damaged part and re-laying the wall so it looked perfect," Yerian asked
mason, Eric Benton, to go in with him.
"Eric took one look at all those face
rocks, which were at the bottom of the thirty-foot dam and which could weigh as
much as 500-1,000 pounds, and said he was concerned about how we were going to
get those big rocks back to the top. He said he could re-lay them if he could
get them. I told him I could get the material to him."

Leveling
the dirt top of the dam.
Yerian's biggest dilemma was how to haul these monster stones up the
thirty-foot face without power equipment. He designed and built a swing
boom—with a 30-foot-high mast pole and a 20-foot-long boom arm—which he
erected on top of the dam.
"I took the model from an old hay
pull," he explains. "We made the irons heavier. The only difference in
design is that the arm on a hay pull works from the top of the mast, and we
needed the swing at the bottom."
Although he would have preferred to use fir for
its strength, there was none available at that altitude. So he used a lodgepole
for the mast, and a spruce for the boom arm. He split well casing in half to
hold the fittings on log ends, and carefully hewed the logs to fit into the
casing. To steady the boom, he used four guy wires, made of 3/8" cable,
which he attached to the top of the mast and anchored to huge rocks.

Top
of the repaired and nearly finished dam.
The first step in repairing the dam was to dig out the 120-foot damaged
stretch. "We had to dig out the back wall and go down eight to ten feet
before we got to good, solid laid rock." Benton and his assistant, Steve
Fox, then began re-laying the rock and back filling with dirt. Much of the dirt
was brought in on a "slip" from the lake bank and the rubble rock was
brought in on a "stone boat."
Yerian used his team of Belgians—Tye and
Tilly—to pull up the "basket" filled with face rock from below. The
average weight of rocks in the basket was 500-600 pounds, but attached to the
three-way pulley system, the burden on the horses was much reduced.

Nearing
completion, the dam is a work of art.
The project took 25 days. When they finished, Yerian calculated they had
moved 1,900 cubic feet of rocks and dirt out, had refilled the 1,900 cubic feet,
and had laid 1,000 square feet of face rock.
Yerian hired a packer, with a string of nine
mules, to pack in all the equipment and supplies. "He made five trips
in—bringing in hardware for the boom, horse feed, grub, tents, hand tools, 500
feet of cable, and bolts—and one trip out. We went through "$1,200 worth
of groceries," recalls Yerian, "and had the best eating a man could
dream of. Steaks, hamburger, bacon, eggs, ham. Lots of fruit. Drank a lot of
Gatorade."
Yerian has been nominated for the U.S. Forest
Service's prestigious "Silver Axe Award." It is given annually to a
crew who has completed a difficult construction job using only tools from the
turn of the century.
Before Yerian began the project, the water
commissioners told him, "We're relying on you. This is all your deal."
Yerian accepted the challenge, and without a
single power tool, reconstructed the Mill Creek Dam.
The finished dam looks like a perfect castle
wall. Square on top, it is now sound and safely holds back the 42-acre (780
acre-foot) reservoir that serves 177 users on 2,219 acres of land.
For more information on the issue of irrigation dams in USFS Wilderness
Areas, contact Terri Anderson, Engineer with on the
Bitterroot
National Forest
; 406-363-7161.
[Don
Yerian is one the 2006 inductees into the Montana Teamsters Hall of Fame. Be
sure to read our article in the November 2006 issue which introduce readers to
all of the inductees.]
Copyright
2011 Rocky Mountain Rider. ALL RIGHTS RESERVED. Reproduction of any
editorial material, artwork and photos is strictly forbidden without
express written permission of the publisher. For information about
reprint rights, please contact the editor; editor@rockymountainrider.com.
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