Amana Millrace Restored After '93 Flood Damage
Posted on: Tuesday, 1 May 2007, 18:00 CDT
By Dave DeWitte, The Gazette, Cedar Rapids, Iowa
Apr. 29--AMANA -- The hum of a hydroelectric turbine that lay silent for 14 years will liven up Amana's Maifest this year.
The Amana Colonies have entertained millions of visitors since 1993, but few of them knew that one of the town's most cherished historic treasures was on sick leave.
Amana's 6.5-mile millrace provided mechanical power and later hydroelectric power to the community over a span of 124 years.
It provided mechanical power to the Amana Woolen Mills at Main Amana and Middle Amana, and the Amana calico mill at Middle Amana.
Fed by the Iowa River, the millstream also was a source of beauty, a place for recreation, and a home for wildlife.
Then, the torrential rains of 1993 caused the Iowa River and the millrace to swell beyond their banks. Flooding weakened levee walls so badly that if the operators had allowed enough water to power the hydroelectric turbine into the millrace, it would have blown out the levee walls and flooded nearby properties.
"In 1993 it was closed, and the decision was made that it would be a temporary shutdown," said Laura Hoover, executive director of the Amana Colonies Historic Sites Foundation. "We didn't think that meant 14 years."
The length of the renovation period was because of the difficulties of raising the needed funds, roughly $1 million. The last crucial piece arrived last year in the form of a $295,000 National Park Service grant.
The money, Hoover says, paid mainly for dirt.
"It surprises the living daylights out of you when you find out how much good-quality dirt is worth -- thousands of tons of it to reinforce the levee walls," Hoover explained.
The millrace had been owned and overseen by the Amana Society Service Co., the community's electric utility, before the flood. Afterward, the service company realized it would never come up with the money to repair the millrace. The millrace and hydroelectric turbine were turned over to the Amana Historic Sites Foundation, which had access as a non-profit group to government grants.
Hoover, formerly of the Amana Colonies Land Use District, was hired about seven years ago to move the project forward.
Everyone in the Amana Colonies recognizes the historic significance of the millrace, Hoover says. In its day, the millrace was a technological marvel. Not one engineer was involved in the design of the project, and yet the water falls only one foot between the Iowa River and hydroelectric dam, where it drops only two inches. The design was highly efficient in preserving the water's velocity to move the plant's turbine.
"Shive-Hattery, our engineers on the latest portion of the project, have been stunned repeatedly at how well it was done," Hoover said.
The hydroelectric turbine has been at its present location on the millrace since 1954, said Terry Hershberger, general manager of the Amana Society Service Co.
The turbine had been overhauled the year before the 1993 floods put it out of commission.
When time came to restore water flow and reactivate the turbine last month, it needed only a little lubrication and cleaning.
Although the turbine is rated to produce 300 kilowatts of electricity, it has never produced more than about 250 kilowatts because of flow conditions in the millrace.
The historical foundation presold the hydro dam's output over the next few years to the Amana Society Service Co. to raise revenues for repairs.
Hershberger believes the dam will provide an output of 150 to 200 kilowatts, enough electricity to power a few dozen homes at most.
Such "low-head" hydroelectric projects are becoming more popular with municipal utilities in Iowa's river towns, many of which have old inactive hydroelectric dams.
"With the way the renewable energy thing is going, there's been more of them reactivated, and some that have been down for more than 50 years," said Eric Stoll of the Iowa Association of Municipal Utilities.
They don't attract the attention of wind power because of their limited and variable power output, which is linked to flow conditions, and lack of federal tax credits.
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Source: The Gazette - Cedar Rapids, Iowa
User Comments (1)
| 1. |
Posted by Tony May on 09/10/2007, 11:00 Great update on what the hydro-electric plant at Amana was and the restoration after the horrid Iowa flood of '93. |
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