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Damming the Mighty Mississippi

Jason Parrott

The 100th anniversary of the completion of the dam that spans the Mississippi River between Keokuk, IA and Hamilton, IL will be celebrated June 27-30.

Thousands of visitors, from near and far, are expected to attend the four day event, which will include trolley rides across the dam and tours of the nearby power plant.

The series "Damming the Mighty Mississippi" takes a closer look at how the dam was built, 100 years ago, and its impact on the region, both in 1913 and today.

Part 1 : The Right Man for the Job

Author John Hallwas said the idea of actually building the dam drew a negative response in the late 19th century.

Credit Mississippi Power House Museum
Hugh Cooper

"Damming the Mississippi River was actually used as a metaphor in the 19th century for 'you can't do that,'" said Hallwas.  "Like, 'you can easily do that as you can dam the Mississippi River.'"

Hallwas, who wrote the book, Keokuk and the Great Dam, said a group of men started to think beyond that statement in the late 1800's when they formed the Keokuk-Hamilton Water Power Company.

Hallwas said the members lobbied the federal government for permission to build the first dam across the Mississippi River, which was granted by Congress in 1905.

That left one last challenge for the Keokuk-Hamilton Water Power Company: finding someone willing to do the impossible and build a dam across the Mississippi River.

they... decided that he was the man they wanted

Hallwas said the name, Hugh Lincoln Cooper, surfaced in late 1905.

Credit Rich Egger
John Hallwas

"Cooper was a self-taught engineer who was born in 1865 in a small town in southern Minnesota," said Hallwas.

Hallwas said Cooper was a brilliant man who started out designing and building railroad bridges before moving on to power plants, including one at Niagara Falls in Canada.

Mike Foley, who serves on the Mississippi River Power 100 Committee, said that project put Cooper "on the radar" of the Keokuk-Hamilton Water Power Company.

He said several men from the area even traveled from Keokuk to see the Niagara Falls facility, which included the construction of a giant piping and turbine system built into the rock beneath the falls.

Credit Jason Parrott
Mike Foley

"So when they saw that and saw what (Cooper) had done," said Foley, "they probably decided that he was the man they wanted."

It turns out Cooper not only had to design and build the dam, but he also had to find investors because Congress did not fund the project.

Foley said years went by and the millions of dollars needed were still in question, that is until a few weeks before a deadline to start construction that was set by Congress.

"Cooper had heard that there might be some investors out east," said Foley.  "He traveled out there and telegraphed back a few days later, 'I have the money, start digging.'"

That telegraph meant crews could start doing the impossible.

Part 2 : Building the Impossible

On-Air Version of Part 2

Engineer Hugh Cooper seemed to understand the significance of the project, having hired writers to send articles to newspapers and magazines and a photographer to document the construction.

Credit Mississippi Power House Museum
A group of men digging a trench at the start of construction of the 1st Mississippi River dam.

Mike Foley with the Mississippi River Power 100 Committee said the first photograph was taken in January 1910.

"(The photographer) got a picture of ten men with shovels digging a trench and that is how they started," said Foley.

Foley said 1910 was devoted to site preparation, so the workers had everything necessary to build the dam: rock crushers, cement mixers, bunkhouses, etc.

They would pump out the water, and... dig down until they got the rock to the proper place

He said the first half of 1911 was spent on dry land as crews built 1/3 of the dam in a cornfield while the second half was spent in the river.

Credit Mississippi Power House Museum
Crews installing the coffer dams during the construction

Foley said they built and installed large, wooden coffer dams, which were filled with rock, to hold back the Mississippi River while they worked.

"They would pump out the water," said Foley, "and once they got it dry, they could dig down until they got the rock to the proper place.  Sometimes, they would have to drill holes and drop dynamite in and blow it up until they had it to the level they wanted so they could pour foundations.”

He said one of the most exciting pictures on display at the new Mississippi River Powerhouse Museum in the River City Mall is of the men working with water rushing under their feet, trying to get the last of the coffer dams in place.

There were challenges along the way, inlcuding severe flooding in 1912 that Foley estimated reached the level of the record-setting Flood of 1993.

Credit Mississippi Power House Museum
Crews trying to protect the construction site from the rising Mississippi River.

“They really thought they were going to lose the coffer dam so they put some dynamite in place," said Foley.  "They were going to purposefully blow up a small section so they would not lose the whole coffer dam.”

Foley says there was even one night when hundreds of men raced from the bunkhouses to the construction site with shovels and sandbags to protect the coffer dams.
There was also tragedy along the way as several dozen workers died from accidents during construction.

Foley said Cooper was able to complete the project on-time, in 1913 and under budget because of his innovations, including the largest cranes in the world, on-time materials delivery and new tools.

Part 3 : How It All Works

On-Air Version of Part 3

Credit Jason Parrott
Plant Superintendent Larry Weiman

The dam and the nearby power plant, which are both owned by Ameren Missouri, work together to create hydroelectric energy.

Plant Superintendent Larry Weiman said contrary to popular belief, the water passing through any of the 119 arch-shaped openings in the dam has nothing to do with power generation.

I think our power plant, typically, is considered to be able to power 75,000 homes

He said that water is instead being released to maintain the river level north of the dam, per the U.S. Army Corps of Engineers.

"What we want to do is pass everything through the plant," said Weiman.  "If there is more than that, we have to open gates to pass it through the dam so we maintain the pond at its current elevation."

Credit Jason Parrott
Water rushing through the dam

Weiman said the power is generated by the water passing through the plant, from west to east.

The water passes through a series of gates, screens and chambers before going "over a cliff" towards 15 giant turbines located beneath the eastern half of the plant.

Weiman said the "cliff" is actually the difference in water levels north and south of the dam.

"The design here is for a 32' differential between the pond and the tailwater," said Weiman.  "If those conditions are optimal, we would get into the area of 38'"

Credit Larry Weiman
TSPR's Jason Parrott (who is 6' 6") standing in front of one of the old turbines.

Weiman said the turbines will spin at a set speed, so as more water is allowed to fall through them, they produce more energy trying to maintain that speed.

The turbines, which each weigh about 100 tons and measure more than 20' in diameter, are connected to large generators inside the plant.

Weiman said his best guess is that the 140 megawatt facility, which is one of Ameren Missouri's smallest and oldest, could power a small city.

"A lot of it depends on if you are just talking about homes or industries or businesses," said Weiman.  "I think our power plant, typically, is considered to be able to power 75,000 homes.”

Ameren Missouri Consulting Engineer Dave Ostrander says another misconception is that the plant is producing power only for the city of St. Louis.

He says, in fact, the power produced simply enters Ameren Missouri's grid, so it is impossible to tell where it is going or what it is powering.

Part 4 : The Impact of the Dam

On-Air Version of Part 4

Mike Foley, who serves on the Mississippi River Power 100 Committee, has been researching the construction of the dam for the last 18 months.

It made travel up and down the river just as easy as it is today, so that had an enormous impact

Credit Mississippi Power House Museum
The drawing Mike Foley refers to about the "skyscrapers" of Keokuk

During that time, he found a drawing that stands out to him as a vision of what people though the dam would do for the city of Keokuk.

“What they did was take the tallest building in Chicago and added about 5-6 stories to it and filled the shoreline with these skyscrapers," said Foley.  "They really believed this was such as beautiful project that Keokuk was going to grow to become a little Chicago."

That never happened as Keokuk's population never exceeded 17,000 while Chicago had about 2.2-million people at the time.

Keokuk did gain several local industries, but it never realized those skyscrapers from the drawing.

Foley said one thing the dam did do was put Keokuk on the map.

"Popular Mechanics magazine, every month, had at least two pages dedicated to the building of (the dam)," said Foley.  "The New York Times, the Chicago (Tribune and Sun Times) all ran articles constantly about the progress of this great dam across the Mississippi River.”

John Hallwas, who wrote the book, Keokuk and the Great Dam, said the dam also accomplished the initial goal of the Keokuk-Hamilton Water Power Company, improving river transportation.

“It ushered in a new era for America’s greatest river," said Hallwas.  "It made travel up and down the river just as easy as it is today, so that had an enormous impact.”

Fast forward 100 years and Keokuk Mayor Tom Marion said the dam provides another benefit to the area: tourism.

Credit Jason Parrott
Ameren Missouri's power plant

"You can visually see it and you can watch a boat lock through and things like that," said Marion, "so from our standpoint, it is tourism.  I saw a family, the other day, they were getting ready to cross the bridge when they saw the dam.  They stopped and got out (of their car) and stood with their backs to the dam and the powerhouse and took a family photo.”

The tourism aspect will expand greatly during the four day celebration of the completion of the dam.

Local organizers expect 15,000 - 20,000 people to visit Keokuk and Hamilton to participate in a wide range of events, a schedule of which is available here.

If you would like to view a slideshow featuring more photos from the dam; listen to full interviews with- John Hallwas, Mike Foley, and Larry Weiman; and watch a short video of water leaving the dam, please click here.

Jason Parrott is a former reporter at Tri States Public Radio.