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PRAIRIE DU SAC — Denman Kramer never kept a tally of the times he’s gone up and down the 24 steps that lead from the parking lot entrance to the main office on the second floor of the dam here.

If there was a log book for such measurements, it would include thousands of entries. But last week, Kramer, 95, who retired in 1980 as the Prairie du Sac Hydroelectric Dam’s supervisor, looked spry as he eagerly climbed the steps, a cane in his right hand.

“It’s a lot of times,” Kramer said, when asked about his stairway trips. “It tickles me to think I can still do it.”

This is where, for more than 40 years, Kramer maintained the dam’s eight hydro-turbines and eight generators. He raised and lowered the dam’s 41 tainter gates and measured the flow of Wisconsin River water through the dam that, on an average day, totals 5.8 billion gallons.

Few people know more about the 100-year-old dam and its history than Kramer. But an ongoing exhibit at the Tripp Heritage Museum in downtown Prairie du Sac and the first public tours of the dam in more than a decade will shed light on the dam’s construction, its inner workings and role in the economic and social fabric of the region.

The dam, owned by Wisconsin Power & Light Co., a subsidiary of Alliant Energy of Madison, can generate enough power each day for up to 30,000 homes. The dam also created Lake Wisconsin, a popular recreation area for boaters, anglers and nature lovers. In addition, the dam made this section of the river one of the best spots in Wisconsin to view bald eagles in the winter. The water remains open below the dam year-round and offers a prime fishing spot for the majestic birds who number in the hundreds. Tourists come by the thousands.

“We have pictures in our collection of the river freezing pre-dam. When the dam was created, you have this open water, pretty much from here on down,” said Jack Berndt, manager of the museum that is operated by the Sauk Prairie Area Historical Society. “The creation of Lake Wisconsin, if you go back 100 years, takes the whole farmland piece and it sort of changes that. It created places like Gruber’s Grove, Wiegand’s Bay and you have the whole tourist and resort kind of lifestyle that sprang up because of the dam.”

In reality, those amenities were results of the dam, not the reason for the structure.

The dam was built to generate electricity at a time when electricity was growing in demand but many rural homeowners were still off the grid. In fact, the dam struggled financially in its early years and sold much of its power to customers in Milwaukee.

According to historical documents, the dam’s power wasn’t used for local markets until 1916 after its builder, Magnus Swenson, sold the dam and another he had built a few years earlier up river in Kilbourn City, now known as Wisconsin Dells, to John I. Beggs. It was Beggs who expanded the markets for the two dams by extending electricity to Sauk City, Prairie du Sac, Baraboo and Mazomanie.

“Technologically it was a success but economically they had their problems,” Kramer said.

The dam’s construction was an epic undertaking and hampered by the unpredictability of the river.

Work began in January 1911 and during the three-plus years it took to build the $1 million facility, several setbacks occurred and delayed completion by a year. In the fall of 1911, high water destroyed the temporary train trestle used to haul construction materials to the site, wrecked wood pilings for the spillway foundation and destroyed part of the coffer dam that was built around the partially completed powerhouse. In the spring of 1913, ice jams destroyed the trestle, scores of pilings and a barge carrying a sand pump.

The project also required nearly 400 workers. Many came from the region and stayed in a camp with sleeping quarters and a dining hall on the west side of the river. A sparse camp of tents and crude structures rose on the east side of the river and served as the temporary home for Italian, Polish, Russian and Serbian immigrants recruited from Chicago.

“It was work with shovel, horses and steam,” Berndt said. “When you see some of these pictures, I don’t know how the thing was ever built. It’s primitive physics, really.”

It’s the more than 300 photographs taken by local jeweler F.S. Eberhart during the dam’s construction that really help tell the story. Photography in the early 1900s wasn’t simple and quick but Eberhart’s determination has resulted in a detailed account of the project, and some of those black and white photos are part of the museum exhibit.

The images show groups of workers posing for photos, of men eating in the dining hall and families dressed in their Sunday best visiting the construction site on weekends. One photograph shows the site before work began while others document the construction of the trestle that carried a small-gauge train used to haul rock from a quarry on the east side of the river to the construction site.

And then there are the photos of the pilings. Think of 12,000 pine telephone poles being driven into the bed and banks of the river. Concrete was poured over and around the pilings to secure the foundation on which the dam and powerhouse were built. While the technology inside the power plant has been updated and restored though the years, the wood pilings remain in place.

“They’re priceless,” Berndt said of the photos. “It’s the most extensively documented thing (for that time period) that I’ve ever seen. This is phenomenal. And the cool thing is (Eberhart) labeled them all.”

Kramer, who turns 96 on Christmas Day, is a living piece of history with a strong connection to the dam. When we talked last week, he was seated in the powerhouse break room that is positioned over the river, has large windows and provides views not across but down river. Two sets of binoculars and a spotting scope were nearby.

A 1936 graduate of Baraboo High School, Kramer was hired at the dam in 1940 to take readings and do shift work. Remarkably, some of his fellow employees helped build the dam. After a year, he left to serve in the U.S. Army as an airborne aviation engineer in the South Pacific. When his World War II service was completed in 1946, he spent a year at Bliss Electrical School in Washington, D.C., before he returned to work at the dam.

Kramer spent five years in the late 1940s and early 1950s machining replacement parts for the hydro-turbines and was among 40 people who worked at the dam. When he retired in 1980, the dam had 25 employees. Today, five work at the dam, which is now more automated.

“The number of employees has diminished over the years, but (the dam is) one of the finest resources we’ve ever had in the community,” Kramer said.

The current dam supervisor, Amanda Acton, 32, wasn’t born when Kramer retired in 1980.

“It’s 100 years old, but we take dam safety very seriously,” Acton said, of the multiple inspections done throughout the year by her employees and other agencies. “We have a lot of eyes on the place.”

Barry Adams covers regional news for the Wisconsin State Journal. Send him ideas for On Wisconsin at 608-252-6148 or by email at


Barry Adams covers regional and business news for the Wisconsin State Journal.