GRANITE FALLS -- Xcel Energy intends in 2012 to remove an aged dam that no longer serves any purpose for the company, but upstream water users including a large ethanol plant are voicing concerns about how it will affect them.
Xcel Energy decided this summer it will move forward with plans to remove the Minnesota Falls dam on the Minnesota River south of Granite Falls rather than repair it or replace it with man-made rapids, officials with the company and Barr Engineering told about 50 residents Wednesday night in Granite Falls.
Constructed in 1905, the concrete masonry structure is at the age where major repairs are needed, according to Jon Ausdemore, engineer with Barr Engineering.
It will cost an estimated $2.2 million to $2.9 million to remove the dam, which is 600 feet wide and 12 to 14 feet high.
That removal cost compares to estimates of $5.2 million to $6.9 million to repair and replace it, and $5.5 million to $7 million to create a rock rapids in its place that would keep the current river elevation, according to information from Tom MacDonald, engineer with Barr Engineering.
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The dam was built for one of the state's first hydroelectric facilities, and the reservoir it created provided cooling water for Northern State Power's Minnesota Valley coal-fired plant. Hydroelectric generation ended there in 1961. The coal plant has not operated since 2004.
Xcel Energy is likely to dismantle the 1930s-vintage coal plant within the next 10 years, according to Tim Brown, Xcel manager for the facility and the Angus Anson plant.
The dam is no longer needed by Xcel, but the company retains liability for as long as either it or a man-made rapids would exist, Brown and other company officials explained.
Xcel is open to transferring ownership of the dam, but cautioned that any new owner would also acquire the costs for repairing the dam and the long-term liability. The Minnesota Department of Natural Resources has been urging Xcel to either repair or remove the dam due to safety concerns, according to MacDonald. Were the dam to fail, there is the possibility of loss of life, he explained.
The Granite Falls Energy ethanol plant has its water intake directly above the dam, and would be the most affected by its removal, according to MacDonald. He said the removal of the dam would lower the water level at the site from 7 to 14.5 feet, depending on river flows. During some low-flow periods, the ethanol company's intake could be left high and dry once the dam is removed.
MacDonald said the intake could be modified to accommodate the changed river level, and called the situation "solve-able.''
Tracey Olson, chief executive officer with Granite Falls Energy, said the company is concerned about the costs for modifying the intake. He and others also expressed concerns about obtaining permits and assurances that the water supply will not be disrupted. The Minnesota DNR had urged the ethanol company to install its intake on the Minnesota River, rather than rely on groundwater or Hawk Creek as its primary water source.
The lowered river level will increase the cost for pumping water to irrigate the nine-hole Granite Run Golf Course about one mile upstream, according to Dave Reimer, its owner. "Make me whole,'' he told Xcel officials.
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The city of Granite Falls is also concerned about how a lowered river elevation might affect the aesthetics of the river upstream to the city, according to Dick Wambeke, who represents the city on the Yellow Medicine County Board of Commissioners.
Granite Falls Mayor Dave Smiglewski also expressed concerns that a lowered river elevation might cause icing problems with the city's wastewater discharge outlet located about two miles upstream of the dam.
If the dam is removed, the drop in elevation during normal flows would range from a 7-foot drop at the dam site to only 6 inches in the downtown area of Granite Falls, according to the project engineers.
The river channel upstream of the removed dam would narrow, but not greatly, according to MacDonald. The channel would be similar in width as it is currently below the dam. The dam's removal would leave a 4- to 5-foot natural waterfall over bedrock at the site, he said.
Xcel representatives said its legal staff is looking into whether the company has obligations to upstream water users affected by the dam's removal.
The city of Granite Falls had explored buying the dam and installing new hydroelectric generation equipment at it. The need to maintain a minimum flow of water over its spillway to protect the downstream fishery made the project economically unfeasible, according to Mayor Smiglewski.
