The Wisconsin Department of Natural Resources has ordered a drawdown of the Little Hope Millpond in Dayton.
According to the DNR’s order, dated Sept. 4, the drawdown is not to exceed six inches per day and the water is to be down to the lowest sill level of the dam’s main gates by Oct. 1.
DNR staff conducted an assessment of the concrete dam on Aug. 28 and found seepage along the left abutment.
“The embankment was deteriorated and was previously patched with concrete and asphalt,” the DNR noted in its report. “The dam, in its present condition, is not sufficiently strong and is unsafe and dangerous to life, health and property.”
The millpond, located on the Crystal River near the Red Mill, must remain drained until the dam is replaced or abandoned.
Waupaca County currently owns the dam and must decide whether to replace it or remove it by Dec. 1, 2013.
Dayton residents and town officials spoke to the Waupaca County Parks and Recreation Committee, which oversees the dam, at a meeting Monday, Sept. 10, at the courthouse.
“There is no danger of the dam washing out,” according to Dayton Town Chairman Chris Klein, who noted that seepage has been a problem at the dam for many years.
Klein said the town hopes to establish a lake district around the millpond.
Under state law, lake districts are a special purpose unit of government that have authority to set regulations to protect a lake. All property owners on the lake or who benefit from it share in the costs and vote at the district’s annual meetings.
“To drain the pond and eliminate the dam is not a solution that works for the people who live in the area,” Klein said, adding that the dam and the millpond were historic landmarks.
Rose Dorow, who lives near the dam, also noted how both local families and tourists visited the millpond, the Red Mill and the small park located near the dam.
“In the summer, I see children fishing there and lots of people visiting the park.” Dorow said.
Jane Haasch, a member of Dayton’s Planning Commission, pointed to the dam’s economic value. She said losing the dam would affect local property values as well as tourism.
Rick Nelson, who has owned a home on the Little Hope Mill Pond since 1983, said he purchased that property because it was located on open water. County Supervisor Bob Ellis said repairing or replacing the dam would cost a fraction of what would be lost in property values in the area.
“I think the solution can be something less dramatic that eliminating the dam,” according to Bob Van Epps, a member of Weyauwega Lake Restoration and a Dayton resident.
Van Epps pointed to a number of potential consequences if the dam is removed.
He said the millpond affects the area’s water table, which in turn will affect the two plumes seeping out of the abandoned landfill. He said eliminating the millpond could make 15 years of data tracking the landfill seepage irrelevant.
“The towns of Dayton, Farmington and Lind have more money invested in monitoring the landfill than what it would cost to repair or replace the dam, Klein said.
County Parks and Recreation Director Roger Holman said problems with the Little Hope dam first came to light nearly two years ago after he inspected the dam and observed concrete breaking away and erosion upstream.
“We needed a permit from the DNR to work on the dam and we needed an engineering study,” Holman said.
Engineers with Ayres and Associates surveyed the dam in January 2011 and presented their findings to the Parks and Recreation Committee in September 2011.
The study concluded that the dam needed to be replaced or repaired.
“If a rapid catastrophic failure of the dam were to occur, it would result in a rapid release from the lake with a wall of water impacting County Trunk Highway K downstream of the structure. This could cause County K to wash out and result in a significant risk to the general public, as well as the cost to the existing structure,” the report said.
Ayres Associates provided cost estimates for four options, ranging from removing the dam for about $210,000 to replacing it with an armored overflow section and new stop log bays for a cost of $425,000.
Removing the dam would allow the stream to revert to its natural condition. However, the Ayres study indicated that a 600-foot long, 30-foot wide and 3-foot deep channel would have to be dredged upstream of the dam site.
Another option would be to replace the stop log structure with two split leaf gates for a cost of $405,000. A third option is to replace the current dam with a labyrinth spillway, which would also cost about $405,000.
Holman said that after receiving the drawdown order, he contacted the DNR and asked if it would reconsider the order to replace or abandon the dam if he could provide a certified engineering study that repairing it would be sufficient.
Holman said he cannot predict whether the dam “will fail tomorrow or last another 20 years. But we know there are problems with the dam.”
County Supervisor Gene Sorensen, who sits on the Parks and Rec Committee, said the Dayton residents who spoke at the meeting brought up issues that he believed the DNR should consider.
“I want to hear what the DNR thinks of these comments,” Sorensen said, adding that the DNR should be fully informed before making a final decision. The committee then voted to delay draining the millpond and meet with the DNR regarding the dam.
The county has less than 30 days to appeal the DNR’s decision.
A public meeting on the millpond, the dam and the formation of a lake district will be held at 1 p.m. Sunday, Sept. 16, at the Dayton Town Hall.