The city of Eureka Springs plans to fix the the century-old dam at Black Bass Lake.
It's been leaking for years.
"I've been trying to find money for this for 15 or 20 years," said Mayor Robert "Butch" Berry, who has been mayor for eight years and served on the City Council for 10 years before that.
Finally, the city has the money. Or most of it.
Berry said the city got a $300,000 Federal Emergency Management Agency grant and has pandemic-related stimulus money that can be used for the repair.
He said the repair will cost at least $600,000.
"We've got it out for bids right now so we'll find out what the cost is and we'll go from there," he said.
Berry said the city will start the work even if it doesn't have all the money at that point. He said it will probably take six to nine months to complete.
"The earthen and cut-stone dam dates to 1894 and is one of the oldest still standing in the Ozarks," according to the city's Parks and Recreation Department.
Berry said some of those stones have been coming loose and tumbling to the ground.
If the 28-foot-tall, 228-foot-long dam failed, the rush of water from the lake could destroy a pump station for the Carroll-Boone Water District that's located about 200 feet away.
Berry said that would mean no water for the western side of Eureka Springs, including the City Hospital and the Crescent Hotel. It would also mean no fire protection or drinking water for people on that side of the town, he said.
"It's a life safety issue for the citizens of Eureka Springs," said Berry.
He said it's not a matter of if the dam fails, but when the dam fails.
"The dam as it sits there right now is stable," said Bill Hathaway of Holiday Island, the engineer for the dam repair project. "It's not in any danger of collapsing that we can tell."
The dam consists of a 20-foot-tall section built in 1894 and an 8-foot-tall addition built on top in 1915. Originally, water was allowed to flow over the dam, but the addition impounded more water in Black Bass Lake, which was used as the city's water supply until about 1960. The lake is now the centerpiece of a recreational area with trails and fishing.
The leaking is occurring in the top section of the dam, said Hathaway.
"The dam has deteriorated radically over the last five years," he said. "Most of the surface material has eroded and is laying at the bottom of the dam, exposing the core of the dam."
Hathaway said the core of the dam is a mixture including soil and cement with a mortar over its face.
He said the danger is that flooding could cause water to overtop the dam and erode the core material or earth on the other side and cause the dam to fail.
"If the thing overtops, you have a tremendous amount of water going over," he said. "It's likely to overtop if you have a major flood condition."
There's a spillway on the west side of the dam.
"The problem is they don't have enough spillway," said Hathaway.
For the dam repair project, Hathaway said he's proposing a stairstep structure to the dam's surface. It will be made with stone retaining walls, which average about 4 feet long, 14 to 16 inches tall and 2 feet in depth.
That way, if the dam is overtopped, the energy of water coming down the north side will be dissipated by the steps, he said.
"The original dam was a stairstep design," said Hathaway. "Whoever came back with the stones on the back covered up the stairstep and made a slope of stones."
Berry said trails near the dam are still open, but people aren't allowed to walk over the catwalk on top of the dam.