A tunnel has collapsed underneath a parking lot on Main Street in Eureka Springs.
John Cross, who owns the parking lot, said the hole was the size of a washtub late Friday.
By Thursday, it was about 66-by-40 feet and 25 to 30 feet deep.
But that was after Cross hired a man with a backhoe to remove the asphalt "crust" covering a much-larger-than-apparent sinkhole.
Cross said "gawkers" were stepping over the yellow police tape and walking to the edge of the hole to peer down inside.
"I know they're curious, but we have to protect them from themselves," said Cross. "One of our concerns is someone was going to get over there on the crust of this thing, and it was just going to give way.
"The asphalt was just a crust going over this hole, like the crust of a pie."
Sinkholes are fairly common along Main Street in Eureka Springs. A century ago, several buildings were constructed along the southeast side of Main Street straddling the eastern branch of Leatherwood Creek, which flows for about 1,500 feet through a tunnel underneath buildings and parking lots.
Cross calls the creek a stormwater sewer.
"It's a storm sewer collapse," he said. "Our storm sewer in Eureka Springs is creaky. Some of it is good, but most of it is not."
Dwayne Allen, the Eureka Springs public works director, calls it the North Main Stormwater Aqueduct.
It runs underneath several buildings in the area, including The Auditorium and the Carroll County Courthouse in Eureka Springs.
At some point, dirt was hauled in to fill the gulch and allow construction above ground while the creek flowed freely underneath. But more than dirt was dumped in the gulch.
Cross said he has found wagon wheels and remnants of automobiles in the tunnels. As some of the organic material in the fill decays, it leaves tunnels underground, he said.
In the past decade, there have been five tunnel excavation and repair projects along Main Street, said Allen.
"Two years ago, we had a Chevrolet Suburbia drop a few feet into a large hole on Mountain Street, due to the failure of a section of 36-inch clay tile storm drain from the 1930s," said Allen. "Please note Eureka Springs is still safe to visit, and we have not lost any lives or vehicles."
Allen said the city is to begin work Monday on a tunnel repair on Flint Street, which intersects with Douglas and Main streets. The estimate for that repair is $205,605, but the city has received a grant from the Arkansas Economic Development Commission that will pay the vast majority of that cost.
Allen said something like a reinforced concrete box needs to be installed in the hole under Cross' parking lot, then pavement applied on top of that.
Cross said he'll pay the initial cost to repair the tunnel underneath his parking lot, but then he's going to look to the city for some financial reimbursement. Cross said it's a safety hazard now, and debris from the collapse will clog the creek, which could cause flooding in some of the historic buildings along Main Street if there's a heavy rain in the near future.
Cross said it's the city's storm sewer that runs underneath the buildings.
"All the storm sewers are the city's property no matter where you go," he said. "Any engineer would say it's a city problem. Why would a landowner be responsible for all the water coming off a mountain?"
Mayor Robert "Butch" Berry said tunnels on private property are the responsibility of the landowners.
"This wasn't built by the city," he said of the tunnel. "This was built by private individuals."
Berry said there probably wasn't any compaction of the fill material when they put the parking lot in, and it's settling now.
"The city didn't build a parking lot over that creek," he said.
Two years ago, the city approached property owners to see if they wanted to form a property owners association and tax themselves and go in and repair the creek tunnel. But nobody wanted to do that, said Berry.
Cross has owned the parking lot along Main Street since 1977. It's between Chandler Mall building and Basin Spring Bath House. Cross has closed the parking lot for now, while the excavation is underway. He said the lot has spaces for 27 vehicles.
Cross is chairman of the board of Cornerstone Bank and the grandson of Claude A. Fuller, who was a congressman in the 1930s.