NATCHEZ — The failure of an old cistern is the likely cause of the formation of a large sinkhole on private property in downtown Natchez this week.

The rectangular sinkhole, which is approximately 10- to 12 feet wide and 12 to 15 feet deep, formed in the courtyard area behind 619 and 621 Franklin St. late Sunday night or early Monday morning, property owner Linda Wilbourn said.

While the sinkhole pulled at a wooden walkway in the area, Wilbourn said it did not threaten the structure of the buildings.

“We don’t think there is any danger at this point,” she said. “We think we have stabilized it. I am glad no one was hurt.”

The cistern over which the sinkhole formed was likely used for the storage of water used to fight fires, Wilbourn said.

“I had no idea there was a cistern out there,” she said. “I have been told that with these old buildings there were usually two cisterns, one for drinking water and one for fires. They would stick the hose down in the great big pipe and the fire people would pump it out — you can see the city’s old pipes here.

“We don’t know whether it was properly filled in or just settled over the 100 years since then.”

The hole will be filled with “lots and lots” of sand, Wilbourn said.