LOUISVILLE, Ky. — The Louisville Zoo and Mega Cavern reopened Friday, March 15, more than a week after staff originally discovered a subsidence on zoo property.

Vector Engineers, Inc. reported the massive hole in the ground found near the Louisville Zoo on March 6 is a ‘subsidence,’ not a sinkhole, caused by too much water weakening the Louisville Limestone.

A report on Friday said engineers found a pipe that “focused the water flow to a shallow ditch at the west end of the subsided area,” and determined it was “over-saturation of the overburden soils, and from saturation of the joint(s)” that ultimately resulted in those ‘joints’ losing strength and subsiding into the ground. 

The report also said “a sinkhole is typically due to soil raveling into a void or conduit within a limestone or dolomite bedrock over a period of time. Bedrock collapse sinkholes are rare in Kentucky.”

While the hole in the ground is 60 yards wide and 90 yards long, zoo officials said the subsidence affected less than one percent of their property and will not impact the rest of the area.

RELATED: Louisville Zoo, Mega Cavern to remain closed after sinkhole found

Officials continue to call this an isolated incident that happened in an ‘unoccupied area’ which is why the Louisville Zoo and Mega Cavern re-opened. Several people went to zoo on its first day back, saying how excited they were to see the animals.

“She's been talking about the hole being fixed all week, so she's excited,” zoo-goer Hannah James said about her daughter, Lainey. 

The zoo stayed closed for nine days while engineers thoroughly inspected the area around the subsidence before determining it safe. 

“You don't want to put anyone in danger, so you want to make sure everything is right and ready to go,” Quincy Johnson, a parent at the zoo Friday, said.

RELATED: Geology Professor: Sinkhole at zoo likely caused by wet winter

In this situation, engineers had to also explore below ground where the Mega Cavern attractions are. Tours started back up Friday, as well. 

“We have people flying in from out of town to go zipping today, so you better believe that we love this time of year,” Jim Lowry, one of the Mega Cavern owners, said.

Lowry said March is actually one of the Mega Cavern's busiest months, so closing for nine days hurt. 

“It has had a dramatic impact on our sales for this month, no doubt about it,” he said. 

Lowry said the Mega Cavern could have opened last Saturday, but as a courtesy to the zoo, they waited to announce on the same day.

Crews have put a barrier 40 feet from the perimeter of the subsidence. The barrier will stay in place until a permanent solution is implemented, officials said.

Parents said they were pleased both the zoo and Mega Cavern did not rush to reopen, with safety of its guests in mind. 

“We would not want a cave-in in the middle of people being here, so I'm glad they took the time they needed to make sure it was all good.”

The Louisville Zoo announced it would extend the winter discount for a week. Adults will be charged $9.95, and children charged $6.95.