A few feet from Macon’s levee, a large sinkhole has gaped for several weeks in Central City Park at the spot where the river trail begins.
Officials with the city and Macon Water Authority suspect the sinkhole is related to one of the large sewer lines in the area, and the authority is hiring a contractor to investigate.
“This is an unknown for us, and it will have to be kind of a trial and error approach,” said Ray Shell, the authority’s assistant executive director. “It is a real concern for the levee and for the safety of the park.”
The hole has swallowed pavement in one of the park roads, and the parking area near it has been blocked off. Yellow hazard tape has been stretched around it, although it’s possible to stand on the lip of the hole while outside the tape.
The sidewalk of the Ocmulgee Heritage trail dead-ends directly into the hole, which is about 20 feet in diameter and about 10 feet deep.
“We’ve been trying to get them to do something pretty quick, because we have a lot of activities planned in that park, and we want it to be safe,” said Larry Fortson, assistant director of the Macon-Bibb County Parks and Recreation Department.
But because of the difficulty in tracing the cause of the sinkhole, repairs are still probably weeks away. A “Kid’s Day” was held in the park last Saturday, and this weekend the park hosts Macon’s Pan-African Festival.
Fortson said his department has heard no complaints or concerns from park users about the sinkhole.
The hole could have implications for the integrity of Macon’s levee, which is supposed to keep the river from flooding downtown Macon. Years ago there were “boils” behind the levee where water was infiltrating the earthen wall, but those were fixed and weren’t in the same area, said Bill Causey, director of Macon’s engineering department.
The U.S. Army Corps of Engineers threatened for several years to decertify Macon’s levee — potentially stripping flood insurance protection from many properties — unless repairs and maintenance were done. The water authority completed the last of these in the fall when it removed trees from a southern portion of the levee.
The corps has not yet reinspected the levee since that work was done, although it plans its annual inspection within the next few weeks, said Billy Birdwell, public affairs director for the Savannah corps district.
The sinkhole appeared during the last heavy rain, when the Ocmulgee River flooded almost two weeks ago.
Immediately afterward, the water authority used a vacuum pump to try to remove the water from the hole, Shell said. But water levels did not drop until the river dropped, implying that somehow river water was getting through.
Shell said there is some evidence of sewage in the hole, which is next to a 54-inch sewer line that brings sewage beneath the river with the help of a pump at Main Street.
That pipe may be allowing in river water and soil, Shell said.
“There’s a large volume of soil missing,” he said. “It has to have gone somewhere.”
Causey said the problem may be an old sewer line that runs along the levee and was abandoned in 1978. It should have been capped at both ends when it was replaced. But if it wasn’t or if it has broken, water could be flowing through it.
That was a problem at the place where the river breached the levee during Tropical Storm Alberto in 1994, Causey said. The contractor hired to fix the breach had to remove a section of the old pipe because it kept channeling water into the levee.
The authority is awaiting a contractor’s estimate for examining the inside of its working sewer line with closed-circuit cameras. The line is too large for the authority’s equipment to handle, Shell said.
The pipe carries such heavy flow that the video surveillance of the interior will have to be done in the middle of the night, Shell said. The authority will have to turn off the nearest pump station while the contractor creates a temporary bypass pipe to send sewage around the section of sewer main.
Causey said the city has no significant concerns about the integrity of the levee right now.
“If we had a lot of rain coming, then I’d be concerned and would ask for (the authority) to declare it an emergency and get it done,” he said.
To contact writer S. Heather Duncan, call 744-4225.