By Joe Darby
It’s the sinkhole that keeps on sinking. If you traverse the corner of Beauport and Royal — and many of us do, including me — you have witnessed the recurring problem of the ground giving way there. It has collapsed once more, now for the third time, and the city is about to tackle the pesky problem again.
Natchitoches City Utilities Director Matt Anderson said the problem is the poor quality of the soil in that area. He likened it to Jello or quicksand. “It’s just very, very sandy,” he explained. When men were in the sinkhole making earlier repairs they had to stand on pallets because the soil was not solid enough to keep them from sinking. “That whole area, over to the ditch by Pizza Hut, has bad soil,” he added.
Anderson said the problem of the collapsing street began several years ago when the city replaced a manhole at Beaufort and Royal. After a while the manhole collapsed, causing a large sinkhole that dropped the pavement a couple of feet, blocking off the intersection. The manhole was repaired and soil stiffening materials were used to build up the hole, with the expectation that no more troubles would occur.
But about a year later, another large sinkhole appeared. This time the collapse was nearer the median on Beauport. Anderson said city workers ran a camera through the sewer lines there, which revealed that a connection had failed at the junction of two different pipes.
That repair job was complicated by an excess of ground water which made it impossible for a quick fix-it to be carried out. Anderson said well points were installed, which resemble PVC pipes and are designed to pump out groundwater while not removing any of the underlying soil. A screen in the device is supposed to retain the soil, while the water is removed.
But apparently a hole in one of the screens caused disruption of the soil and caused the latest collapse. The current sinkhole is not nearly as large as the others, but is still a hazard to driving and is roped off. Traffic can still use the intersection.
The next method of attack on the hole will be a simple, but somewhat lengthy one, Anderson said. The hole will be filled with rocks, allowing each load time to sink and subside before another load is placed in it. “We’re not going to patch it right away,” he said, because the city wants to be sure the spot is stable before an asphalt overlay is applied.
Hopefully this simple but drawn-out procedure will work. I spent much of my life in the New Orleans area, so I’m familiar with poor soil. Street collapses are not unknown there and many houses were built without pilings and were later badly damaged by sinking and cracking foundations. A house that my first wife and I built in Algiers on the West Bank, was placed on pilings and it was a decision that saved the house from ruin. Years later, however, the soil had sunk so badly that the bottom of the foundation began to become visible and multiple loads of soil had to be brought in to fill in the gaps.
Back in the 1970s, some developer built a subdivision in Marrero also on the West Bank, in an area that had formerly been swamp. Just beneath the surface of the ground were remnants of dead, rotting trees. One couldn’t design a scenario more suited to extreme soil subsidence than that one. Anyway, the rascal built his subdivision’s houses without pilings and they were a mess. In addition, exceptionally heavy floods in May, 1979, left about four feet of water in the subdivision’s streets, because the whole place had just turned into a bowl.
I didn’t realize we also had some poor soils up here in the Ark-La-Tex, as the TV stations call it. But that’s one thing about life. You never stop learning new stuff!