Seam at bottom of National Quarry cause of water loss

A report published by the Great Lakes Geological Survey - Eastern Division warns that the National Quarry, bordering Jefferson Street and the Norfolk & Western Railroad, could be empty by 2017.

The cause of the water loss is due to seams discovered in the quarry regolith, which is directly above the bedrock.

Last fall the water level in the quarry was four feet lower than at the same time in 2013. This prompted a study by the geological survey team. The findings show that a seam measuring 20 meters long and up to 2 centimeters at the widest point is in the north end and in the bottom trench of the National.

Described like a plug in a bathtub, water is seeping through the regolith area into the bedrock. An ultrasound of the quarry revealed the seam narrows as it deepens, but that it could be up to 10,000 meters (2 miles) deep.

This geological issue, called “bedrock spoil” occurs when carbonated limestone, common in the Bluffton area, buckles due to the weight of random air pockets produced in the jet stream.

This condition has caused several large bodies of water across the globe to shrink. The most notable is the Caspian Sea in southern Russia. Bluffton’s limestone is identical to limestone found in Caspian Sea bedrock.

An information meeting on the report takes place at 8 p.m., Wednesday, April 1, in yet-to-be-named location.

Stories Posted This Week