By KEVIN NEVERS

It never rains but it pours, they say, and right about now the Chesterton Utility may be running out of umbrellas.

The latest problem—which Superintendent Steve Yagelski characterized as “huge”—is at least two breaches in the sanitary sewer force main from the Dickinson Road lift station, at its western terminus in the manhole at the southwest corner of the intersection of Porter Ave. and Eighth Street.

The problem was discovered at 5:30 p.m. Saturday when a Chesterton police officer observed a sinkhole form at the manhole. “It got bigger right in front of his eyes,” Town Engineer Mark O’Dell told the Chesterton Tribune today.

Yagelski was promptly contacted and on his arrival at the scene a second sinkhole to the east was found. Yagelski believes that the first sinkhole was formed when in-fill used to repair the road cut last week, following the emergency replacement of a blocked gravity main west of the manhole, began to escape into a hole at the bottom of the manhole, possibly formed when a vertical ductile iron T-joint from the Dickinson Road force main snapped. The second sinkhole is “presumably” the result of more in-fill escaping into another breach in the force main, Yagelski said.

In any case, those two breaches had not yet been exposed this morning by excavating contractor R.V. Sutton Inc. What has been exposed, however, is frightening: a ductile iron force main so corroded at its terminus that it will be impossible to yoke a PVC replacement to it. At this point Yagelski simply doesn’t know how far to the east the integrity of the force main has been compromised. As far east as Fifth Street? “I hope not,” he said.

It could be, Yagelski added, that the tendency of the hydrogen sulfide gas produced by sewage to collect at the very end of the force main is responsible for the corrosion of the ductile iron and that the pipe is in much better shape as it runs east. But Yagelski won’t know until the pipe is exposed.

The force main itself, installed in 1993, is 16 inches in diameter and is located between 11 and 15 feet below street level on the north side of Porter Ave. Near its terminus it veers to the southwest to run into the manhole.

O’Dell did say that it would appear this latest problem is entirely unconnected to the blockage of a concrete gravity main which runs from the west into the manhole. That blockage forced the emergency replacement of 175 feet of the main in an operation which was completed on June 14.

“It’s a freaky coincidence,” O’Dell said. “It’s just a timing thing. It’s unbelievable.”

Complicating the initial investigation, Yagelski noted, was a failing valve on a water main located at the intersection, which was flooding the excavation until Indiana-American Water Company dispatched a crew to repair it. Yagelski does not believe that the leak caused or contributed to either of the sinkholes.

Meanwhile, since 12:45 a.m. Sunday a rotation of six vacuum trucks—two from the Utility, two from Eagle Services, and two from H20 Industrial Services—has been working around the clock at the Dickinson Road lift station, which had to be deactivated to allow crews to work. So far no backups have been reported in basements.

The manhole in question is a major underground nexus: three gravity mains converge there, one from the east, flowing from Fifth Street; one from the south, flowing from South Park Acres; and the blocked one which had to be replaced, flowing from the west. Two force mains also converge there: the one from the Dickinson Road lift station, the second from the Chesterton High School lift station. All three gravity mains and both force mains empty into the huge and very deep 42-inch gravity main which runs north on Eighth Street to the wastewater treatment plant.

Yagelski fears that this latest emergency will prove far costlier to resolve than the previous one, which was costly enough at more than $44,000. At last week’s meeting of the Utility Service Board, both Yagelski and O’Dell voiced the opinion too that the 389 feet of the gravity main which were not replaced following the discovery of the blockage should be replaced sometime this year. Whether that project will be pursued in light of the failure of the Dickinson Road force main remains to be seen.

Posted 6/23/2008