Chesterton Tribune



Utility eyes preemptive slip-lining of North Calumet sewer

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After the failure in June of a 321-foot section of 12-inch concrete sewer main below North Calumet Road, the Chesterton Utility is having serious thoughts about the condition of an additional 730 feet of pipe.

As Superintendent Dave Ryan told the Utility Service Board at its meeting Monday night, the other three sections of pipe--514 feet on Wabash Ave., 181 feet south of the failed section on North Calumet Road, and 35 feet north of it--are just as old as the section which was recently replaced: 75 years or more.

And there’s no good reason to suppose that the pipe still in the ground is in any better condition, eaten away as it’s been over the years by sewer gas, hydrogen sulfide in particular.

For that reason Ryan expressed an interest in exploring the feasibility of slip-lining the remaining sections of concrete pipe. From a cost-benefit perspective it would probably be the smart thing to do, he said, given the fact that it cost just under $80,000 to replace the failed section, at $242 per foot, but could cost as little as $56,000, or $75 per foot, to slip-line all 730 feet of the remaining sections.

Slip-lining would also be a minimally invasive solution to the problem, Ryan added, requiring no excavation and having a likely service lifetime of a lifetime.

Still, Ryan warned the Service Board, there’s no guarantee, that the 730 feet of pipe are in good enough condition to take a slip-line. That determination would have to be made by the contractor.

Members voted unanimously to authorize Ryan to pursue the slip-lining. They also expressed their appreciation for the expeditiousness of the repair on North Calumet Road. “Your staff did a great job,” Member Scot McCord said at the end of the meeting. “I don’t think any businesses were hurt. And then to get it turned around as fast as you did.”

Member Jim Raffin concurred. “You guys minimized the disruption,” he said.

West Morgan Ave.

In other business, Ryan suggested that there may be call to slip-line another section of sewer main, this one the 30-inch monster 14 feet under West Morgan Ave. between South 15th Street and South 14th Street.

At issue: a sink hole whose cause hasn’t been conclusively identified but is probably a breach at the top of the 30-incher.

Since the sink hole first appeared, late this spring, the Utility has filled it twice with gravel, the second time after the hole re-appeared to a depth of two to three feet. That gravel could well be disappearing through a rupture in the pipe, Ryan said.

A crew did do a bit of excavation and while not deep enough to expose the 30-inch main it did indicate that there are no other utility pipes in the area which could be the cause of the sink hole, Ryan remarked.

In any case, Ryan told the Service Board that he will investigate the cost of slip-lining this section of pipe and report back.

July in Review

Chesterton used 47.66 percent of its 3,668,000 gallon per day (gpd) allotment of the wastewater treatment plant; Porter, 47.84 percent of its 851,000 gpd allotment; the Indian Boundary Conservancy District, 50.43 percent of its 81,000 gpd allotment; and the plant as a whole, 47.74 percent of its capacity.

There were no bypasses in July, which saw a total of 5.84 inches of rain, the wettest month of the year so far.

In July the Utility ran a surplus of $302,645.79 and in the year-to-date is running a surplus of $634,211.52.



Posted 8/22/2017




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