A major storm sewer separation project that was to have been completed this summer in Riverside’s First Division won’t get started until spring 2017 at the earliest, and the price tag for the improvements is now projected to be at least double original estimates.
That’s because what the village’s engineering firm expected to find underground didn’t match what actually exists.
Instead, the firm encountered puzzling, unexpected connections between what was presumed to be storm sewers and sanitary sewer service lines coming from several homes.
It’s unclear just how and when those connections were made, but the village’s engineering firm confirmed finding 13 homes whose sanitary service lines connected directly to the storm sewer, most of them along Scottswood Road.
On Friday, Aug. 19, Village Engineer Orion Galey of Christopher B. Burke Engineering Ltd. was out in the First Division along with personnel from RJN Group, an engineering firm that specializes in sanitary sewer engineering. Burke hired RJN Group to do “smoke testing” to determine exactly which homes’ sanitary service lines were connected to the storm sewer.
Workers plugged sections of the storm sewer and then placed smoke bombs into a fan unit, filling the sewer with white smoke that eventually found its way into the sanitary systems of homes connected to it.
In most cases, the tell-tale smoke could be seen exiting the homes through the sanitary vents atop their roofs. In a handful of cases, the smoke also filled parts of homes, setting off smoke alarms. One home on Scottswood Road filled with so much smoke – it was seen billowing out of the home’s downspouts as well – that the owner called the fire department and angrily demanded to know what was going on.
“I thought my house was on fire,” the homeowner said.
In the coming weeks, the 13 homes will be dye-tested to absolutely confirm the cross connection to the storm sewer system. Then it will be up to the village’s engineering firm to redesign the First Division storm sewer separation project.
Back in February, when the engineering firm first uncovered the discrepancies between existing sewer maps and reality, they got the go-ahead from the village board to spend another $142,650 on engineering and $35,000 to televise the sewer lines.
Two years earlier, the engineering firm, Christopher B. Burke Engineering Ltd., delivered a sewer improvement plan to the village board.
The sewer maps used for that plan were completed through the GIS Consortium, of which Riverside is a member. GIS, or Geographic Information System, provides pinpoint data for everything from the village’s tree inventory to geographic contour mapping.
According to Galey, the sewer map was based on the decades of information supposedly contained in paper sewer atlases created originally in 1939.
But changes in that information apparently weren’t always updated on paper throughout the years.
The upshot was that the First Division storm sewer separation project that was originally estimated to cost $2.4 million has now been revised upward to $5.75 million, though it’s difficult to say right now exactly what the ultimate solution is going to be.
Galey said one potential solution would involve turning what is now the “storm” sewer in the First Division into its new sanitary line, since so many residential connections to it already exist.
That would require building an entirely new storm sewer line and abandoning the existing sanitary sewer, which dates from the late 19th century.
During the next three or four months, Burke Engineering will be determining the best route to take and will complete new designs, complete with cost estimates, that the village board can consider as part of its 2017 capital budget.
“We should have a direction for the board by the end of the year,” Galey said.
Should the village choose to move ahead at that time, Burke would seek bids in early 2017 with construction targeted for the spring.
Asked whether he expects to run into the same kind of sewer map discrepancies in other parts of the village, which the 2014 sewer improvement plan also addressed, Galey said he wasn’t sure.
“It’s tough to say if it’s the same elsewhere,” said Galey, who noted the First Division contained the village’s oldest sewers. “I’m hoping this is the worst they’ve got.”