Smoke testing begins effort to combat flooding in Cedar Rapids’ southeast quadrant

CEDAR RAPIDS - Smoke billowing up from homes, yards and manhole covers in the southeast quadrant of Cedar Rapids on Monday is the beginning of an effort to identify defects in an overwhelmed and in places broken sanitary sewer system, which has caused flooded basements during heavy rain events, including along Grande Avenue SE and Blake Boulevard SE.

A crew from Central Iowa Televising of McCallsburg on Monday pumped liquid smoke into a manhole along Ryecroft Street SE and walked between homes to monitor where the smoke emerged. In most cases the smoke puffed from sewer stacks sticking up from roofs, which is ideal.

'What is normal is smoke coming out of sewer stacks,” said Sandy Pumphrey, stormwater engineer for the city of Cedar Rapids. 'It shouldn't be coming out of gutters or the ground or stormwater intakes.”

Cracked pipes allow stormwater to infiltrate the sanitary sewer system, which carries away wastewater for treatment. Significant added water overwhelms the system both straining capacity at the water treatment plant and backing up in home basements.

Pumphrey said the smoke is odorless and safe. If smoke gets into a person's home it could be a sign of a plumbing problem, and people can clear the smoke by opening a window, he said.

The smoke testing, which is expected to last through the week, is being coupled with door-to-door inspections this month where officials are looking for cross-connections or when home drainage, such as sump pumps, drain tiles or gutters are tied directly into the sanitary sewer system. Cross connections are not allowed in Cedar Rapids and are another factor in overwhelming the sanitary sewer system.

Teams of two - a city staffer and an employee from HDR Engineering, of Cedar Rapids, will be seeking permission to enter homes to visually confirm if cross connections exist. The city will cover the cost of disconnecting in the pilot area, which includes about 600 homes.

The total cost of the pilot project, which includes smoke testing, the inspections and disconnects is not expected to exceed $400,000, Pumphrey said.

'We are trying to look for anyone with cross connections or areas there might be gaping holes in the pipes,” he said.

Eric Johnson, operations manager for Central Iowa Televising, was part of the crew surveying where smoke emerged on Monday. He said workers noticed a large void in the grounds by the Brucemore Mansion, cracked concrete with smoke pouring through in one place, and smoke coming out of numerous manhole covers, which is only a problem if the manhole is sunk below grade and thus susceptible to water pooling and draining into it.

As expected, the Ryecroft area, which is just south of Cottage Grove Avenue SE, was in good shape because it has newer homes built in the 1980s.

As testing continues in older neighborhoods, such as Wellington Heights, the defects are expected to increase, Johnson said. In this case, smoke could surface in unexpected places, such as the middle of the yard, storm intakes or foundation drains, which could be a sign of cracked pipes and cross-connections.

'There's a lot more cross connections in older homes,” Johnson said. 'In the 1920s, the solution to pollution was dilution. Now every ounce of water has to be treated.”

The data of where smoke is emerging will be collected for possible future work on upgrading the sanitary sewer system.

Dave Haugen, project manager with HDR, said for now, the disconnections are fairly simple and should have a positive impact on issues in the area.

'It's a relatively low-cost fix,” he said.

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