Smoke testing uncovers many public sewer defects

This summer?s drought has been the subject of many complaints, but not from Mike Starkey of McClure Engineering Company, who said it has aided him in smoke testing sewer lines on the east side of Fairfield.

Starkey was surprised at the extent of defects the crew found in public sewer lines. Testing uncovered 327 defects in the public sewer system through curb inlets, area drains, line and manhole defects, drainage crossings, water valves and direct connections to the stormwater system.

?We have found a high number of direct connections,? said Starkey. ?It?s a higher than average number.?

McClure began testing mid-August with assistance from French-Reneker-Associates, injecting vapor into sewer lines with high-capacity blowers to find connections where stormwater is entering the system. Starkey said rain often fills cracks or holes in the system, trapping smoke where defects exist. He said the dry conditions have contributed to ?a very productive evaluation.?

The study exposed 69 curb inlets, which he said are especially significant, allowing large amounts of stormwater into the sewer system.

?That is not preferred,? he said. ?You want to keep them separate.?

Defects in private lines were relatively low in comparison, with a total of 178 issues found in service laterals, plumbing defects, downspouts, drains, window wells and uncapped cleanouts.

?It wasn?t as many as we expected,? said Starkey, ?They are not contributing [to inflow] nearly as much as the public connections.?

Starkey said the city will decide how to work with residents to ensure they fix issues with private lines.

?There?s lots of ways to tackle it,? he said.

The last time the city conducted smoke testing was during the summer of 2007 in response to impending fines from the Iowa Department of Natural Resources for sanitary sewer overflows. The city hired French-Reneker to test a section of town north of Central Park.

The city has long been aware of serious issues of inflow and infiltration of water into the aging sewer system leading to sanitary sewer overflows. The sewer overflows into streets and waterways during heavy rain in roughly 20 known locations in the city.

Smoke testing is one piece of a larger inflow study

the city hired McClure to complete to assess the level of deterioration of the wastewater system.

City administrator Kevin Flanagan said the city is tackling sewer repair in two phases beginning with the east side of town during the first three to five years, and completing the west side second with a similar timeline. Flanagan said the east side of Fairfield has the most pressing needs, containing the wastewater plant itself along with oldest sections of the city?s sewer infrastructure, with some areas roughly 100 years old.

Flanagan stressed the importance of planning at the Fairfield Area Chamber of Commerce?s Business Before Breakfast Monday morning, where he shared an overview of city projects with area business representatives.

?Even though it kills you to wait, you have got to know what you?re doing before you do it,? he said.

Flanagan said once the city begins phase one to repair the sewer system, residents will notice an increase in their sewer utility to pay for the project.

?A few months prior to each project, we?ll start accruing funds,? he said. ?It will all be paid through fee rates.?

He said increases will be phased in during the next 20 years and has been estimated to cost up to $30 million.

?It won?t be $20 every five days,? he said. ?It will be more like 3 percent here, 2 percent there.?

Flanagan said Fairfield is similar to cities throughout the United States that have kept rates low at the expense of maintaining the sewer system. He also said Fairfield is not unusual to other cities in receiving notices from the DNR, mandating the city correct the issues or face fines.

?The DNR in states all over the nation are going out and giving cities papers they don?t want to be getting,? he said.

Flanagan said the results of smoke testing are just one sign Fairfield has let the sewer go too long without repair.

?Through smoke testing we?ve been able to identify inordinate amount of bad connections,? he said. ?We?ve subsidized complacency for 30 to 40 years.?