Oregon council will consider awarding a contract on Monday to a firm to conduct smoke testing in the sanitary sewer system to find the causes of flooding that have occurred in parts of the city following heavy rainfall in the last few years.
“Over the past few years, we’ve had issues with wet weather, and storm water getting into the sanitary sewer system,” said Public Service Director Paul Roman. “One of the tools to find out where the storm water sources come from is smoke testing. It is just a matter of blowing a lot of smoke into the sanitary, and walking into a neighborhood, looking to see where exactly the smoke comes out.”
The city has been vigorously addressing flooding problems after heavy rain, including the installation of temporary flow meters at five locations in the sanitary sewer system to reduce or eliminate excessive storm water from getting into the wastewater collection system. Flow monitoring, video detection and smoke testing help identify Inflow and Infiltration (I&I).
Data collected from the meters showed that a lot of I&I throughout the older sections of the city in the Wheeling Street district is a significant source of direct storm inflow into the sanitary sewer.
Roman said plans call for the city to smoke test half of the sewers in the Wheeling Street district.
“The Wheeling Street district includes all the sanitary sewers from Coy Road west to the western corporation line. It’s the older sewer system of the city. It’s the older neighborhoods that we’re going to start out with,” he said.
The city will inform the public of the program this month and in July before the smoke tests begin in August, he said.
He showed council last Monday a draft brochure that gives the basic objective and definition of the I&I program.
“It’s very similar to the sidewalk program. We are hoping that we would actually start smoke testing in August, but we want people to understand better what we’re doing. We really need the months of June and July to do that.”
Illegal connections to sanitary sewers contribute to the problem, he said.
Some homeowners connect their downspouts underground to the sanitary sewer, which is illegal.
“It’s kind of sad that when it rains, our sanitary sewer system rises with the rain, as if it was a storm sewer. So we know there’s a lot of connections out there,” he said.
Homeowners can easily fix this, he said.
Downspouts can be disconnected and routed above ground and away from the home.
“Those are simple fixes. In areas where we have poor drainage, that is going to be more difficult. In areas that may not have storm sewers, we may be looking at assessed projects in order to improve the drainage system. It’s a lot of work. In order to be successful, we need to provide a lot of information up front, provide as much educational brochures as possible, and assist the public as best as we can. We know we will only be able to remove so much. That’s the reality. The EPA knows that. The idea is trying to reduce the size of it.”
The city received proposals from three firms to conduct the smoke tests, said Roman. He recommended Jones & Henry Engineers, Ltd., which provided the lowest cost and has experience with such tests. Council on Monday will consider approving the $34,367 contract with the firm.