City approves contract to replace sanitary sewer line

Authorizing city manager Amy Lange to enter into a contract with Nowak Construction for the repair/replacement of one block of sanitary sewer line from Olive to Spruce Street between Second and Third Streets at a cost of $81,479 to be paid from the Water Department fund was approved by the Concordia city commission during a special meeting on Friday.
Information presented to the commission stated that on June 12 the Utilities Department discovered a sinkhole in the alley between Second and Third Streets from Olive to Spruce. As they investigated, they found the clay pipe sanitary sewer line had collapsed, and as as they dug, it broke into pieces.
The water table is high, currently at about six feet below the alley surface. The soil is sandy soil, and as they dug to expose the pipe, the sidewalls of the hole collapsed further. A natural gas line and a phone line were exposed in the hole. A patch to the sanitary sewer main in the same alley was performed two years ago, 15 feet east of the hole.
There is a 20x40 foot hole in the alley over six feet deep. With the water table at six feet, there is no sanitary sewer line visible.
The sidewalls of the hole are continuing to cave in slowly.
One home is without natural gas service as their service was capped during a leak last Wednesday night.
Homes in the block are still using their sanitary sewer lines. One garage is blocked, though it is difficult to tell whether or not it is used.
The Utility Department shut off the upstream manhole so no upstream sewage is filing the hole, and crews will need to monitor and empty it with the vac truck as it fills so there are no backups.
The commission was informed that a traditional trench and replacement of pipe will not work well because of the high water table in the area and constant dewatering would be required, which significantly increases the cost of the project. Therefore, pipe bursting is the preferred method as it does not require open trenches.
It was stated that it is a complex and dangerous project.
The Kansas Department of Health and Environment (KDHE) supports the city's desire to replace the entire block of sewer line to mitigate the potential for further failures.
KDHE also supports the desire to make the repairs quickly.
The city obtained an engineer's estimate from Campbell & Johnson Engineers, PA last Thursday and solicited quotes from APAC, Nowak Construction and Smoky Valley Construction.
APAC did not respond to the request. Smoky Valley does not perform the pipe bursting methodology.
Nowak Construction responded with the quote of $81,479, which is $409 higher than Campbell & Johnson's estimate of $81,070, and can begin work today.