Okoboji Harbor – Section A

Section A work is the most intrusive part of the sewer rehabilitation project.  The Iowa Great Lakes Sanitary District is trying to minimize the impact to property owners as much as possible.  The main trenchless technology being used is pipe bursting.  Pipe bursting is a trenchless pipe replacement construction method. It is little more disruptive than pipe lining, but less disruptive than open cut replacement.  For pipe bursting all sewer service connections along the sewer main are dug up and disconnected.  Then a cable or rod is extended through the entire sewer main pipe section to be busted.  On one end of the cable a “spade head” is added that is larger than the existing pipe.  Connected to the back head is the new sewer pipe.  The head is pulled through using a winch machine breaking up the old sewer main pipe along the way.  The new sewer main pipe is pulled into the existing sewer main pipe cavity from behind and replaces the old pipe.  Once the new sewer main pipe section is installed the private sewer service lines are reconnected to the new sewer main pipe.  The final step is to connect the new sewer main pipe to the existing manholes and the replacement of the sewer main is completed.

Along with the Section A work, 14 manholes will be partially or completely replaced.  These manholes are in poor condition and will need to be replace in the next 5 to 10 years.  Instead of coming back to replace these manholes in 5 to 10 years, the Iowa Great Lakes Sanitary District is going to do all the work necessary with this project.  There is one location where a manhole will relocated.  There is another location where the distance between manholes exceeds the minimum requirements established by the Iowa DNR and a manhole will be installed to split this pipe distances.

Another part of the Section A work is to repair the sewer lift station found on Breakwater Drive.  This work will shut down at least one lane of traffic on Breakwater Drive.  The plan is to remove the top section of the lift station and rebuilt it in place.  This will help reduce the amount of water that is entering into the lift station through cracks and joints.  Other steps that are planned to take place in the area of the lift station is the installation of tile lines and storm sewer intake.  This will help reduce the puddling of the water in this area and keep the water out of the lift station.