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City Sewers Current Construction

Central Outfall Sewer (COS) at 59th Street and 4th Avenue Project

The COS rehabilitation project will include a number of improvements that will make your sewers more reliable for decades to come. 

The sewer and storm drain will be reconstructed at the intersection of 59th Street and Fourth Avenue to relieve sewage backup that is occurring in the 74th Street and Florence Avenue sewers. The City will work with project neighbors to ensure that traffic flow and access are maintained.


  • Construction period: fall 2012 through 2014. Weather or other circumstances could shift the work schedule. Neighbors will be informed as conditions warrant.
  • Construction cost: $2.1 million

  • A new storm drain siphon will be constructed to allow storm water to flow under the COS, and existing storm water from catch basins will be redirected downstream of the siphon. Existing sewers and the intersection will be reconstructed.

  • The project will involve a complete closure of the intersection located at 59th Street and 4th Avenue for the duration of the project. The City will announce alternate routes and additional information as the project progresses.

  • Construction methods include sewer pipe removal and replacement (performed by “open cut” or trenching, a method that is typically used where sewers are shallow).
  • Trucks and other equipment such as pipes will be used during construction, and you may see open trench excavation and debris removal.
  • Dust control will be provided in all project areas.
  • Enclosures or other barriers will be used in construction areas wherever necessary for public safety.
  • Flaggers will be used where traffic is impacted. Traffic will be restored to normal when construction has been completed at the end of each workday.
  • Trash pickup, deliveries, access to businesses and residential driveways will be maintained.
  • Parking may be temporarily restricted in some areas, and signs will be posted in advance telling you where and when.
  • You will be notified 24-48 hours in advance whenever sewer services may be temporarily interrupted.