I-90: Kellogg Dips
ITD continues to work with EPA to monitor any settlement and plan for emergency and long-term repairs to ensure the stability of the freeway underneath.
ITD continues to work with EPA to monitor any settlement and plan for emergency and long-term repairs to ensure the stability of the freeway underneath.
Four locations on Interstate 90 began to sink in February 2019, and since then, ITD has partnered with several agencies, including the Environmental Protection Agency, to determine the cause and prepare a permanent fix.
In the following months, ITD lowered the speed limit as necessary and twice added more pavement to keep the roadway surface level and increase speeds.
The cause of the settlement remains unknown, but with the completion of the EPA facility adjacent to the freeway in late summer 2020 and the forming of another dip in the westbound lanes, ITD will continue to monitor the area to assess the need for emergency repairs in fall 2020 or spring 2021.
Long-term repairs could include excavating 30 feet down to a weak spot below the pavement or reconstructing the ballast section to bridge this soft spot where the freeway is settling; options range from $5 million to $25.5 million, and a project could be added to the program in fall 2021 and scheduled for 2028 or sooner. Only time will tell the scope of repairs needed.
As of August 2020, a new dip has formed in the westbound lanes just east of the previous dips. At this time ITD is not expecting to lower the speed limit, but now that the EPA has finished the facility adjacent to the freeway, both agencies will continue to monitor the area to determine the need for short-term repairs and plan for any long-term repairs. Another layer of pavement could be added this fall or next spring if the settlement worsens.