Owner:
Detroit Water and Sewerage
Department

Client:
Inland Waters Pollution Control

Prime Consultant:
NTH Consultants, Ltd.

NTH Project Budget:
$2.3 Million

Start Date:
August 2004

Completion Date:
Summer 2005

Emergency Sinkhole Repairs

Romeo Arm Interceptor Reconstruction

The Romeo Arm of the Macomb Interceptor, which provides 30-60 million
gallons of wastewater flow per day, was constructed in the early 1970’s to provide sanitary sewer service to the residents of Macomb County.

Project Scope
In August 2004, six homes were evacuated as a safety precaution when a 40-foot deep sinkhole developed over the Romeo Arm Interceptor in the city of Sterling Heights, Michigan. NTH was called to the site to stabilize the area, make preparations to ensure no interruptions to wastewater service, and to permanently repair the damaged interceptor.

Project Approach
Following on-site evaluations, it was determined the following procedures
would be necessary to stabilize, and repair the interceptor collapse:
  • Stabilize the sinkhole’s continued expansion by applying compaction grouting, jet grouting, caissons, and steel sheet pilings
  • Install multiple dewatering wells to remove ground water from the site
  • Design and construct a sanitary sewer bypass system around the damaged portion of the interceptor to ensure continued wastewater flow
  • Design and install two bulkheads inside the damaged interceptor to stop the flow of wastewater to the damaged area
  • Design procedures for permanently repairing the damaged interceptor

Working with several subcontractors, often on a 24/7 schedule, NTH
replaced the damaged portion of the interceptor by installing 23-pipe
sections measuring 8-feet long by 11-feet in diameter. Crews have now
removed the bulkheads in the interceptor and have back-filled the hole to a depth of 18-feet below road level. NTH will continue to provide field
engineering and QA/QC for this project through its completion. NTH is
working closely with the project team and with the owner, Detroit Water and Sewerage Department, to accomplish the repairs.