G2 provided engineering services during construction of a new 90 foot by 45 foot retention basin for the control of sewer overflow conditions on Belle Isle in Detroit, Michigan. In addition, a new wet well was constructed adjacent to the existing pump station that required approximately 20-foot deep excavation in a 20 feet by 26 feet footprint.

G2 provided the following services: Geotechnical Engineering, Vibration Monitoring, Pile Load Testing, Temporary Earth Retention Designs and Geotechnical Instrumentation


  • The primary concern was the deep excavation into soft clays resulting in excavation bottom instability.
  • G2 performed extensive geotechnical investigation to capture in-situ soil strengths, and implemented staged excavation techniques to provide a stable and efficient excavation system.
  • G2 provided geotechnical instrumentation including inclinometers, vibration monitoring and settlement markers to provide for early warning systems for any bottom instability hazards.