Capacity Restoration and Slope Stabilization of the Gull Island Confined Disposal Facility

The New Jersey Department of Transportation’s Office of Maritime Resources (NJDOT OMR) team developed an excavation and stockpiling plan to restore sufficient capacity at Gull Island Confined Disposal Facility (CDF) to support the required post-Superstorm Sandy dredging. Site investigation revealed a soft cohesive soil layer and relatively steep exterior slope up to 1.5 H to 1 V. A 4.5 m height stockpile with geotextile reinforcement was used to reach the desired capacity and slope stability, which was monitored by 5 inclinometers during the construction and dredging operations. Following construction protocols established by the OMR team, localized sloughing and seepage of the south dike was identified at the end of the 2016 dredging season, and an emergency slope repair program, using anchored turf reinforcement matting (TRM) and geomembrane, was conducted in early 2017. The repair successfully stabilized the south dike, with the CDF restored in time for the 2017 dredging season.