Tishman Speyer

North Lake Dam Emergency Action Plan

Greenwich, CT

The North Lake Dam is located at the southern end of North Lake in Greenwich, CT. The concrete dam, 53-feet high and 543-feet long, serves as the foundation wall for the Greenwich American Center and its underground parking garage. The structure maintains a normal pool of 500 acre-feet of water with a maximum pool capacity of 800 acre-feet. Dam Owner, Tishman Speyer, retained Benesch to prepare an Emergency Action Plan (EAP) for the structure when it was designated as a “High Hazard” dam.

The EAP responded to the following purpose and scope.

1) To safeguard the lives of workers in the Greenwich American Center and reduce potential property damage within the dam’s flood or inundation area.

2) To provide for effective dam surveillance, prompt notification to local emergency management agencies and citizen warning and evacuation response, as required.

3) To identify emergency actions to be taken by the dam owner/operator, public officials and emergency personnel, as well as to outline response actions in the event of a potential or imminent failure of the dam. Separate Emergency Contact Lists were developed based on the nature and severity of the event.

The final plan was submitted to CT-DEEP for approval. The Greenwich American Center—with six underground levels—was designed using the dam as part of the building’s foundation and garage structure beneath it. Having an Emergency Action Plan in place is critical to maintaining the safety of everyone working at the site.

Project highlights

  • Hydraulic & Hydrology Analysis
  • Conducted Inundation Mapping
  • Developed Monitoring Procedure, Formal Warning
  • Notification Procedure & Evacuation Plan
  • Submitted Plans to CT-DEEP