Rockaway Line is a rapid transit line of the New York City Subway that connects Queens to the Rockaways, extending over Jamaica Bay. The section over Jamaica Bay was severely damaged during Hurricane Sandy on October 29, 2012, requiring emergency repairs. Through an existing on-call contract with the New York City Transit Authority, we were engaged immediately after the storm to perform a damage assessment and subsequent engineering design.

Based on a forensic assessment of the damage and analysis of metocean data recorded during the storm, it became clear that most of the rail embankment was completely inundated by Sandy’s storm surge, which exceeded the level for a 100-year (1% annual chance) event. Combined with wave impacts, the severe flooding destroyed rail infrastructure, covered the tracks with debris, and resulted in two large breaches along the embankment. NYCT determined that the rail line should be repaired and upgraded to reduce the risk of similar damage during future storms.

We recommended construction of a quarrystone revetment and sheetpile wall for wave protection, as well as a water transfer structure for more controlled discharge of storm surge runoff. We developed hydrodynamic numerical models for the design criteria needed for wave runup and loading analysis. The models were also applied for an adjacent impact study to assess the potential for wave reflection and other hydrodynamic processes to affect surrounding areas.

Following construction of the initial repairs, rail operation was resumed in May 2013.