Flushing Bay Remediation Dredging

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DETAILS

Client: New York City Dept. of Environmental Protection (NYCDEP)
Value: $37.5 Million
Project Date: Jan. 2017 – July 2018
Project Cut-sheet: Download

SUMMARY

Flushing Bay is located on the south side of the East River and stretches to the south near the neighborhood of Flushing, Queens. Flushing Bay and Flushing River have a long history of being used as dumping areas for sewage discharge and industrial waste. The bay, near Citi Field, between LaGuardia Airport and the neighborhood of College Point, is lined with 10 combined sewer outflows (CSO), part of the city's outdated sewer system, which connects sewage lines with the flow from storm drains during heavy rains, sending raw sewage spewing into area waterways. 

CASHMAN was selected to conduct the removal and disposal of ~76,000 cubic yards of CSO-impacted sediments from Flushing Bay. Other project work includes the placement of ~130,000 tons of clean fill to cover polluted mudflats including a specified cap area where pre-construction core samples showed elevated contaminants; the construction of a 100,000-square foot revetment system using articulated concreted mattresses placed under water to prevent shoreline erosion; and the planting of ~150,000 marsh plants, grasses, and trees to restore and beautify the upland area.


PROJECT HIGHLIGHTS

  • Work began in January 2017 with the removal of an existing dilapidated dock followed by the dredging operations, conducted using a CAT-385 and Sennebogen 870 mounted on Flexifloat platforms.
  • Dredged sediment was loaded into 30 foot x 60 foot hoppers and pushed to/from a second CAT-385 stationed on a deck barge, where it was transloaded into larger hoppers for delivery to the offsite processing facility.
  • Dredging operations were completed one week ahead of schedule in March 2017. Backfill operations commenced, using the same equipment resources. 
  • Revetment construction using a crew of divers began in May and continued until August 2017.
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