Hudson River Isthmus Transloading Area (ITA)

CASHMAN DREDGING was issued a change order to the General Electric (GE) Hudson River Contract for the design, construction, and operation of a transloading facility (called the Isthmus Transloading Area or ITA). The ITA's purpose was to allow for the transfer of contaminated sediment dredged from a landlocked section of the Hudson River (a portion of the river between two dams which was not accessible by boat) across a spit of land to hopper barges staged in the Champlain Canal. Construction began in mid-February 2014 and had to be substantially complete by May 1, 2014, when the canals were flooded for the navigational season. The distinctive challenges of dredging in this landlocked section of the Hudson River called for a site-specific design and work plan. Lots of time was required to produce this site-specific design and work plan and to otherwise prepare for dredging in the landlocked area. Therefore, the dredging in the navigable portion of the Hudson river by-passed the landlocked area, causing significant vessel traffic in the landlocked area in 2014 and 2015.

PROJECT HIGHLIGHTS 

• An earthen embankment was constructed across the drained canal, followed by clearing, grubbing, and excavation of a 400'- long embayment to the canal to provide berthing for hopper barges outside existing navigational channel limits. Remaining construction activities consisted of preparation of sub-grade, placement of geomembrane liner, installation of decant and contact stormwater drainage systems, forming/placement of a 65' by 50' concrete slab with monolithic curbs for containment of sediments, erection of spill pans, and fender and bollard installation. 
• Once dredging activities began in the landlocked area, the transloading of sediment was performed utilizing two CAT MH3059 material handlers, each outfitted with a 2-yd³ TGS level cut bucket, stationed on either side of the containment slab. Dredge water was decanted from the riverside barges directly to the canal side hopper barges utilizing a 6" hydraulic pump and hose system. Storm and leachate water collected from the containment slab also was pumped directly to the canal side barges through a separate 4" sump pump.