Notice Details

Contract CSO-GC-SFS-OH-CP2 is the second construction phase (CP2) in the overall construction of the OH-007 Gowanus Canal CSO Facility. During this CP2 phase, the below grade substructure of this facility will be constructed. In order to accomplish this, a cement-bentonite support-of-excavation groundwater-cutoff slurry wall will be constructed around the perimeter of the new facility along with braces across the footprint of the Facility. This will be followed by the excavation of soil within this perimeter where the new substructure will be built. Due to past industrial use of the site, the soil to be excavated is contaminated with hazardous materials. Air emissions will need to be closely monitored using a Community Air Monitoring Program to ensure that hazardous air contaminants are not released into the surrounding community during the excavation process. Additionally, a construction water treatment system will need to be constructed in order to treat and discharge groundwater that may be contaminated. Following excavation the water-retaining substructure will be constructed using cast-in-place concrete to provide durability, watertightness, and structural integrity. The substructure will include a screening area, five storage cells, an effluent channel, and a pump wet well to pump the stored CSO back to the main interceptor sewer in the area.