New Tunnels Under Hudson River
Now Collecting Water with PCBs
The horizontal tunnels, totalling about 1,500 feet, were built in the shape of a Y.
After more than 18 months of construction, GE has completed the finishing touches on an innovative tunnel system built in the bedrock near GE's former manufacturing plant in Hudson Falls. The system was built to capture the final drops of PCBs reaching the Hudson.
The work, which was performed with NYSDEC and NYSDOH oversight, was conducted in three main phases. First, GE expanded the capacity of the existing on-site water treatment plant from 125 gallons per minute to 450 gallons per minute. This enabled the plant to accommodate the additional water generated by the tunnels. GE also removed approximately 1,800 cubic yards of PCB-containing soils from a nearby vacant lot. The excavated soils were transported by truck to an approved off-site disposal facility.
Construction of the tunnels occurred next. First, a vertical shaft -- 24 feet in diameter and 200 feet deep -- was excavated in the ground at the site. Two horizontal tunnels -- totaling about 1,500 feet -- in the shape of a Y were then installed at the bottom of the shaft. The tunnels are 10 feet in diameter -- about the size of a railroad car -- and are situated 80 feet below the river. To break up the rock for construction of the vertical shaft and tunnels, a series of targeted, controlled blasts was conducted. More than 1,700 tons of rock were removed during the project.
The final stage involved the installation of approximately 20 collection drains in the tunnels. These devices allow groundwater to flow into piping in the tunnels, where it is collected and pumped to the expanded water treatment plant.
A diagram of the tunnel system and collection devices can be viewed by clicking here.
Now that the system is fully constructed and operational, crews will monitor its performance for a year to ensure it is operating as designed.
