Hudson Falls TDCS
McMahon & Mann Consulting Engineers, P.C. (MMCE) was engaged by Ecology and Environment Engineering, P.C. (E&E) to provide geotechnical engineering consultation to the New York State Department of Environmental Conservation (DEC) on a project designed to collect polychlorinated by-phenols (PCBs) from the rock formation beneath the Hudson River. The potentially responsible party (PRP) designed a collection system consisting of a vertical shaft along the banks of the Hudson River, a series of tunnels extending from the shaft beneath the river and vertical drains extending from the tunnel crown into the rock formation containing the dense non-aqueous phase liquids laden with PCBs. One of the tunnels shown in the original design plans extended beneath a concrete dam that impounds the Hudson River for power generation at an adjacent plant.
MMCE reviewed the drawings, specifications and instrumentation plans proposed by the PRP and offered our advice to the DEC regarding the feasibility of the plans and the effect of the tunnel on the overlying dam structure. During construction, we observed the blasting events and rock excavation, reviewed the blast vibration and rock instrumentation data and provided our opinions to E&E and the DEC on geotechnical engineering issues.