After several failed proposals over the decades, the modern vision of the Passaic River Flood Tunnel took shape in the mid 1980s as the State of New Jersey selected a modified Army Corps of Engineers preferred alternative: The Pompton/Passaic Dual Inlet Tunnel Diversion Plan. The major elements of the proposed project were a 40-foot-diameter (12 m), 20.1-mile-long (32.3 km) tunnel and a 22-foot-diameter (6.7 m), 1.2-mile-long (1.9 km) spur tunnel, two inlets, one outlet, at least four workshafts along the tunnel pathway, "natural" storage areas, channel modifications, ponding areas, levees, and flood walls.[1] The outlet of the tunnel would be located in Newark Bay, 1,500 feet south of Kearny Point.
The 20.1-mile-long (32.3 km) main tunnel would carry flood waters from the primary inlet at the confluence of the Pequannock, Wanaque, Ramapo, and Pompton Rivers just above the junction with the Passaic River; an area that is most prone to severe flooding in the Passaic River basin. A 1.2-mile-long (1.9 km) spur would carry floodwaters from an inlet along the Passaic River, downstream from Two Bridges, to a connection with the main tunnel beneath the borough of Totowa, New Jersey. A Floodwarning and Forecasting System would be pressed into service to establish operating signals for the tunnel. Most of the major channel modifications would be built near the two tunnel inlets. The modifications would modify several portions of the Passaic, Pompton, Ramapo, Wanaque, and Pequannock Rivers. There are also two interim projects that would be constructed prior to the construction of the flood tunnel. These two projects include major stream alterations, including channelization to the Saddle River and Ramapo River. The cost estimate for the tunnel in the late 1990s was $1.8 billion.
