It is formed south of the borough of Pompton Lakes by the confluence of the Ramapo and Pequannock rivers.[1] It flows south, passing between Lincoln Park and Pequannock Township (to the west) and Wayne (to the east). It enters the Passaic north of Fairfield Township at an area called Two Bridges.[2] Its watershed encompasses a section of the Ramapo Mountains along the New York-New Jersey border in the rural suburbs of New York City. It is the main tributary by volume of the Passaic. A portion of the river's water is diverted to the nearby Wanaque Reservoir.
The low-lying flat areas of Pompton Plains in Pequannock Township are prone to flooding from the Pompton River. In the wake of the heavy rains from Hurricane Irene in August 2011, the river overflowed, cresting at a record level of 25.54 feet (7.78 m) on August 29,[3] causing flooding that displaced hundreds of residents.[4]
The proposed Passaic River Flood Tunnel would alleviate flooding by taking water from the Pompton River in Wayne and sending it through a tunnel measuring 40 feet (12 m) in diameter for the 20 miles (32 km) to Newark Bay.[5]
^The Passaic River Basin, Montclair State University. Accessed February 1, 2024. "Shortly thereafter, the Passaic is joined by the Pompton River in Wayne in the 'Two Bridges' area. Here, near the Passaic-Pompton confluence, the North Jersey District Water Supply Commission withdraws from both rivers and pumps it to the Wanaque Reservoir. The Pompton River boasts a large, important watershed itself, claiming the Ramapo, Pequannock and Wanaque Rivers as tributaries. The Pequannock and Wanaque Rivers, both originating in the near pristine Highlands, support several very large drinking water reservoirs that serve millions of people in northern New Jersey."
^"Fairfield nixes all plans for Two Bridges Project; Concerned about additional traffic", New Jersey Hills, June 27, 2002. Accessed February 1, 2024. "Dreading additional traffic that would be dumped into Fairfield, and suspicious that the township is being set up by the New Jersey Department of Transportation to expand the Route 80 interchange there to relieve the "Spaghetti Bowl" junctions of Route 23, 46, and 80, Mayor Muriel E. Shore and council members rejected six alternate proposals for Passaic and Morris counties to improve traffic flow over the Pompton and Passaic River crossings. The area, known as Two Bridges, is at the confluence of the Pompton and Passaic rivers."
^Capuzzo, Jill P. "Pequannock, N.J., Challenged by Its Geography", The New York Times, September 30, 2015. Accessed February 1, 2024. "After Hurricane Irene in 2011, when nine inches of rain fell in less than 24 hours, causing the Pompton River to crest at a record 25.24 feet, more than a quarter of the town was submerged under several feet of water. Hundreds of families were temporarily displaced, and Mayor Cathy Winterfield said some are still recovering.... While the township’s flat plain made it an ideal site for the farmers who moved there some 275 years ago, and lends itself nicely to strolling today, its position at the low point where the Pequannock, Pompton and Wanaque Rivers meet has meant frequent, sometimes devastating flooding."
^Fact Sheet-Passaic River Mainstem and Tributaries, NJ, United States Army Corps of Engineers, December 14, 2023. Accessed February 1, 2024. "The major elements of the Mainstem flood damage reduction project are two underground tunnels, a 20.4 mile-long main tunnel 42-foot diameter and a 1.3 mile-long 23-foot diameter spur tunnel. The main tunnel would carry floodwaters from an inlet on the upper Pompton River in Wayne, New Jersey down to an outlet in Newark Bay."