Columbia Lake Dam Removal & Stream Restoration

In Northwest New Jersey on the Paulins Kill, an important tributary to the Delaware River, the century-old hydroelectric Columbia Dam was removed in 2019. The Columbia Dam was constructed as a Ransom hollow dam around 1906 and consisted of an 18-foot-high by 250 feet wide wall of structural concrete cells, a powerhouse, and 38-acre impoundment. The impoundment contained 300,000 cubic yards of sediment and was ~1.5 miles in length. Princeton Hydro was contracted by American Rivers to design and permit the removal, and contracted by The Nature Conservancy (TNC) to provide engineering oversight during the removal. Project partners also included U.S. Fish and Wildlife Service, NJDEP Division of Fish and Wildlife Service, RiverLogic Solutions, and SumCo Eco-Contracting. The construction was initiated in June of 2018. A passive sediment management approach was used, where ~17% of the accumulated sediment was deliberately allowed to mobilize downstream. The Delaware River was able to receive and transport this sediment with little or no adverse impacts to natural resource and recreational values. In April 2019, for the first time in over a century, American Shad returned upstream, just months after the main dam was removed. Prior to this removal, American Shad and other migratory fish could not make it past the large dam structure to swim upstream to their important breeding grounds. A true stream restoration success story! All aspects of the stream restoration and demolition were completed by fall of 2019.