American Shad Discovered Just Miles Upstream of Former Columbia Dam

Struggling fish species returns to spawning grounds for the first time in over a century, just months after dam removal completed

For the first time in over a century, American Shad (Alosa sapidissima) have been discovered upstream from the former Columbia Dam site on the 42-mile long Paulins Kill river, an important tributary to the Delaware River in northwestern New Jersey. Princeton Hydro’s Senior Water Resources Engineer and avid fisherman, Dr. Clay Emerson, PE, CFM, caught an American Shad in the Paulins Kill miles above the previous dam site this past weekend.

A successful collaboration between The Nature Conservancy, American Rivers, Princeton Hydro, U.S. Fish and Wildlife Service, and NJDEP Division of Fish and Wildlife Service, resulted in the removal of the out-of-commission hydroelectric Columbia Dam just months ago. 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.

“I was thrilled to feel the familiar hit and see the flash of an American Shad as I reeled the fish to shore. Being an avid shad fisherman and enthusiast, I knew the significance of seeing this beautiful fish back in a place where it’s always belonged,” said Clay. “We are thrilled to witness the American Shad return upstream so quickly after the century-old Columbia dam was removed. It’s a testament to the nearly instant benefits that dam removal has on the riverine ecosystem.”

The American shad’s return is an excellent sign of the overall ecological health and diversity of the river. Historically, dams, overfishing, and pollution have caused population decline in many of the major eastern U.S. rivers. American Shad, deemed the “Mid-Atlantic salmon,” are anadromous, which means they spend much of their lives in the ocean but return to rivers and their tributaries to spawn. This long distance swimmer makes it one of the Earth’s great travelers. After spawning upstream in rivers of the East Coast, American Shad migrate to their primary habitat in the Atlantic Ocean up in the Gulf of Maine. Unlike the salmon of the Pacific Ocean, American Shad may return to their spawning grounds multiple times over their lifetime. The species is a key prey species for many large fish and cetaceans like dolphins and whales in the Atlantic Ocean.

“The best indicator of river water quality improving in the Paulins Kill is the appearance of shad miles upstream from the Columbia Dam,” said Dr. Barbara Brummer, New Jersey State Director of The Nature Conservancy. “Today, we celebrate proof that with the 100-year dam impediment removed, they are once again successfully swimming up the river. I could not be happier! This is what teamwork and passion for nature can achieve. It is a great day for conservation in New Jersey, with many more great days for shad in the Paulins Kill to come.”

Princeton Hydro was contracted to investigate, design, and apply for permits for the removal of this dam as requested by American Rivers in partnership with the New Jersey chapter of The Nature Conservancy. The firm investigated, designed, and prepared the necessary permits for the dam removal. The team of engineers and ecologists studied the feasibility of removal by collecting sediment samples, performing bioassay tests, and conducting a hydraulic analysis of upstream and downstream conditions.

A view of the Columbia Dam at the beginning of the removal process.

“We are proud to be a part of this collaborative project, which has had an immediate and positive impact to the ecosystem of the Delaware River Watershed and its fishery resources,” said Princeton Hydro’s President Geoffrey Goll, PE. “Re-discovering this Delaware River diadromous icon upstream of the former dam is a very promising sign that the river will once again return to a major migration route and nursery for American Shad. This is why we do what we do!”

A view of the former Columbia Dam towards the end of the dam removal process.

This Columbia Dam Removal project could not have been possible without the hard work and dedication of the following partner organizations: The Nature Conservancy of New Jersey, American Rivers, Princeton Hydro, U.S. Fish and Wildlife Service, RiverLogic Solutions, NJDEP Division of Fish and Wildlife Service, and SumCo EcoContracting.

Anglers are reminded, according to New Jersey fishing regulations, except for the Delaware River mainstem it is illegal to fish for shad in any fresh waters of New Jersey.

Princeton Hydro has designed, permitted, and overseen the reconstruction, repair, and removal of a dozens of small and large dams in the Northeast. To learn more about our fish passage and dam removal engineering services, visitbit.ly/DamBarrier.

PHOTOS: Columbia Dam Removal

VIDEO: “Columbia Lake Dam when the water level was 18 inches to 2 feet lower”
Video courtesy of Matt Hencheck

In Northwest New Jersey on the Paulins Kill, an important tributary to the Delaware River, the century-old hydroelectric Columbia Dam is actively being removed. Princeton Hydro was contracted by American Rivers to investigate, design, and apply for permits for the removal of this dam for the New Jersey chapter of The Nature Conservancy. Our team of engineers and ecologists studied the feasibility of removal by collecting sediment samples, performing bioassay tests, and conducting a hydraulic analysis of upstream and downstream conditions. We’re excited to report that the Columbia Dam removal has officially commenced!

The New Jersey Department of Environmental Protection started draining water from Columbia Lake a few weeks ago, which was the first step in removing the dam. Princeton Hydro has subsequently been contracted by The Nature Conservancy to provide construction administration services.  Photos below show the water at lowered levels at the impoundments.

“Dewatering Impoundment” Photo by Princeton Hydro

“An aerial drone snapshot when water levels were down about 5 feet at the upper impoundment” Photo courtesy of the New Jersey Chapter of The Nature Conservancy

Last week, the first hammer hit the wall of a downstream dam remnant, officially starting the removal process.

“The first hammer”  Photo courtesy of Dale Bentz, RiverLogic Solutions

The dam removal process will last a few weeks, as the contractor actively knocks down the thick concrete wall.

“Pressure and time”  Photo courtesy of Dale Bentz, RiverLogic Solutions

“Halfway there”  Photo courtesy of Dale Bentz, RiverLogic Solutions

Once the dam is removed, there is a high probability that populations of American Shad and River Herring will be restored. It may also enhance American Eel migration. As a coldwater fishery, this reach also has significant potential for trout species, as well as Smallmouth Bass.

(Top) Before: Photo of the Columbia Dam before construction. (Bottom) After: Princeton Hydro’s rendering of what the river will look like once the dam is removed.

“It is very exciting to be a part of such a monumental effort for the restoration of the Paulins Kill. This river, once a major migration route for diadromous fish like American Shad, will once again be a nursery for this Delaware River icon,” said Geoffrey Goll, PE, President and co-founder of Princeton Hydro. “The removal of these dams will also restore the functions and values of a riparian corridor and floodplain, eliminate costs to the taxpayer for the maintenance of a dam and lake, and provide additional riverine recreational opportunities. I expect to see the same resilience and positive impact to the Delaware River as the recent barrier removals on another major NJ tributary, the Musconetcong River. It is a win-win for NJ, and with The Nature Conservancy at the helm and expert guidance from American Rivers, it has been an experience of a career.”

This project could not have been possible without the hard work and dedication of the following partner organizations: The Nature Conservancy of New Jersey, American Rivers, U.S. Fish and Wildlife Service, RiverLogic Solutions, NJDEP Division of Fish and Wildlife Service, and SumCo EcoContracting.

Princeton Hydro has designed, permitted, and overseen the reconstruction, repair, and removal of a dozens of small and large dams in the Northeast. To learn more about our fish passage and dam removal engineering services, visitbit.ly/DamBarrier.


This video from 2016 features the Nature Conservancy’s New Jersey State Director Barbara Brummer, Ph.D. speaking on the Columbia Dam removal. Video credit: NJ Herald.