Celebrating the Columbia Dam Removal

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

On a bright, sunny day in Warren County, Princeton Hydro celebrated the Columbia Dam Removal Project with New Jersey Department of Environmental Protection (NJDEP) Commissioner Catherine McCabe, The New Jersey Nature Conservancy (event organizer), American Rivers, U.S. Fish and Wildlife Service (USFWS), NJDEP Division of Fish and Wildlife Service, RiverLogic Solutions, and SumCo Eco-Contracting.

Beth Styler-Barry, River Restoration Manager, New Jersey Nature Conservancy

Overlooking the soon-to-be removed, century-old, hydroelectric Columbia Dam, key stakeholders, including Princeton Hydro’s President Geoffrey Goll, P.E. and New Jersey Nature Conservancy’s Director Barbara Brummer, remarked on the success of the project, collaborative team efforts, and future benefits to the Paulins Kill habitat.

NJ Nature Conservancy’s River Restoration Manager, Beth Styler-Barry thanked project funders including NJDEP’s Office of Natural Resource Restoration, USFWS’s Fish Passage Program, National Fish and Wildlife Foundation’s Bring Back The Natives program, Natural Resources Conservation Service’s Regional Conservation Partnership Program, New Jersey Corporate Wetlands Restoration Partnership, Leavens Foundation, Tom’s of Maine, and Nature Conservancy members and donors.

“We made a commitment early-on to a 10-year monitoring and measurement plan. The removal of Columbia Dam is an opportunity to gain new knowledge and generate data that builds the case for this type of restoration. We’ll be looking at everything from mussels to temperature to geomorphological changes to increasing our targeted efficiencies. We’re also going to use images taken from repeated drone flyovers to look closely at changes in topography,” said Styler-Barry.

NJDEP Commissioner Catherine McCabe with NJ Division of Fish & Wildlife and NJDEP officials.

NJDEP Commissioner Catherine McCabe added, “The Columbia Dam is ranked in the top 5% of the nearly 14,000 dams that were assessed for priority. It will give us one of the most bangs for our buck in terms of fish and native species that we’ll be able to bring back up here.” She added, “This is exactly what Natural Resources Damages funds should be used for, and we are thrilled to see it come to fruition.”

Geoffrey Goll, P.E., President, Princeton Hydro

Back in the day, this dam structure was a marvel of engineering. Because concrete was very expensive during the time of construction, a patented, innovative “ransom hollow” design was used, which means it has a hollow center with series of doorways underneath the dam, explained Geoffrey Goll, P.E., President of Princeton Hydro. However, sustainability and climate change are very important issues today and must be taken into consideration for the life-cycle of a dam.

“Removal is a logical step in the history of this dam. Dam removals are the most impactful restorations. They provide the most ecological uplift and improvement for rivers,” Goll stated.

For Princeton Hydro, this project involved every discipline we have in the firm: civil engineering, fishery biology, wetland science, hydraulics, geotechnical engineering, and regulatory work. We were contracted by American Rivers to investigate, design, and permit for the removal of this dam for the New Jersey Nature Conservancy. Our team of engineers and ecologists studied the feasibility of removal by collecting sediment samples, performed bioassay tests, and conducted a hydraulic analysis of upstream and downstream conditions. Currently, we are providing construction administration services during the removal process. This project is a great example of our ability to complete multi-disciplinary projects in-house.

Project partners ready for the first hammer with the celebratory dynamite and sledge hammers.

At the end of the press conference, project partners celebrated the anticipation of the “first hammer” in the near future with an imitation dynamite siren and plastic sledge hammers. It was truly a keystone moment for everyone involved in this project.

The remnant dam downstream has already been removed and the main dam is due to be removed very soon. Check out our previous story with a series of photos documenting this first-step in the overall dam removal process: bit.ly/ColumbiaDamRemoval. Stay tuned for photos during the main dam removal process too.

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.

Conservation Spotlight: FORTESCUE SALT MARSH AND AVALON TIDAL MARSH RESTORATION

HABITAT RESTORATION THROUGH APPLICATION OF DREDGED MATERIAL

New Jersey, like other coastal states, has been losing coastal wetland habitats to a combination of subsidence, erosion and sea level rise. The New Jersey Department of Environmental Protection received a grant from the National Fish and Wildlife Federation to address this issue and rejuvenate these critical habitats. Grantees were charged with providing increased resilience to natural infrastructure that will in turn increase the resiliency of coastal communities in the face of future storms like Hurricane Sandy.

As a consultant for GreenTrust Alliance, a land conservancy holding company, Princeton Hydro worked with several project partners, including NJDEP, the US Army Corps of Engineers, NJDOT, The Wetlands Institute, and The Nature Conservancy, to increase the marsh elevation to an optimal range where vegetation, and the wildlife that depends on it, can flourish. One of the techniques used for this project included the use of dredged material disposal placement, which involves using recycled sand and salt dredged from navigation channels to boost the elevation of the degraded marsh.

A media statement from NJDEP further explained the process, “sediments dredged from navigation channels and other areas are pumped onto eroding wetlands to raise their elevations enough to allow native marsh grasses to flourish or to create nesting habitats needed by some rare wildlife species. Healthy marshes with thick mats of native grasses can cushion the impact of storm surges, thereby reducing property damage.”

FORTESCUE SALT MARSH

The salt marsh at the Fortescue project site is part of the Fortescue Wildlife Management Area. The specific goal of the project was to restore and enhance the interior high and low marsh, coastal dune and beach habitats.

To achieve these habitat enhancements, the Princeton Hydro project team first established biological benchmarks of each targeted habitat type and evaluated them to determine the upper and lower elevational tolerances for target communities and plant species. Approximately 33,300 cubic yards of dredged materials were used to restore a degraded salt marsh, restore an eroded dune, and replenish Fortescue Beach. The eroded dune was replaced with a dune designed to meet target flood elevations and protect the marsh behind it against future damage. The dune was constructed using dredged sand, and, to prevent sediment from entering the waterways, a Filtrexx containment material was used.

AVALON TIDAL MARSH

This project site is a tidal marsh complex located within a back-bay estuary proximal to Stone Harbor and Avalon. Princeton Hydro and project partners aimed to enhance the marsh in order to achieve the primary goal of restoring the natural function of the tidal marsh complex.

Two main activities were conducted in order to apply the dredged material to the impaired marsh plain: 1.) the placement of a thin layer of material over targeted areas of existing salt marsh to increase marsh elevations, 2.) the concentrated placement of material to fill expanding pools by elevating the substrate to the same elevation as the adjacent marsh. In total, dredged material was distributed among eight distinct placement areas throughout the property’s 51.2 acres.

These coastal wetland restoration activities will help to prevent the subsidence-based marsh loss by filling isolated pockets of open water and increasing marsh platform elevation. In addition, the beneficial reuse of dredged material facilitates routine and post-storm dredging and improves the navigability of waterways throughout the U.S.