Managing Invasive Phragmites and Restoring Natural Wetland Habitat

Non-native Phragmites australis, also known as Common Reed, is a species of perennial grass found across North America, especially along the Atlantic coast, in wetlands, riparian areas, shorelines, and other wet areas like roadside ditches and drainage basins. This aggressively invasive grass can grow up to 20 feet tall, in dense groupings, and tends to spread rapidly, quickly colonizing disturbed wetlands.

Once established, the invasive plant forms a monoculture with a dense mat, outcompeting native vegetation, lowering the local plant biodiversity, and displacing native animals. These landscape changes impair the natural function of the marsh ecosystem by altering its elevations and tidal reach. A higher, drier marsh leads to less vigorous growth of native salt marsh vegetation, allowing Phragmites australis to gain a stronger foothold and continue to take over.

USDA NRCS Plants Database phragmites illustrationPhragmites australis can also eliminate small, intertidal channels and obliterate pool habitat that offers natural refuge and feeding grounds for invertebrates, fish, and birds. The spread of invasive Phragmites australis also has negative impacts on land aesthetics and outdoor recreation by obscuring views and restricting access. And, each Fall, when Phragmites australis die off, the large concentrations of dry vegetation increase the risk of fast-spreading fires near highly populated residential and commercial areas.

Over the last century, there has been a dramatic increase in the spread of Phragmites australis, partly due to an increase in residential and commercial development that resulted in disturbances to wetlands. According to the U.S. Fish and Wildlife Service, the rapid spread of Phragmites australis in the 20th century can also be attributed to the construction of railroads and major roadways, habitat disturbance, shoreline development, pollution, and eutrophication.

Princeton Hydro has worked in areas throughout the East Coast to address and properly manage Phragmites australis in order to restore natural habitats and enhance plant diversity, wildlife habitat, and water quality. Two recent projects include the restoration of John A. Roebling Memorial Park in Hamilton and Pin Oak Forest Conservation Area in Woodbridge, New Jersey.

John A. Roebling Memorial Park

Mercer County’s John A. Roebling Memorial Park is home to the northernmost freshwater tidal marsh on the Delaware River, the Abbott Marshlands, an area containing valuable habitat for many rare species. Unfortunately, the area experienced a significant amount of loss and degradation, partially due to the introduction of the invasive Phragmites australis.

For Mercer County Park Commission, Princeton Hydro put together a plan to reduce and control the Phragmites australis, in order to increase biodiversity, improve recreational opportunities, and enhance visitor experience at the park. This stewardship project replaced the Phragmites australis with native species in order to reduce its ability to recolonize the marsh.

By Spring of this year, the team expects to see native species dominating the landscape from the newly exposed native seed bank with minimal Phragmites australis growth.

Pin Oak Forest Conservation Area

The Pin Oak Forest Conservation Area is a 97-acre tract of open space that contains an extremely valuable wetland complex at the headwaters of Woodbridge Creek. The site is located in a heavily developed landscape of northern New Jersey. As such, the area suffered from wetland and stream channel degradation, habitat fragmentation, ecological impairment, and decreased biodiversity due to invasive species, including Phragmites australis.

The site was viewed as one of only a few large-scale freshwater wetland restoration opportunities remaining in this highly developed region of New Jersey. A dynamic partnership between government agencies, NGOs, and private industry, was formed to restore the natural function of the wetlands complex, transform the Pin Oak Forest site into thriving habitat teeming with wildlife, and steward this property back to life.

This award-winning restoration project converted over 30 acres of degraded freshwater wetlands, streams and disturbed uplands dominated by invasive species into a species-rich and highly functional headwater wetland complex. The resulting ecosystem provides valuable habitat for wildlife including the state-threatened Black-crowned Night-heron and Red-headed Woodpecker. Biodiversity was also increased through invasive species management, which allowed establishment of native plants such as pin oak, swamp white oak, marsh hibiscus, and swamp rose. The restored headwater wetland system provides stormwater management, floodplain storage, enhanced groundwater recharge onsite, and surface water flows to Woodbridge Creek, as well as public hiking trails, all benefiting the town of Woodbridge.

Managing and Monitoring Phragmites

Scientific field research continues to be conducted in order to identify the best way(s) to manage and control the spread of Phragmites australis. Depending on the landscape and how established the Phragmites australis population is, there are several different methods that can be effective in reducing Phragmites australis infestations in order to allow for the regeneration of native wetland plant communities and protect fish and wildlife habitat.

Recently, a group of more than 280 scientists, resource managers and policy professionals gathered together at the Hudson River Estuary Program’s (HEP) annual conference to explore how natural and nature-based solutions (i.e. building living shorelines, enhancing tidal wetlands and stream corridors, and conserving vulnerable floodplains) can be used as critical tools for addressing the impacts of climate change while also protecting and enhancing critical habitat.

The conference included six interactive workshops and dynamic panel discussions. Christiana Pollack, GISP, CFM of Princeton Hydro, Terry Doss of New Jersey Sports and Exposition Authority, Kip Stein from New York City Parks, and Judith Weis of Rutgers lead a panel discussion, moderated by Lisa Baron from U.S. Army Corps Engineers, on “The Yin and Yang of Estuarine Phragmites Management” to share lessons learned over many years of combating invasive species, including how sea level rise is changing minds and techniques.

Together, representing decades of experience in Phragmites australis management and research, these experts presented the evolving nature of restoration for this habitat type, common control/management methodologies, and longterm management and monitoring strategies for this reed and other invasive species. During the panel discussion, Christiana made specific mention of the Roebling Park project as one example of successful strategies in action.

If you’re interested in learning more and seeing photos from a few recent Phragmites australis management projects, click below for a free download of Christiana’s full presentation.

Through a combination of prevention, early detection, eradication, restoration, research and outreach, we can protect our native landscapes and reduce the spread of invasive species. Learn more about our invasive species removal and restoration services.

 

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.

New Video Celebrates 50th Anniversary of Wild & Scenic Rivers Act

Credit: NPS.gov

Communities across the nation are preparing to celebrate the 50th anniversary of the Wild and Scenic Rivers Act. This landmark legislation passed by Congress in October 1968 safeguards the free-flowing character of rivers by precluding them from being dammed, while allowing the public to enjoy them. It encourages river management and promotes public participation in protecting streams.

As part of the celebration, the National Park Service released a new video highlighting a handful of ‘Wild and Scenic’ designated rivers in the Northeast – the Farmington, Sudbury, Assabet, Concord, and Musconetcong Rivers – along with the organizations and community volunteers who work together to protect and care for these rivers.

Princeton Hydro is proud to work with two of the river stewards featured in the video: Musconetcong Watershed Association (MWA) and Farmington River Watershed Association (FRWA).

The Musconetcong River:

Designated ‘Wild and Scenic’ in 2006, the Musconetcong River is a 45.7-mile-long tributary of the Delaware River in northwestern New Jersey.

Princeton Hydro has been working with MWA in the areas of river restoration, dam removal, and engineering consulting since 2003 when the efforts to remove the Gruendyke Mill Dam in Hackettstown, NJ began. To date, Princeton Hydro has worked with MWA to remove five dams on the Musconetcong River, the most recent being the Hughesville Dam.

As noted in the video, the removal of these dams, especially the Hughesville dam, was a major milestone in restoring migratory fish passage along the Musconetcong. Only a year after the completion of the dam removal, American shad returned to the “Musky” for the first time in 250 years.

“The direction the river is moving bodes well for its recovery,” said Princeton Hydro President Geoff Goll, P.E., who was interviewed in the 50th anniversary video. “This multidisciplinary approach using ecology and engineering, paired with a dynamic stakeholder partnership, lead to a successful river restoration, where native fish populations returned within a year. ”

The Farmington River:

The Upper Farmington River, designated as ‘Wild and Scenic’ in 1994, stretches 14-miles through Connecticut starting above Riverton through the New Hardford/Canton town line. The river is important for outdoor recreation and provides critical habitat for countless wildlife.

Credit: FWRA.orgBack in 2012, Princeton Hydro worked with the FRWA and its project partners to remove the Spoonville Dam. Built in 1899 on the site of a natural 25-foot drop in the riverbed, the dam was originally a hydropower facility. The hurricanes and flood of 1955 breached the dam, opening a 45-foot gap and scattering massive dam fragments in the riverbed downstream. The remnant of the main dam persisted for decades as a 128-foot long, 25-foot high obstacle in the channel. The river poured through the breach in a steep chute that stopped American shad from proceeding further upstream to spawn.

The project was completed, from initial site investigation through engineering assessment and final design, in just six months. The dam removal helped to restore historic fish migrations in the Farmington River (including the American shad) and increase recreation opportunities.

Wild & Scenic Rivers Act:

Credit: NPS.govAs of December 2014 (the last designation), the National ‘Wild and Scenic’ System protects 12,734 miles of 208 rivers in 40 states and the Commonwealth of Puerto Rico; this is a little more than one-quarter of 1% of the nation’s rivers. By comparison, more than 75,000 large dams across the country have modified at least 600,000 miles, or about 17%, of American rivers.

In honor of the 50th anniversary of the Act and in an effort to designate many more miles of river as ‘Wild and Scenic,’ four federal agencies and four nonprofit groups are coordinating nationwide events and outreach. Managing agencies are the Bureau of Land ManagementFish and Wildlife ServiceForest Service, and National Park Service, along with American RiversAmerican WhitewaterRiver Network and River Management Society. Go here for more info: www.wildandscenicrivers50.us.