Conservation Spotlight: Reducing Flood Risk and Restoring Wetlands in Jamaica Bay

Located in Queens, New York on the northern shore of Jamaica Bay, Spring Creek South contains approximately 237 acres of undeveloped land, including wetlands and 2.4 miles of coastline. The site is bounded by the Howard Beach residential neighborhood in Queens, a commercial area along Cross Bay Boulevard, the Belt Parkway, and Jamaica Bay. The northwest section of Spring Creek South is part of the National Park Service’s Gateway National Recreation Area, and is largely comprised of small patches of degraded tidal marsh and disturbed and degraded upland ecosystems.

On October 29, 2012, Hurricane Sandy drove a catastrophic storm surge into the New Jersey and New York coastlines. Spring Creek South and the surrounding community of Howard Beach experienced record flooding and damage to property and critical infrastructure. Storm tides caused damage and erosion along the shoreline and in the salt marsh area, degrading important habitat and leaving the site vulnerable to invasive species.

Hurricane Sandy Aftermath at Howard Beach, taken 10/30/2012 by Pam Andrade

The New York State Division of Homeland Security and Emergency Services (NYSDHSES) was awarded funding from FEMA’s Hazard Mitigation Grant Program to restore Spring Creek South. The U.S. Army Corps of Engineers (USACE) New York District, serving as project administrator, contracted Princeton Hydro to provide ecosystem restoration services. The goal of the project is to reduce future flood risk exposure while also protecting, restoring, and improving the quality and function of ecological systems; improving stormwater management and water quality; and enhancing the park’s visitor experience.

To achieve this goal, the project team is using an integrated approach that involves utilizing green infrastructure to create a natural barrier for the community and reduce the risks of coastal storms. Project activities include berm construction and the restoration of tidal marsh, creation of freshwater wetland forest, and creation of maritime shrub, forest, and grassland habitats, as well as stabilization of the existing shoreline.

On December 31, 2018, we completed Phase One of the project, which entails engineering design and preliminary permitting. More specifically, we’ve provided conceptual planning; analysis of subsurface soils for geotechnical properties and hazardous waste; coastal and freshwater wetland delineations; biological benchmarking analysis; and the development of sea level rise curves and two-dimensional hydrologic and hydraulic coastal modeling. As part of the hydrology study, we analyzed what the site could be expected to look like in 50 years due to climate changes and sea level rise. Our engineering design was also brought to 65% completion.

We also obtained permits, prepared the Environmental Assessment (EA), and oversaw the National Environmental Policy Act (NEPA) process. The EA received a “Finding of No Significant Impact” (FONSI) from FEMA, which means the environmental analysis and interagency review concluded that the project has no significant impacts on the quality of the environment.

Due to the complex nature of this project and its location, we are coordinating with a variety of different entities, including the local Howard Beach Community Board, the FAA (proximity to JFK International Airport), Port Authority, USACE, NOAA Fisheries, USFWS, USEPA, NYSDEC, NYC DEP, the National Park Service, HDR Engineering and WSP Engineering.

Phase Two of the project is the construction phase, which is expected to take about two years to complete. A key part of the Spring Creek South construction activities is the restoration of approximately 40 acres of tidal marsh, which is anticipated to improve water quality locally by stabilizing sediment, reducing erosion, and filtering dissolved particulate materials. The project team will restore existing coastline areas and install a salt marsh along the shoreline. Planted with native flora, like Spartina alterniflora, a perennial deciduous grass found in intertidal wetlands, the coastal salt marsh will help to stabilize sediment. Additionally, removing invasive species like Phragmites australis from the area and replacing it with native plant species will increase the ability for native vegetation to colonize the site, improve vegetative diversity, and reduce fire risk in the park.

A forested wetland area and berm will also be created in order to provide the surrounding communities with natural shields and buffers to future storms. The berm, with an elevation of 19 feet (NAVD88), will help to manage the risk of storm surge flooding caused by coastal storms. The forested wetland area will also provide improved stormwater runoff storage, naturally filter stormwater, and, via flap gates, direct its flow toward Jamaica Bay, away from residential and commercial properties.

These measures will help to dissipate wind and wave energy, increase shoreline resilience, improve stormwater management at the site, and create habitat that increases the ecological value and biodiversity at the site, while providing resilience benefits. Restoration activities will benefit vulnerable and rare ecological communities by producing localized environmental enhancements, including improving water quality and creating and restoring habitat. The project also increases opportunities for recreational uses such as wildlife viewing/photography, fishing, and nature study.

Princeton Hydro specializes in the planning, design, permitting, implementing, and maintenance of wetland rehabilitation projects. To learn more about some of our ecosystem restoration and enhancement services, visit: bit.ly/PHwetland.

 

Restoring the Northernmost Freshwater Tidal Marsh on the Delaware River

By Kelsey Mattison, Marketing Coordinator

Located in Hamilton Township, New Jersey, Mercer County’s John A. Roebling Memorial Park offers residents in the surrounding area a freshwater marsh with river fishing, kayaking, hiking, and wildlife-watching. The park contains the northernmost freshwater tidal marsh on the Delaware River, Abbott Marshland. Since the mid-1990s, many public and private partnerships have developed to help support the preservation of this important and significant marsh.

Tidal marshes, like the 3,000-acre Abbott Marshlands, contain valuable habitat for many rare species like River Otter, American eel, Bald Eagle, and many species of wading birds. Unfortunately, the Abbott Marshland has experienced a significant amount of loss and degradation, partially due to the introduction of the invasive Phragmites australis, or, Common Reed.

Phragmites australis

Phragmites australis is a species of grass that has a non-native invasive form that creates extensive strands in shallow water or on damp ground. The reed tends to colonize disturbed wetlands and then spreads very rapidly, outcompeting desirable native plant species. Once it is established, it forms a monoculture with a dense mat and does not allow any opportunity for native plants to compete. This impairs the natural functioning of the marsh ecosystem by altering its elevations and tidal reach which impacts plant and animal communities. Over the last century, there has been a dramatic increase in the spread of Phragmites australis, partly due to development impacts that resulted in disturbances to wetlands.

For the Mercer County, Princeton Hydro put together a plan to reduce and control the Phragmites australis, in order to increase biodiversity, to improve recreational opportunities, and to improve visitor experience at the park. This stewardship project will replace the Phragmites australis with native species with a goal to reduce its ability to recolonize the marsh. In September, our Vice President Mark Gallagher and Senior Project Manager Kelly Klein presented our plan to the public at the Tulpehaking Nature Center.

Vice President Mark Gallagher presenting on the project at the Tulpehaking Nature Center.

Princeton Hydro conducted a Floristic Quality Assessment to identify invasive areas and performed hydrologic monitoring to understand tidal stage elevations. Phase 1 of the restoration process occurred this fall and included herbicide applications to eradicate the Phragmites australis. The herbicide used, Imazapyr, is USEPA and NJDEP approved and our field operation crew applied it using our amphibious vehicle called a Marsh Master. For harder to reach areas, we used our airboat.

According to a USDA report, Imazapyr has been extensively studied, and when properly applied, it has no impact to water quality, aquatic animal life, birds, or mammals, including humans. It works by preventing plants from producing a necessary enzyme called acetolactate synthase.

The goal of this wetland restoration project is to enhance plant diversity, wildlife habitat, and water quality in John A. Roebling Memorial Park. In late spring of 2019, we will revisit the site to continue spraying the Phragmites australis. By Spring of 2020, we expect to see native species dominating the landscape from the newly exposed native seed bank with minimal Phragmites australis. Stay tuned for more photos from the field when our Field Crew returns to the site for Phase II in early Spring!   

View of John A. Roebling Memorial Park from the access road.

For more information about Princeton Hydro’s invasive species removal and wetland restoration services, visit: bit.ly/InvasivesRemoval 

Kelsey Mattison is a recent graduate of St. Lawrence University with a degree in English and environmental studies and a passion for environmental communication. Through her extracurricular work with various nonprofit organizations, Kelsey has developed expertise in content writing, storytelling, verbal communication, social media management, and interdisciplinary thinking. Her responsibilities at Princeton Hydro include social media management, proposal coordination, editorial overview, and other marketing tasks. As a member of the Princeton Hydro team, she aims to further its mission by taking creative approaches to communicating about our shared home: Planet Earth.

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.