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A green roof is a roof fully or partially covered in plants and waterproof media that helps reduce the volume and velocity of stormwater runoff from roofs by temporarily storing stormwater, slowing excess stormwater release, and promoting evaporation.

Green roofs offer many benefits. They can help regulate a building’s internal temperature, which leads to heating and cooling energy savings; reduce stormwater runoff; mitigate the urban heat island effect; and increase biodiversity. 

From the planted rooftop of a building in Berwyn, Pennsylvania, we spoke with Philadelphia Green Roofs Principal and Owner Jeanne Weber, BSLA, GRP about the basics and benefits of green roofs for stormwater management. Click below to watch:


To learn more about green infrastructure and stormwater management, check out our blog:

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In October 2021, the largest stream restoration in Maryland was completed. Over 7 miles (41,000 linear feet) of Tinkers Creek and its tributaries were stabilized and restored.

The project was designed by Princeton Hydro for GV-Petro, a partnership between GreenVest and Petro Design Build Group. Working with Prince George’s County Department of the Environment and coordinating with the Maryland-National Capital Parks and Planning Commission, this full-delivery project was designed to meet the County’s Watershed Implementation Plan total maximum daily load (TMDL) requirements and its National Pollutant Discharge Elimination System Municipal Separate Storm Sewer System (MS4) Discharge Permit conditions.

Today, we are thrilled to report that the once highly urbanized watershed is flourishing and teeming with life:

[gallery columns="2" size="medium" link="none" ids="10632,10631"]

We used nature-based design and bioengineering techniques like riparian zone planting and live staking to prevent erosion and restore wildlife habitat.

[gallery columns="2" size="medium" ids="10635,10634"]

10,985 native trees and shrubs were planted in the riparian area, and 10,910 trees were planted as live stakes along the streambank.

[gallery columns="2" size="medium" ids="10637,10636"]

For more information about the project visit GreenVest's website and check out our blog:

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The NJ Department of Environmental Protection (NJDEP) hosted its 3rd Annual Harmful Algal Bloom (HAB) Summit! The all-day, virtual seminar included expert presentations and facilitated open-forum discussions related to HAB science, monitoring, response, management, treatment and communication.

Approximately 220 people from around the country participated in the virtual summit, which was free and open to the public. The audience of stakeholders included government officials (local, state, federal); lake and other environmental commissions; watershed associations; environmental nonprofits; businesses; academics; lake management and HAB treatment experts; and folks interested in protecting their community lakes.

Participants heard presentations about “Keeping Your Pets Safe from HABs,” “The Benefit of Riparian Buffers;” and “Stormwater Management and the Use of Green Infrastructure.” Additionally, two members of the NJDEP HAB Expert Team - Dr. Fred Lubnow Director and Dr. Meiyin Wu - gave a presentation on best management practices to prevent, mitigate, and/or control HABs. The 10-person expert team was established as part of Governor Phil Murphy’s plan to enhance scientific expertise around water quality management and bolster the State’s response to HABs.

The Governor’s HABs Initiative was launched in 2019 after lakes throughout NJ (and the entire Continental U.S.) suffered from HAB outbreaks, which caused local and county health agencies to close off all beaches and issue advisories. These unprecedented conditions had significant negative impacts on lake-related ecological, recreational, and economic resources. The Governor’s initiative designated $13 million in funding to local communities for HABs reduction/prevention; established the aforementioned HABs expert team; and coordinated annual HABs summits in order to encourage continued community education and discussion.

If you were unable to attend the 2022 HAB Summit, NJDEP has made the complete morning and afternoon sessions available online:

Watch the Morning Session: 


Watch the Afternoon Session: 


The NJDEP Division of Water Monitoring and Standards has an entire website dedicated to HABs. Click here to access educational fact sheets, stay informed on HAB alerts and advisories, and report a HAB sighting.

For more information about HABs, watch a live interview with Dr. Fred Lubnow on Jersey Matters during which he discusses what steps should be taken to prevent HABs, and check out our recent blog:

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This year marks the 50th anniversary of the Clean Water Act. In celebration, The Watershed Institute launched its “Watershed Wednesdays” webinar series, which explores a variety of topics related to the environmental laws that arose after the Clean Water Act was instated. The webinars are free, open to the public and occur on the 3rd Wednesday of each month between 6 - 7:15pm EST.

To kick-off the Watershed Wednesdays series, three experts from the Princeton Hydro team led a workshop about “Stream Bank Restoration in Communities & Backyards,” which included three presentations and a Q&A session. Participants learned about what they can do to improve the water quality and restore the natural function of their neighborhood streams. Scroll down to watch the full webinar!

In the first presentation, Water Resources Engineer, Jake Dittes, PE, provides an overview of streams, how they flow, they’re natural evolution, how they’re being impacted by climate change, and the dynamic connection between land and water. Jake provides simple action items that everyone can do to reduce stormwater flow, limit runoff pollutants, boost and protect the natural floodplain.

Casey Schrading, E.I.T., Staff Engineer, shares examples of degraded stream systems, discusses a variety of restoration techniques, and talks about his experience with overseeing the largest stream restoration project completed in Maryland. He also provides helpful tips and examples of what individuals can do in their own backyards to promote stream bank stabilization.

The third presentation is given by Landscape Architect, Cory Speroff, PLA, ASLA, CBLP. In it he provides an in-depth look at a stream, floodplain and multi-functional riparian buffer restoration project Princeton Hydro completed at Carversville Farm in Western Pennsylvania. And, he provides an in-depth look at the native plants that were installed in various zones throughout the farm and how the different plants help reduce stormwater flow, absorb excess nutrients, and prevent erosion.

To view the full webinar go here:

Many thanks to The Watershed Institute’s Executive Director Jim Waltman and River-Friendly Coordinator Olivia Spildooren for hosting the webinar and inviting Princeton Hydro to participate. To learn more about the Watershed Wednesdays series and other upcoming adult-education events, click here.

The Watershed Institute, established in 1949, is a nonprofit organization located in Central New Jersey that promotes and advocates conservation and restoration of natural habitats, collects data on environmental conditions in its watersheds, and provides environmental education through numerous programs.

Princeton Hydro specializes in the planning, design, permitting, implementing, and maintenance of ecological rehabilitation projects. To learn more about our watershed restoration services, click here.

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Thousands of native flowering plants and grasses were planted at Thompson Park in Middlesex County, New Jersey. Once established, the native plant meadow will not only look beautiful, it will reduce stormwater runoff and increase habitat for birds, pollinators, and other critical species.

The planting was completed by community volunteers along with Eric Gehring of  Kramer+Marks Architects, Middlesex County Youth Conservation Corps, Rutgers Cooperative Extension of Middlesex County, South Jersey Resource Conservation and Development Council, and Princeton Hydro Landscape Architect Cory Speroff, PLA, ASLA, CBLP. 

All of the plants that were installed are native to the north-central region of New Jersey. Volunteers planted switchgrass (panicum virgatum), orange coneflower (rudbeckia fulgida), blue wild indigo (baptisia australis), partridge pea (chamaecrista fasciculata), Virginia mountain mint (pycnanhemum virginianum), and aromatic aster (symphyotrichum oblongifolium). In selecting the location for each of the plants, special consideration was given to each species' drought tolerance and sunlight and shade requirements. The selected plant species all provide important wildlife value, including providing food and shelter for migratory birds.

Photos provided by: Michele Bakacs

The planting initiative is one part of a multi-faceted Stormwater Treatment Train project recently completed in Thompson Park. The project is funded by a Water Quality Restoration 319(h) grant awarded to South Jersey Resource Conservation and Development Council by the NJDEP.

Middlesex County Office of Parks and Recreation and Office of Planning, NJDEP, South Jersey Resource Conservation and Development Council, Middlesex County Mosquito Extermination Commission, Freehold Soil Conservation District, Rutgers Cooperative Extension, Enviroscapes, and Princeton Hydro worked together to bring this project to fruition.

To learn more about the Thompson Park Zoo stormwater project, check out our recent blog:

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What is Stormwater Runoff?

Stormwater runoff is all of the rainfall or snowmelt water that is not absorbed into the ground and instead flows over land. When not managed properly, stormwater runoff causes issues like pollution in our waterways, flooding, and erosion. Stormwater runoff has been cited in multiple studies as a leading cause of water quality impairment to our local lakes and rivers. And, with increasing levels of rainfall from climate change impacts, stormwater management is an especially critical issue for communities all across the U.S.  

What is Stormwater Management?

Stormwater management focuses on reducing runoff and improving water quality through a variety of techniques. 

Traditional stormwater management methods include things like storm drains, retention ponds, and culverts. Green stormwater infrastructure uses vegetation, soil, and other natural components to manage stormwater. Green stormwater infrastructure systems mimic natural hydrology to take advantage of interception, evapotranspiration, and infiltration of stormwater runoff at its source. Examples include rain gardens, constructed wetlands, vegetated bioswales, and living shorelines.  Many stormwater systems include a combination of grey and green infrastructure management practices. 

Stormwater management treatment "trains" combine multiple stormwater management processes in order to prevent pollution and decrease stormwater flow volumes that negatively affect the receiving waterbody.

Let’s Take a Look at a Stormwater Treatment Train in Action

The Thompson Park Zoo in New Jersey

Thompson Park is a 675-acre recreation area - the largest developed park in the Middlesex County park system - with numerous attractions including playgrounds, ballfields, hiking trails, and a zoo. The zoo is an animal haven that houses over 50 geese and fowl, goats, and approximately 90 deer in a fenced enclosure. The park also features Lake Manalapan. 

Within the zoo is a 0.25-acre pond that impounds stormwater runoff from adjacent uplands and two stormwater-fed tributaries to Lake Manalapan and Manalapan Brook. There are three tributaries to the pond  with varying levels of erosion. The western tributary contains a headcut that is approximately four feet high. A headcut is created by a sudden down-cutting of the stream bottom. Similar to a miniature waterfall, a headcut slowly migrates upstream and becomes deeper as it progresses. The headcut in the Zoo tributary had destabilized the stream by eroding and incising its channel and banks. Additionally, foraging by Zoo inhabitants had removed most ground cover around the pond and associated tributaries, which also caused erosion. 

The bare soil conditions, headcut, and manure from the Zoo animals were contributing sediment, nutrient, and pathogen loading to the Zoo pond and subsequently Lake Manalapan. The Zoo pond drains to an outlet structure, a 24-inch reinforced concrete pipe (RCP), and subsequently to a vegetated swale via a stormwater outlet. A second outlet pipe drains stormwater runoff from an asphalt parking lot which discharges to the vegetated swale. 

The shoreline of Lake Manalapan where the vegetated swale drains into the lake was the subject of a previous restoration project during which a diverse suite of native plants was installed; however, the swale was not included in this project and a maintained lawn, which does not adequately filter stormwater runoff or provide any ecosystem services. The swale also had little access to its floodplain where vegetation can help filter non-point source (NPS) pollutants from the Zoo pond and adjacent uplands.

Implementing a Stormwater Management Treatment Train

In order to increase channel stability, decrease erosion, improve water quality and ecological function, and reduce the NPS pollutants originating from the Zoo, a stormwater management treatment train was designed and constructed. 

Middlesex County Office of Parks and Recreation and Office of Planning, the New Jersey Department of Environmental Protection (NJDEP), South Jersey Resource Conservation and Development Council (SJRC&D), Middlesex County Mosquito Extermination Commission, Freehold Soil Conservation District, Rutgers Cooperative Extension, Enviroscapes and Princeton Hydro worked together to fund,  design, permit,  and construct the following stormwater management measures: 

  • stabilizing the western tributary to Lake Manalapan and its existing headcut by constructing a rock step-pool sequence; 
  • installing BioChar filter bags within the Zoo pond to remove excess nutrients from the water column and bed sediments; 
  • daylighting a portion of the existing 24-inch RCP in order to widen the stream channel and allow for more stormwater absorption 
  • grading the vegetated swale to provide positive drainage and reduce mosquito breeding habitat; 
  • grading a floodplain bench adjacent to the swale to allow for increased water storage and absorption times and thus greater nutrient removal; 
  • installing outlet protection measures to reduce stormwater velocity and prevent scour within the swale; and 
  • replacing the manicured grass with native vegetation within transition areas to reduce erosion potential and increase biodiversity.

To see the project elements taking shape and being completed, watch our video:

The project is funded by a Water Quality Restoration 319(h) grant awarded to SJRC&D by the NJDEP for continued implementation of watershed-based measures to reduce NPS pollutant loading and compliance with a total phosphorus (TP) Total Maximum Daily Load (TMDL) established by the NJDEP for Lake Manalapan. The TMDL is a regulatory term in the U.S. Clean Water Act, that identifies the maximum amount of a pollutant (in this case phosphorus) that a waterbody can receive while still meeting water quality standards. 

“The South Jersey Resource Conservation and Development Council was pleased to participate in this project. Partnering with these various governmental agencies and private entities to implement on the ground conservation and water quality improvements aligns perfectly with our mission.  We are thrilled with the great work done at Thompson Park and look forward to continuing this partnership.”

Craig McGee, South Jersey Resource Conservation and Development Council District Manager

Construction of the stormwater treatment train components began in early August 2021 and was completed by the end of September 2021. 

The first step of the stormwater treatment train was to stabilize the tributary to Lake Manalapan and its associated headcut. Streambank stabilization measures included grade modifications to create a gradual stream slope and dynamically stable form with improved habitat features, including riffles and pools, with gravel and cobble substrate. On August 17, grading of the floodplain bench began, the RCP was exposed, and the team started  excavation for the lower three steps in the step-pool sequence.

On August 20, the rock grade and step-pool sequence were completed. And, fabric was installed along both sides of the rock-lined channel to increase stream-bank stability. Rock was placed within the pools to cover the edge of the fabric. We are very pleased to report that the newly restored channel held up to two large storm events during the construction process.

Bags of BioChar, a pure carbon charcoal-like substance made from organic material, were installed across the Zoo pond using an anchor and line system. The BioChar bags help to remove TP and other nutrients from the water column and bed sediments of the Zoo pond and subsequently Manalapan Brook Watershed. The team also built, planted and installed a floating wetland island, an effective green infrastructure solution that improves water quality by assimilating and removing excess nutrients that could fuel algae growth.

After conclusion of pipe lighting, excavation of the floodplain bench and installation of scour protection, native perennial vegetation was planted within the floodplain and swale in order to provide sediment deposition and nutrient uptake functions, as well as aquatic food web services and water temperature moderation before flows are discharged to Lake Manalapan. The plantings also enhance and create suitable avian and pollinator species habitat, and greater flora and fauna diversity.

This stormwater treatment train project improves the habitat and water quality of the Manalapan Brook Watershed by addressing NPS pollutants that originate from Thompson Park Zoo. The completed work also supports the Watershed Protection and Restoration Plan for the Manalapan Brook Watershed by reducing TSS and TP loads in compliance with the TMDL. Additionally, the project improves the overall ecosystem by stabilizing eroded streambanks, installing native and biodiverse vegetation, and reducing the quantity of pollutants entering Lake Manalapan. 

“Thompson Park Zoo is an excellent model for showcasing a successful and comprehensive approach to stormwater management and watershed restoration through a dynamic multi-stakeholder partnership. We are so proud to be a part of this project and continue to support the Manalapan Brook Watershed Protection Plan through a variety of restoration activities.”

Amy McNamara, E.I.T, Princeton Hydro Project Manager and Water Resource Engineer

At Princeton Hydro, we are experts in stormwater management; we recognize the numerous benefits of green infrastructure; and we’ve been incorporating green infrastructure into our engineering designs since before the term was regularly used in the stormwater lexicon. Click here to learn more about our stormwater management services.

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Over the past year, the Deal Lake Commission (DLC) has implemented a variety of stormwater management projects aimed at reducing the volume of stormwater runoff, decreasing total phosphorus loading, and preventing debris, sediment, and pollutants from flowing into waterbodies throughout the Deal Lake, Wesley Lake, and Sunset Lake Watersheds.

These projects encompass a strategic combination of stormwater best management practices (BMPs), including structural BMPs, non-structural controls, and green infrastructure techniques. These stormwater management projects were funded by a Clean Water Act Section 319(h) grant awarded by the New Jersey Department of Environmental Protection to the DLC.

Let’s take a look at some of the recently completed initiatives:


Manufactured Treatment Devices

Manufactured Treatment Devices (MTDs) are pre-fabricated stormwater treatment structures used to address stormwater issues in highly developed, urban areas. MTDs capture and remove sediments, metals, hydrocarbons, and other pollutants from stormwater runoff before the runoff reaches surrounding waterbodies and/or storm sewer systems.

This year, Princeton Hydro worked with the DLC and Leon S. Avakian Engineers to design and install three MTDs throughout Asbury Park, NJ with the purpose of improving water quality in Sunset Lake.

[gallery columns="2" ids="9896,9897,9894,9895"]  

Students from the Asbury Park High School Engineering Academy, led by their teacher Kevin Gould, were invited to observe one of the MTD installations. The educational field trip was combined with a presentation from Princeton Hydro’s Senior Aquatic Ecologist Dr. Jack Szczepanski, which was titled, “Ecology and Engineering in Asbury Park.”

Click below to watch one of the recent MTD installations: [visual-link-preview encoded="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"]  

Rain Garden Renovation

Rain gardens are a cost effective, attractive, and sustainable way to minimize stormwater runoff and filter out pollutants. This aesthetic, low-maintenance addition to any outdoor landscape creates a functioning habitat that attracts pollinators, beneficial insects, and birds. And, in a small way, it helps reduce erosion, promote groundwater recharge, and minimize flooding.

The DLC along with the Deal Lake Watershed Alliance, Asbury Park's Environmental Shade Tree Commission (ESTC), Asbury Park Department of Public Works (DPW) and Princeton Hydro completed a major renovation to an existing rain garden located in front of the Asbury Park bus terminal and municipal building.

The rain garden, which was originally constructed by the ESTC, was not functioning properly due to one of the inlets being completely obstructed by sediment. The DPW helped clear the sediment and regrade it, while the ESTC removed invasive weeds and replanted it with native shrubs, perennials, and flowers.

For more information about rain gardens and instructions on how to build your own, check out our recent blog: [visual-link-preview encoded="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"]

Floating Wetland Islands

Floating Wetland Islands (FWIs) are a low-cost, effective green infrastructure solution used to mitigate phosphorus and nitrogen stormwater pollution. FWIs are designed to mimic natural wetlands in a sustainable, efficient, and powerful way. They improve water quality by assimilating and removing excess nutrients that could fuel harmful algae blooms; provide valuable ecological habitat for a variety of beneficial species; help mitigate wave and wind erosion impacts; provide an aesthetic element; and add significant biodiversity enhancement within open freshwater environments.

The DLC worked with Princeton Hydro to design and install a total of 12 floating wetland islands, six in Sunset Lake and six in Wesley Lake. A team of volunteers, led by the DLC and Princeton Hydro, planted vegetation in each of the FWIs and launched and secured each island into the lakes.

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Clean Water Act Section 319(h) grant related efforts will continue in the Spring of 2022 with the design and installation of “bioscape” gardens and tree boxes. Stay tuned for updates!


To learn more about the Deal Lake Commission, click here. To read about one of Princeton Hydro’s recently completed stormwater management projects, click here.

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This article was originally published in the Musconetcong Watershed Association's "Instream Update" eNewsletter.

The Musconetcong River begins at New Jersey’s largest lake, Lake Hopatcong, and flows southwest for 42 miles before emptying into the Delaware River. At the headwaters in Lake Hopatcong, the community has been battling with harmful algal blooms (HABs). HABs can cause significant water quality issues in lakes and ponds, often forming a visible and sometimes odorous scum on the surface of the water. Blooms are primarily caused by warmer temperatures and increased amounts of nutrients (i.e., nitrogen and phosphorus) from stormwater runoff.

In 2019, the local community suffered immensely from HABs, which was the most prolific bloom the lake has experienced over the last two decades, resulting in public health advisories to be issued for recreation on the lake. Because Lake Hopatcong is a popular summer vacation destination, this outbreak unfortunately stunted the local economy, restricted recreational usage of the lake, and impacted fish and wildlife.

The Lake Hopatcong Commission and Lake Hopatcong Foundation, in partnership with municipalities, counties, the state, local groups like the Musconetcong Watershed Association, and Princeton Hydro, have been working to improve water quality for years by prioritizing stormwater mitigation and septic management policies within the watershed.  So why was the summer of 2019 so intense?

Analysis of 30 Years Water Quality Data 

Princeton Hydro scientists have been collecting water quality data in Lake Hopatcong for 30 years. This includes dissolved oxygen, pH, and temperature, as well as concentrations of total suspended solids, total phosphorus, nitrate‐N, ammonia‐N and chlorophyll a, and various biological factors. There are not many lakes in New Jersey that have such a robust and consistent public dataset, which presents a rare opportunity to study long-term trends. We dove a little deeper into this information to see what many have caused the 2019 blooms. 

We analyzed a statistically significant dataset of surface water temperatures and found that average July surface temperatures in Lake Hopatcong have been steadily increasing over time.  We also have 20+ years of observational data that documents an increase in frequency, duration, and magnitude of HABs over the same time period. In fact, HABs have recently persisted all the way into the winter months, enabling “green ice” to form on the lake surface, as observed in December 2020.

In summer of 2019, the Lake Hopatcong region was hit with a dramatic amount of rainfall. These weather patterns resulted in some of the highest early summer total phosphorus (TP) concentrations in Lake Hopatcong in over 20 years. The mean June TP concentration was 0.043 mg/L; the last time it exceeded 0.04  mg/L was in 1999. In order to have acceptable water quality conditions in the lake, the mean TP concentrations should be at 0.03 mg/L or lower.

It has been well documented that phosphorus is the primary limiting nutrient in Lake Hopatcong. Meaning, a slight increase in phosphorus can result in a substantial increase in algal and/or aquatic plant biomass. The water quality analysis identified the cause for the HABs (the high frequency of storms in June 2019 transporting nutrients, in particular phosphorus, to the lake) and identified why they persisted over the growing season (internal phosphorus loading).

Climate Change as a Driver for HABs

Climate change is leading to more frequent, more intense rainstorms that transport run-off pollutants into waterways, coupled with hotter days to warm the water. The latest Intergovernmental Panel on Climate Change (IPCC) report, “AR6 Climate Change 2021: The Physical Science Basis,” confirmed that human influence has warmed the atmosphere, ocean, and land, and that this human-induced climate change is already affecting many weather and climate extremes in every region across the globe.  It predicts, “increases in the frequency and intensity of hot extremes, marine heatwaves, and heavy precipitation, agricultural and  ecological droughts in some regions, and proportion of intense tropical cyclones, as well as reductions in Arctic sea ice, snow cover and permafrost.” In the Mid-Atlantic region of the U.S., most climate models indicate that the landscape will become warmer and wetter.

Looking at our observations and 30-year dataset for Lake Hopatcong, our preliminary analysis shows that climate change — increased precipitation (which flushed the phosphorus into the lake) followed by intense heat to warm surface water temperatures — was a significant variable that led to the devastating HABs at Lake Hopatcong in 2019. 

Other communities have experienced similar trends too. According to the U.S. Environmental Protection Agency, HABs have now been observed in all 50 states, ranging from large freshwater lakes, to smaller inland lakes, rivers, and reservoirs. Our neighbors in Upstate New York suffered from 1,000+ HAB occurrences during the 2019 season, including a HAB that covered 600+ square miles of Lake Erie causing beach closures and fish kills.

A study recently published in Nature journal reviewed three decades of high-resolution satellite data for 71 large lakes globally and determined that “peak summertime bloom intensity has increased in most (68%) of the lakes studied, revealing a global exacerbation of bloom conditions.” The study called for water quality management efforts to better account for the interactions between climate change and local hydrological conditions.

We are witnessing these impacts firsthand at Lake Hopatcong and within the Musconetcong River Watershed.  And, according to the IPCC report, these climate change-induced instances (i.e. intense rainfall followed by intense heat) may become even more frequent. To further understand the connection between climate change and HABs at Lake Hopatcong, Princeton Hydro is conducting a more rigorous study that includes more distinct data. We hope this will provide some insight on how to manage expected climate impacts in lakes and watersheds.

Taking Action in the Musconetcong River Watershed

While the IPCC report conclusions may be depressing, there is still much we can do at both a global and local level to limit future climate change. The key here is limiting cumulative CO2 (carbon dioxide) and CH4 (methane) emissions and quickly reaching (at least) net zero CO2 emissions. And, to specifically reduce occurrences of HABs While the IPCC report conclusions may be depressing, there is still much we can do at both a global and local level to limit future climate change. The key here is globally limiting cumulative CO2 (carbon dioxide) and CH4 (methane) emissions and quickly reaching (at least) net zero CO2 emissions. And, to specifically reduce occurrences of HABs fueled by climate change in Lake Hopatcong, eliminating sources of phosphorus from entering the lake is critical. So what can we do in the Musconetcong River Watershed?

In 2019, NJ Department of Environmental Protection committed $13.5 million via their Water Quality Restoration Grant programs for local projects that aim to improve water quality in New Jersey’s lakes and ponds. The Lake Hopatcong Commission landed a $500k grant via the program to evaluate and implement a variety of innovative, nearshore projects at Lake Hopatcong. Projects included performing an alternative non-copper-based algaecide treatment and one of the largest nutrient PhosLock treatments in the Northeast on the lake as well as the installation of Biochar bags, near-shore aeration systems, and floating wetland islands. 

This could not be possible without the help of all project partners including Lake Hopatcong Foundation, Morris County, Sussex County, Jefferson Township, Borough of Hopatcong, Borough of Mt. Arlington, and Roxbury Township, who collectively contributed over $330k in match support.  The Lake Hopatcong Commission also landed a subsequent $206,000 grant via NJDEP’s 319 program a few months later, with $44,000 in match support from the four municipalities and Lake Hopatcong Foundation and Commission, for the design and implementation of four in-lake/watershed projects to protect Lake Hopatcong's water quality.

The results of these projects were significant. Over the last two years, the mean June TP concentrations were lower than 2019 (0.033 mg/L in 2020 and 0.020 mg/L in 2021). These in-lake and watershed efforts have had a positive impact on reducing available phosphorus.

Just this month, Lake Hopatcong Commission landed another $480k from a National Fish and Wildlife Foundation Delaware Watershed Conservation Fund grant, which was backed with $489k more in match support from Lake Hopatcong Commission, Lake Hopatcong Foundation, Musconetcong Watershed Association, NJDEP, Borough of Hopatcong, Township of Roxbury, Mount Arlington Borough, Morris and Sussex Counties, Lake Hopatcong Historical Museum, Rutgers University, NJ Highlands Council, and Princeton Hydro.  The project team will design and implement three streambank stabilization projects in the watershed, which were identified as priority projects in the 2021 Upper Musconetcong River Watershed Implementation Plan. 

“Managing loads of phosphorous in watersheds is even more important as the East Coast becomes increasingly warmer and wetter thanks to climate change. Climate change will likely need to be dealt with on a national and international scale. But local communities, groups, and individuals can have a real impact in reducing phosphorous levels in local waters.”

Dr. Fred Lubnow, Director of Aquatics for Princeton Hydro

Changes in hydrology, water chemistry, biology, or physical properties of a lake can have cascading consequences that may rapidly alter the overall properties of a lake and surrounding ecosystem, which can lead to negative consequences like HABs. Recognizing and monitoring the changes that are taking place locally brings the problems of climate change closer to home, which can help raise awareness and inspire environmentally-minded action.

The Musconetcong Watershed Association is an independent, non-profit organization dedicated to protecting and improving the quality of the Musconetcong River and its watershed, including its natural and cultural resources. Since 2003, Princeton Hydro has been working with MWA in the areas of river restoration, dam removal, and engineering consulting. Click here to read our Client Spotlight blog featuring MWA’s Executive Director Cindy Joerger and Communications Coordinator Karen Doerfer.

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The Princeton Hydro team is proud to be participating in and sponsoring a variety events focused on conserving, restoring, and protecting our precious water resources. In this edition of our Events Spotlight, we provide a snapshot of upcoming events this Fall and information on how to get involved:


October 5: "Facebook Live" Q&A with Princeton Hydro HAB Experts

Do you have questions about harmful algal blooms? Now is your chance to get answers! Join us on Tuesday, October 5 at 6:30 PM EDT for a "Facebook Live" conversation with two of Princeton Hydro's HAB experts, Dr. Fred Lubnow and Mike Hartshorne. Participants will get an overview of HABs and engage in a live Q&A session. You can submit a question by joining the live feed and typing in the comments. Get more info and register.

October 11-15: SAME MEGA Maryland - Small/Minority Business Conference for A/E/C

This year’s conference features a mix of in-person and virtual events,  including informative keynotes; local, State, and Federal agency panels; networking sessions; training workshops; webinars; and two special field trip activities. Princeton Hydro is honored to sponsor MEGA Maryland, which is seen as the premier event for the architecture, engineering, and construction industry. Our Director of Marketing, Dana Patterson, will be exhibiting at the in-person portion of the event. Get more info and register.

October 13: NJ Invasive Species Strike Team Professional Conference

Presented by the Friends of Hopewell Valley Open Space and hosted by Duke Farms, the 2021 Annual New Jersey Invasive Species Strike Team Conference will focus on the use of prescribed burning to combat invasive species. Princeton Hydro is sponsoring this event, which is being held outdoors under a tent. We look forward to seeing you there in October! Get more info and register

October 14: Linden Blue Acres Tour - Green Infrastructure & Floodplain Restoration

Join NJ-AWRA and Princeton Hydro for a tour of the Award-Winning Linden Blue Acres Green Infrastructure & Floodplain Restoration Project. This project set the precedent for enhancing ecological and floodplain function on flood-prone properties acquired by the NJDEP Blue Acres Program. This event is approved for one (1) credit hour of continuing education for Certified Floodplain Managers. Get more info and register


October 18: Fall 2021 Regional Lake Communities Symposium 

Western Connecticut State University presents its Fall 2021 Regional Lake Communities Symposium “Fall Science at Night Virtual Seminar Series." The seminar, titled “Threats to Our Lakes: Beyond Aquatic Invasive Plants,” welcomes members of the public, students, and scientists to participate in a variety of workshops focused on local lake conservation and management. Princeton Hydro’s Director of Aquatic Programs Dr. Fred Lubnow is presenting “The Lake Hopatcong (NJ) Story.” Get more info and register

October 19-20: 2021 Living Shorelines Tech Transfer Workshop

Join Restore America's Estuaries, American Littoral Society, NJDEP and the Chesapeake Bay and New Jersey field offices of the USFWS for the Living Shorelines & Nature - Based Methods Tech Transfer Workshop. The workshop, which is being held both virtually and in-person at the Grand Hotel in Cape May, NJ, features field trips to local restoration projects, workshops, networking events, and an exhibit hall. Princeton Hydro is a proud sponsor of the event and our Director of Marketing & Communications Dana Patterson is exhibiting! Please note: Attendees must provide confirmation of COVID-19 vaccination as part of registration. Get more info and register

October 19-22: ANJEC 2021 Environmental Congress

We are thrilled to sponsor the 48th Annual Environmental Congress, which is being held in an all-virtual Zoom format. Each day includes a variety of workshop sessions on topics like stormwater management, environmental justice advancement in New Jersey, and local climate action. The closing session on Friday includes entertainment by Musician Maxwell Kofi Donkor. Get more info and register

October 26: Colorado Lake & Reservoir Management Association Conference

Princeton Hydro’s Senior Project Manager and Senior Aquatic Ecologist Chris L. Mikolajczyk, CLM, is giving a Halloween-inspired presentation titled "In Celebration of All Hallows Eve: Reflections of a Study on One of the Spookiest Lakes in the U.S." This free, one-day conference will be held virtually and is open to he public. Get more info and register

October 26-28: NJ Association for Floodplain Management 16th Annual Conference

The 16th Annual Conference will be held at the Hard Rock Casino Hotel in Atlantic City. With more than 40 speakers lined-up, conference workshops will focus on a robust array of floodplain management topics, including flood hazard identification and mapping; flood hazard mitigation; technical assistance and training; and natural resource protection and enhancement. Princeton Hydro is happy to sponsor this event and our Director of Marketing, Dana Patterson, will be attending and exhibiting. Get more info and register


November 1-4 and 8-11: Coastal & Estuarine Research Federation Biennial Conference

The theme of the 26th Biennial CERF Conference is "CERF at 50: Celebrating Our Past, Charting Our Future." The virtual, eight-day conference aims to connect science and society in the collective goals of preserving coastal and estuarine habitats, resources, and heritage. The conference, which is expected to draw 1,300+ scientists and researchers from all over the world, includes a virtual exhibit hall, networking events, a film festival and a variety of workshops. Johnny Quispe, Princeton Hydro Natural Resources Project Manager, is presenting on November 3 at 10 AM as part of the session on "Transdisciplinary design and adaptation for sustainable, resilient urban coastlines: realizing triple-bottom line outcomes." His presentation features The South River Ecosystem Restoration & Flood Resiliency Enhancement Project. Get more info and register.

November 3-5: Fifth Annual Watershed Conference

The Watershed Institute’s 5th Annual Watershed Conference will be in a hybrid format with participants selecting socially distanced, in-person sessions at the Watershed Center and Reserve or choosing to attend virtually if they prefer. Princeton Hydro is sponsoring the event and leading two workshops. Our Director of Green Infrastructure and Stormwater Management, Dr. Clay Emerson, P.E., CFM, along with Kathy Hale, Principal Watershed Protection Specialist, NJ Water Supply Authority, is presenting on “Naturalizing Detention Basins.” And, Vice President Mark Gallagher, along with Patrick Ryan of the NJDEP, is presenting on "Understanding Permit Requirements for Conservation Activities." Get more info and register.

November 6-10: American Fisheries Society Annual Meeting 2021

Science professionals from throughout the world will come together for this hybrid-format event offering both virtual and in-person participation opportunities. This year's conference, themed “Investing in People, Habitat, and Science” includes scientific sessions, a poster hall, a tradeshow and exhibits, and a variety of Plenary Speakers. Princeton Hydro President Geoffrey Goll is presenting on, "Dam Removal in History, Current State of Removal, and Future Needs." Get more info and register


November 9-10: Northwest New Jersey Rivers Conference

The Northwest New Jersey Rivers Conference is coordinated by the New Jersey Highlands Coalition, with the support of partner organizations in the Highlands and Ridge & Valley regions of New Jersey. Together, these groups are collaborating to restore water quality under the four-state Delaware River Watershed Initiative. The 2021 Conference, held in an online-only format, will focus on three key themes, "Sustainability & Economic Development," "Land Use Planning & Conservation," and "Water Quality Monitoring & Management." The conference is free and open to the public, and includes a variety of presentations, workshops and a virtual exhibitor hall. Princeton Hydro is exhibiting.  Get more info and register

November 15-18: North American Lake Management Society 41st International Symposium

Princeton Hydro is sponsoring the NALMS 2021 International Symposium, which will be held virtually. The event consists of multiple panels and discussions focused on the value of water for economics, ecology, and culture. Senior Project Manager Christopher L. Mikolajczyk, CLM is giving a presentation titled "A Public-Private Approach to Lake and Watershed Management in the Highlands Region of New Jersey.” Our Director of Aquatic Resources, Dr. Fred Lubnow, is presenting on "Monitoring and Management of HABs in New Jersey Waterbodies From 2019 to 2021." Get more info and register

November 21: Camden Environmental Summit

This one-day virtual summit, hosted by the The Camden Collaborative Initiative, focuses on preserving the environment in the city of Camden. Princeton Hydro is proud to sponsor this event, which is free for Camden residents and students, and $25 for all other attendees. Get more info and register.


Stay Tuned for More! 

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If you’re looking for a way to solve drainage issues in your yard and put rainwater to good use, look no further than a rain garden. Rain gardens are a cost effective, attractive, and sustainable way to minimize stormwater runoff and filter out pollutants. This aesthetic, low-maintenance addition to any outdoor landscape creates a functioning habitat that attracts pollinators, beneficial insects, and birds. And, in a small way, it helps reduce erosion, promote groundwater recharge, and minimize flooding


A rain garden is an excavated depression in the landscape that is planted with wetland or wet-tolerant plants. It captures a portion of stormwater runoff from a targeted area (i.e., rooftop, walkway, or driveway).  Even if it intercepts the first one inch of rain and the rest overflows, it will still capture about 90% of the total annual rainfall. 

The concept of rain gardens are becoming mainstream and there are many, many online resources to obtain design guidelines. In fact, even “This Old House”, a PBS stalwart, has an instructional page to help guide the design process!

"After repeated stormwater drainage issues near my home’s foundation due to flat topography, I opted to go the environmentally-friendly route of installing a rain garden in my front yard."

Princeton Hydro President Geoff Goll, P.E. recently installed a rain garden at his home and documented the process and put together step-by-step instructions on how to build your own:


Where does your stormwater flow? A rain garden is designed to infiltrate water, so it is best to build your rain garden in an area where rainwater will feed into it from downspouts, driveways or low points in your yard. 

  • At least 15 feet away from your home and downhill from any foundation.
  • Should not be placed over a septic tank or underground utility lines. 
  • Ensure there is a way to direct the rainwater runoff from the area to be treated (i.e., run a drainage pipe from a roof leader or grade the landscape so the water flows into the rain garden).
  • Keep it outside the drip line of any trees you want to keep. 
  • Do not select an area that is already wet due to high groundwater or an area that already receives water from other locations, so you do not overwhelm your rain garden, and divert other water away (it will defeat the benefit of the rain garden).
  • Consider the soil types. It is best to have soils that are sandy or silty sands. With compost added and blended in, a siltier type of soil can be improved too. However, clay soils are not conducive to a rain garden. A good source to check is the USDA National Database Mapping of Soils and/or dig down 2 feet to view the soils. Click here for a clear explanation for determining your soil type.


In order to determine if the soil at your selected location will readily infiltrate runoff, dig a few test holes. An optimal location will achieve one inch per hour of infiltration (i.e. the hole empties in 8 hours) and a good location will achieve one-half inch per hour (empties in 16 hours). If it is slower than 24 hours, you should consider a new location.

  • Dig a 12 inch diameter by 12 inch deep hole in the selected location.
  • Place a 12 inch ruler in the hole and fill it with 8 inches of water.
  • Record the total time it takes for the water to completely escape.


Determine the size and shape of your garden. Geoff chose a circular shape for his garden. 

  • Choose your shape.  A circular shape or kidney shape are the most common. 
  • Measure the total area to be treated (i.e. size of water coming rooftop or driveway into the rain garden). This can be done on foot, or even more quickly by finding your home on Google Earth and using the measuring tool. 
  • Choose how large the rain garden will be. A rule-of-thumb is to make the bottom surface of the rain garden 1/10th to 1/6th the size of the area to be treated. So, if you have an 800 square foot roof to be treated, the bottom area of the rain garden will be from 80 square feet to 133 square feet. (Note: Even if the size is 1/15th the area due to budget or location constraints, you are still doing good for the environment. Build on!)
  • Choose the appropriate depth of your garden. Generally, 6 to 8 inches of ponded depth is used. Using the runoff area calculations above and these depths, you can capture 85% to 90% of all runoff that occurs during the year, or about one inch of rainfall (in the Northeastern US). By capturing this much rain, the rain garden mimics the infiltration rate of a forest or meadow. What a great feeling, right?


IMPORTANT! Before you dig, you MUST call your state’s dig-safe number (811) at least 72 hours before putting a shovel in the ground. It’s the law! They will mark-out your property for free so that you don’t unintentionally dig into any underground utility lines.

Depending on whether you will hand-dig your rain garden (as Geoff did) or rent a small excavator (you can rent one from Home Depot or local equipment rental centers), will dictate how much time the effort will take.  Prepare your garden by removing all of the grass.  If you can, separate the topsoil for later use or for other areas of your property.

Start digging out the area until you reach the proposed bottom depth. In some cases, you may have to dig a little further down to reach more adequate soils for infiltration. The sides of the hole should form a gentle slope toward the middle and create a berm around the perimeter that ensures the garden will hold water in when it rains.

Tip: For excavated soil that’s not reused in your rain garden, find it a home by filling in low areas in your lawn or stockpile it for later use.


Carve out a spillway by creating a small indentation in the berm of the rain garden, lining it with permeable weed control fabric, and filling it with decorative stone.The spillway will allow excess rain water to overtop and flow out of the garden should it overfill during a storm event. 


Use some of the excavated soil to create a berm around the rain garden. Once depth for adequate infiltration is reached, begin filling the hole with sand, and continue to backfill it to the proposed final grade, making sure the bottom of the rain garden is 6 to 8 inches below the surrounding lawn. (Note: Geoff ordered 3 tons of sand for his project, however, this quantity will be custom to your site, so use your best judgement to determine how much you’ll need). Add leaf compost (about 4 lbs per square foot) to the top of the sand and hand-till the compost with a shovel to a depth of 12 inches.


Having native wetland or wet tolerant plants that can withstand periods of drought is the key to success. Use hardy perennial species with well-established root systems. For guidance, look to your local garden center and a niche plant nursery. Make the plant palette your own. (Note: Be on the lookout for deer resistant plantings if this is an issue in your area). 

When it’s time for planting, place each plant 12 inches apart and dig each hole twice as wide as the plant plug. The crown of the plant should be level with the ground.  Apply wood mulch over the bed. Water frequently until the plants are established. Later on, no watering will be necessary. The vegetation will fill in nicely over the next few seasons.


If you’re planning to connect your gutter to the rain garden, it’s a good idea to install the drainage pipe last so the project is not inundated with water after a rainstorm while it is still under construction. 

  • Dig a trench for a pipe that will carry water from one or more gutter downspouts to the rain garden.  (Tip: First peel up the turf over the trench, roll it up, and put it to the side. Once you backfill the area, you can simply roll the turf back. It is not a perfect method by any means, but the grass will grow back quicker than re-seeding.)
  • Line the trench with stones to prevent erosion. 
  • Install the PVC piping. Make sure the pipe has a positive slope for its entire length and that the spillway of your rain garden is at least 12 inches in elevation below the ground surface at your foundation so that water does not back up to the house during rain events. Use a level to make sure there is at least a ¼” per foot of pipe run. The slope keeps the pipe from collecting soil and debris and clogging. This will help prevent the water from shooting out of the connection between the downspout leader and your drainage pipe! 
  • Optional: Install a pop up emitter at least 10 feet from the house to allow any backed up water to safely drain away from the house. The emitter acts as a relief valve to allow water to discharge without getting to your foundation or basement.
  • Extend the piping into the rain garden basin by approximately one foot. 
  • When the piping is in place, fill in the trench with soil.


It is very important to keep an eye on your rain garden, especially after rain, to ensure that it is emptying in a timely manner. The last thing you want is to have the neighbors complaining about the “mosquito pond” next door. Generally, all the water should be infiltrated into the soil within 24 hours. 

“A week after I completed the installation of the rain garden, we received over 4 inches of rain within a 5 day period, and then, we were hit with Tropical Storm Ida with 4.29 inches of rain (from my home rain gage) in a period of less than 24 hours. The rain garden worked very well, and even after Ida, the rain garden infiltrated all the water retained in the bottom within an 8 hour period (about an inch per hour).”


Each season, pull weeds, remove debris, and replenish the mulch as needed in order to help retain moisture and block weeds. 

“During the construction, I’m sure my neighbors were judging the ugly hole in my front lawn. And, my wife even marked herself as “Safe from the Hole” on Facebook! However, when it was finished, she was pleasantly surprised at how pretty the rain garden looked and amazed at how it managed stormwater,” said Geoff. “If everyone in my neighborhood installed a rain garden, imagine the positive reduction in stormwater and flooding that would occur downstream.  Plus, we’d have some pretty awesome looking native flowers and grasses around for the pollinators and wildlife.”  

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Just 50 miles southeast of New York City, tucked between two municipalities, sits a 650+ acre tidal salt marsh which spans the shorelines of the South River in densely populated, highly developed Central New Jersey. The South River is the first major tributary of the Raritan River, located 8.3 miles upstream of the Raritan River’s mouth, which drains into Raritan Bay.

The Lower Raritan River and Raritan Bay make up a large part of the core of the NY-NJ Harbor and Estuary Program. Within the Raritan Estuary, the South River wetland ecosystem is one of the largest remaining wetland complexes. While the South River salt marsh ecosystem has been spared from direct development, it has been degraded in quality, and does not provide optimal habitat for wildlife or maximum flood protection for residents. This area is subject to fairly regular tidal flooding (particularly when it occurs simultaneously with a storm) and periodic—generally more severe—flooding during more significant events such as nor’easters and tropical storms. Hurricanes Irene and Sandy caused damage in the Boroughs of Sayreville and South River too.

In 2018, Princeton Hydro and Rutgers University, along with the Lower Raritan Watershed Partnership, Middlesex County, Borough of Sayreville, Borough of South River, NY/NJ Baykeeper, Raritan Riverkeeper, and the Sustainable Raritan River Initiative, secured funding from NFWF’s National Coastal Resilience Fund for the “South River Ecosystem Restoration & Flood Resiliency Enhancement Project.”

The South River Ecosystem Restoration and Flood Resiliency Enhancement Project aims to:

  • Reduce socioeconomic damages to the Boroughs of South River and Sayreville caused by storm damage, flooding, and sea level rise;

  • Transform degraded wetlands to high-quality marsh that can reduce flooding and enhance fish & wildlife habitat; and

  • Engage stakeholders in activities about coastal resilience and ecological health to maximize public outreach in the Raritan River Watershed.

For this 165-acre tidal marsh and transitional forest “eco-park,” the project team is conducting an ecosystem restoration site assessment and design. This phase of the coastal restoration project will result in a permit-ready engineering design plan that stabilizes approximately 2.5 miles of shoreline, reduces flood risk for smaller coastal storms, and enhances breeding and foraging habitat for 10 state-listed threatened and endangered avian species.

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Project Area History

This area has experienced repeated flooding, especially during large storms. For example, coastal areas of Sayreville and South River flooded after Hurricane Floyd (1999), Tropical Storm Ernesto (2006), Hurricane Irene (2011), and Hurricane Sandy (2012). Over the last century, there have been several studies and assessments completed for the South River, many of which identify this project area as a priority location for flooding improvements. The following are key reports and studies published about the project area and surrounding communities:

  • NJ Legislature’s 71st Congress published a report, “Basinwide Water Resource Development Report on the Raritan River Basin” which focused on navigation and flood control for the entire Raritan River Basin. It discussed recommendations for flood control and local storm drainage, setting the stage for future actions.

  • NJDEP Division of Water Resources published Flood Hazard Reports for the Matchaponix Brook System and Raritan River Basin, which delineated the floodplains in the South River, and its tributaries, the Manalapan Brook and Matchaponix Brook.

  • USACE New York District released a “Survey Report for Flood Control, Raritan River Basin,” which served as a comprehensive study of the Raritan River Basin and recommended several additional studies. Although the South River was studied, none of the proposed improvements were determined to be economically feasible at that time.

  • Project area was listed as one of the Nation’s Estuaries of National Significance.

  • USACE conducted a multi-purpose study of this area. This preliminary investigation identified Federal interest in Hurricane and Storm Damage Reduction and ecosystem restoration along the South River and concluded that a 100-year level of structural protection would be technically and economically feasible.

  • USACE NYD and NJDEP released a joint draft, “Integrated Feasibility Report and Environmental Impact Statement” for the South River, Raritan River Basin, which focused on “Hurricane & Storm Damage Reduction and Ecosystem Restoration.” Because it was previously determined that there were no widespread flooding problems upstream, the study area was modified to focus on the flood-prone areas within the Boroughs of Sayreville and South River, as well as Old Bridge Township.

Towards a More Resilient South River Ecosystem

Through collaboration with our project partners and following input provided from a virtual stakeholder meeting held in December 2020, Princeton Hydro developed a conceptual design for an eco-park that incorporates habitat enhancement and restoration, and protective measures to reduce impacts from flooding while maximizing public access and utility. Public access includes trails for walking and designated areas for fishing. The eco-park can also be used for additional recreation activities such as bird watching and kayaking.

Highlights of the conceptual design include the following features:

  • Approximately two miles of trails with overlook areas, connection to fishing access, and a kayak launch.

  • ~3,000 linear feet of living shoreline, located along portions of the Washington Canal and the South River, to provide protection from erosion, reduce the wake and wave action, and provide habitat for aquatic and terrestrial organisms.

  • ~60 acres of enhanced upland forest to provide contiguous habitat areas for resident and migratory fauna.

  • A tidal channel that will connect to the existing mud flat on the southeastern part of the site and provide tidal flushing to proposed low and high marsh habitats along its banks.

  • A vegetated berm with a trail atop will extend the length of the site to help mitigate flood risk.

  • Two nesting platforms for Osprey, a species listed as “Threatened” in NJ

  • Designated nesting habitat for the Diamondback Terrapin, a species listed as “Special Concern” in NJ

Princeton Hydro specializes in the planning, design, permitting, implementing, and maintenance of ecological rehabilitation and floodplain management projects. Click here to read about a coastal rehabilitation and resiliency project we completed in New Jersey.

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A green roof is a roof fully or partially covered in plants and waterproof media that helps reduce the volume and velocity of stormwater runoff from roofs by temporarily storing stormwater, slowing excess stormwater release, and promoting evaporation.

Green roofs offer many benefits. They can help regulate a building’s internal temperature, which leads to heating and cooling energy savings; reduce stormwater runoff; mitigate the urban heat island effect; and increase biodiversity. 

From the planted rooftop of a building in Berwyn, Pennsylvania, we spoke with Philadelphia Green Roofs Principal and Owner Jeanne Weber, BSLA, GRP about the basics and benefits of green roofs for stormwater management. Click below to watch:


To learn more about green infrastructure and stormwater management, check out our blog:

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