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Princeton Hydro was formed in 1998 with the specific mission of providing integrated ecological and engineering consulting services. Offering expertise in natural resource management, water resources engineering, geotechnical design & investigation, and regulatory compliance, our staff provides a full suite of services throughout the Mid-Atlantic and New England states. We take great pride in producing high-quality products, which is achieved by our highly skilled staff. Our capabilities are reflected in our award-winning projects that consistently produce real-world, cost-effective solutions.

The Ecogeomorphic Evolution of Louisana’s Wax Lake Delta

By Brittany Smith, Environmental Scientist at Princeton Hydro 

As a graduate student in the geology program at the University of Texas at Austin, I worked on a study that used remote sensing to explore links between coastal geomorphology and ecology at the Wax Lake Delta in Louisiana. In this blog, I provide a snapshot of my research, which was recently published in the journal Remote Sensing.

 

What is the Wax Lake Delta?

The Wax Lake Delta is a small, young river delta in Louisiana that began growing in the 1940s after the construction of the Wax Lake Outlet. In 1941 the U.S. Army Corps of Engineers dug the Wax Lake Outlet from the Atchafalaya River – it extended out to the coastline and was designed to reduce the severity of floods in nearby Morgan City.

Image by NASA/Jesse Allen: While the Mississippi River Delta has been washing into the Gulf of Mexico and receding just to the west the Wax Lake and Atchafalaya River deltas (pictured above) are growing. Satellite imagery shows how the deltas have grown between 1984 (left) and 2014 (right).

This outlet provided a constant flow of water to be diverted from the river before reaching the banks of Morgan City, which had experienced several devastating floods. Approximately 40 percent of the Atchafalaya’s discharge gets channeled through the Wax Lake Outlet, which has the capacity to carry a maximum of 440,000 cubic feet per second.

Following the creation of the Wax Lake Outlet, the turbulent flow of water began to carry sediment down the outlet, which deposited at the mouth of the outlet and, over time, caused an underwater delta to grow. In just over 40 years, the Wax Lake Delta grew from nothing to an area twice the size of Manhattan. Research shows that it receives 34 million tons of sediment per year. Today, it spans roughly 7 miles out into the Gulf of Mexico and provides valuable habitat for a variety of animals.

 

The Why Behind the Research

Many coastal areas have been retreating or drowning as a result of subsidence and decreased sediment availability due to upstream dams and levees. According to the Population Reference Bureau, “Today, approximately 3 billion people — about half of the world’s population — live within 200 kilometers of a coastline. By 2025, that figure is likely to double.”

This population is increasingly vulnerable to flooding and erosion due to sea level rise and storms, especially in coastal Louisiana, where land loss is prevalent due to subsidence and decreased sediment supply.

The Wax Lake Delta is one of the few places in coastal Louisiana that is building rather than losing land, so is seen as an example of processes that could be applied elsewhere on the Gulf Coast to mitigate subsidence and restore coastal wetlands. Additionally, it is an ideal study site because it is relatively small, young enough that it has a good historic record, and has been largely unaltered by human activities.

This image depicts the study area: (a) The Wax Lake Delta (WLD, red square) is located at the terminus of the Wax Lake Outlet (blue line), which diverts water from the Atchafalaya River (purple line) in the U.S. state of Louisiana. The Atchafalaya is a distributary channel for the Mississippi (green line) and Red (red line) Rivers. (b) Image of WLD from 28-Sep-2010 by Landsat [88], for water level y = 0.35 m (NAVD88) at Camp Island gage (yellow dot) [93]. (c) Image of WLD from 24-Apr-2011 by Landsat [88], for water level y = 0.67 m (NAVD88) at Camp Island gage. WLD Pintail Island test case area outlined in white.

 

The Research in a Nutshell

Elevation is a very important variable in coastal ecosystems, as it controls how frequently a site is flooded. This in turn controls how frequently sediment can be delivered or removed from the site, and also what type of vegetation will grow there.

To understand how the Wax Lake Delta is growing, it would be ideal to have an understanding of how the topography has changed over time. Unfortunately, very little elevation data was available for the Wax Lake Delta, so I had to develop an indirect way of getting this information.

Photo Credit: Field and StreamWhat I did have available was a significant amount of Landsat satellite imagery. This was useful to me for two reasons: the delta is extremely flat and low-lying (less than 3 feet above sea level), and the tidal cycle typically fluctuates between 0-3 feet above mean sea level. This means that since each satellite image is taken at a different water level, different parts of the delta are exposed above the water in each picture. Taken together as a group over time, we can start to get a sense of which areas are higher and more likely to be exposed, and which areas are more likely to be flooded, and therefore at a lower elevation.

To do this in a quantitative way, I took all the images taken over a three year period and converted them to binary images, where land was classified as 1, and water classified as 0. I then added the images together, to create a composite image where pixels with higher values corresponded to areas that were exposed more frequently, and pixels with lower values were more frequently flooded.

Using water level data from a USGS gauge station that was installed at the delta in late 2008, I was able to develop a probability distribution of water levels. Taking these together – a probability map of flooding frequency and a probability distribution of water level elevations – I was able to create topographic maps based on the Landsat satellite imagery.

By performing this method over a number of years, patterns emerge about how the delta is evolving over time. The island changes from a relatively amorphous, unorganized shape to a defined outer levee and inner island platform.

Photo Credit: The National Wildlife FederationA deeper knowledge of the delta topography, allows us to look at connections to the delta ecology. We know that elevation controls hydrology and therefore plant growth, but we have also seen situations where plants can in-turn affect elevation by contributing organic matter to the soil, preventing erosion due to the root mat, or trapping sediment with their stems when sediment-laden water flows through.

In the case of salt marshes, previous studies have shown that if there is a feedback between the two, it occurs because a) plants tend to be most productive at a specific elevation and b) plants are in some way contributing to sediment accumulation relative to their productivity.

Photo Credit: USGSFor example, if a plant grows best at an elevation of two feet, it grows really densely at two feet, contributes more organic matter to the soil, bigger roots grow that help increase cohesion and reduce erosion, and the stems are denser and trap more sediment when the area is flooded. These all help increase the elevation of the marsh over time. However, if the elevation starts to get too high, the plant grows less densely, contributes less to the marsh surface, and the elevation will drop back down until the plant is happy again. Over time, the surface of the marsh will start to organize around these ideal elevations, creating a terraced effect with platforms corresponding to different plant types that do particularly well at that elevation.

When we look at how a transect down the center of the delta island has changed over time, we see that it goes from a relatively smooth, straight line, to a stepped system comparable to the models from other studies. When we compare the elevations of these platforms to the vegetation communities at the delta, we find that they correspond positively to high-marsh and low-marsh plants. This suggests that there is feedback occurring between plants and sediment accumulation at the delta.

 

In Conclusion

This research a) developed a new approach for investigating changes in coastal topography using satellite imagery, and b) confirmed that there is likely to be feedbacks between sediment deposition, marsh elevation, and vegetation growth. These feedbacks should be considered in any coastal wetland restoration and land building efforts.

 

Brittany Smith is an Environmental Scientist with an extensive background in hydrology and ecology. At Princeton Hydro, she has been involved in a wide variety of projects including stream assessments, wetland water budget modeling, soil field assessments, GIS analysis, permitting, and aquatic ecology. She holds a Master of Science in Geology with an emphasis in hydrology and geomorphology from the University of Texas at Austin, and a Bachelor of Science in Plant Biology from the University of California at Davis. Brittany has strong skills in data analysis and management, as well as experience in a broad range of field and laboratory techniques.

 

Community Science on the Schuylkill River

The nonprofit Schuylkill River Greenways, in partnership with Berks Nature, Bartram’s Garden, The Schuylkill Center for Environmental Education, Stroud Water Research Center, and Princeton Hydro, is kicking off a Water Quality Monitoring Project for the Schuylkill River on World Habitat Day, Monday, October 5, 2020. This project, focused on the main stem of the river from Berks Nature in Reading to Bartram’s Garden in southwest Philadelphia, is aimed to document the current ecological status and health of the river and seeks to engage and educate a diverse set of river users and residents.

“An important aspect of our mission is to connect communities to the Schuylkill River through recreational and educational activities,” said Tim Fenchel, Deputy Director of Schuylkill River Greenways. “To fully achieve the river’s potential, we must help the public understand the current health status and what they can do to continue to improve its quality for this generation and generations to come.”

In order to monitor the presence and/or distribution of litter along the Schuylkill River, the team is launching a campaign to recruit “Community Scientists” to conduct 5-minute Visual Monitoring Assessments. Using their mobile device, these volunteers can simply record the trash accumulation or dumping points along a 100-foot section of the Schuylkill River via a user-friendly form accessed via a cell phone: bit.ly/litterform.

“Trash is important to address when talking about the health of a waterway because it’s often the most visually obvious form of pollution. Bacterial and chemical pollution are generally less directly observable, but when we see trash, it instantly informs our impression of a body of water,” said Chloe Wang, River Programs Coordinator at Bartram’s Garden. “And, it can point to larger problems. For example, near Bartram’s Garden, a lot of trash washes into the river from combined sewer overflows, which also introduce harmful bacteria into the water. It will be interesting to see how the presence of trash differs along various stretches of the Schuylkill.”

The Community Scientist visual assessments require no formal training and are meant to be a simple effort that any resident can complete. We’ve developed an assessment survey, which can be accessed and submitted via a smartphone or tablet by opening the link in the phone/tablet’s browser.

“This is an opportunity for anyone with an interest in the Schuylkill River to spend time on the river and provide valuable feedback on the conditions of the river,” said David Bressler, Project Facilitator at Stroud Water Research Center. “Schuylkill River Greenways and its partners in this project are looking for motivated and dependable individuals to help them learn about the Schuylkill River and move in positive directions toward making the river more accessible to the community. Support from volunteers is very important and is greatly appreciated.”

The goal is to document critical areas of trash accumulation or dumping points in order to guide management efforts to better deal with this pollution. In addition to the multiple-choice questions to rank trash levels and quantities, this platform asks volunteers to submit a photo of the area and collects the GPS location. By utilizing this user-friendly platform, the data collected under this effort will be summarized and visualized by the project team.

“This project is an important study that we can use to connect people back to the river and show that the Schuylkill River is a place to be enjoyed by the entire community surrounding it and beyond,” said Michael Griffith, Education & Watershed Specialist at Berks Nature.

In 1985 the United Nations designated the first Monday of October every year as World Habitat Day. The idea is to reflect on the state of our towns and cities and the basic right of all to adequate shelter and to remind the world of its collective responsibility for the future of the human habitat. By understanding and improving water quality in the Schuylkill River, we are creating a place that enables community members to access public green and open spaces. This effort also supports UN Sustainable Development Goal 11, which aims for resilient, inclusive, safe, diverse cities by 2030.

In addition to the Community Scientist visual assessments, the stakeholder team is conducting water quality sampling and monitoring over the next year at four locations along the main stem of the Schuylkill River. This scientific documentation of critical water quality parameters will be performed by the stakeholder group’s employees and long term volunteers, who are trained in data collection and scientific methods. We will collect data on bacterial concentrations in the river using a combination of 3-M Petrifilm kits and laboratory-based analytical measures. In addition, in-situ temperature, oxygen, pH, and turbidity data will be collected utilizing Mayfly dataloggers.

“Our research shows that residents care about the river, but are not confident whether it is clean or safe to use for recreational activity. So we’ve designed a volunteer survey and scientific water quality assessment to document the ecological health of the Schuylkill River,” said Michael Hartshorne, Aquatic Resources Project Manager at Princeton Hydro. “By studying bacterial inputs and identifying hotspots for trash, we can communicate the status of the river, provide recommendations on areas of improvement, and ultimately, change the current public perception of the river.”

For the water quality monitoring, Princeton Hydro scientists will provide training to the partner nonprofit organizations’ staff and review the methods and protocols to assure the highest level of quality. This long-term data collection effort is slated to begin this month and continue for approximately one year. The results of this assessment will allow us to determine potential hotspots related to nutrient and bacteria inputs and to understand the overall ecological health of the Schuylkill River.

Overall, through this effort, the stakeholder team hopes to connect residents and communities with the Schuylkill River and to encourage engagement with this special resource.

Restoring Ballinger Lake Dam in Medford Lakes, NJ

Medford Lakes is a borough in Burlington County, New Jersey that consists of 22 lakes, and more than 10% of the homes there are log cabins. Located just 25 miles east of Philadelphia, within the New Jersey Pinelands Commission Management Area, the Borough is overseen by the Medford Lakes Colony (MLC), a homeowners association that manages social events and recreation activities for the community and also manages its “Lake Restoration Fund.” All homeowners in the community contribute to the Fund, which is used to manage and monitor lake water quality and maintain water control structures like dams and culverts.

Medford Lakes and its surrounding neighborhoods contain approximately 60 dams. The MLC retained Princeton Hydro to provide various engineering services for multiple dam structures throughout the Borough, including periodic visual inspections, dam breach and inundation analysis, and maintenance and repair work.

Ballinger Lake, located at the intersection of Lenape Trail and Stokes Road, contains a dam that is registered as a Class I – High Hazard Dam with NJDEP Division of Dam Safety. Immediately downstream from the dam is Main Street Medford Lakes, a congested portion of the Medford Lakes Borough.

The dam, originally constructed in the 1920s, is an earthen embankment dam with a clay core. Between 2000 – 2001, a reconstruction project took place that included the creation of both a primary and auxiliary spillway and a concrete culvert. The primary spillway consists of a concrete drop box and culvert that passes through the embankment. The auxiliary spillway, armored with articulated concrete block, is a low point on the embankment along Stokes Road.

In 2008, the Ballinger Lake Dam was inspected by Princeton Hydro and the NJDEP, Division of Dam Safety. The results of these inspections revealed considerable seepage at one of the concrete joints within the concrete culvert, a non-compliant trash rack assembly, a distressed gate valve assembly, and unstable downstream conditions.

Under Princeton Hydro’s direction, the lake was lowered to reduce the hydraulic load on the dam and to facilitate the required remediation and repairs. Princeton Hydro provided full turn-key engineering services that encompassed the development of the engineering documents and plans and preparation of all the permitting requirements (NJDEP Dam Safety, Pinelands Commission Certificate of Filing (CoF), NJDEP Dam Safety Emergency Permit, Burlington County Soil Conservation Erosion and Sediment Control, and NPDES permits). Our team also prepared the contractor bid specifications and provided construction oversight and management throughout the course of the repairs.

Throughout this process, Princeton Hydro completed multiple studies to characterize the hydraulic, hydrologic, structural, stability, geotechnical, and groundwater conditions at the dam under pre and post-repair conditions. The team eliminated the leakage and brought the dam back into compliance.  In 2019, MLC contracted Princeton Hydro to perform additional maintenance and improvements to the Ballinger Lake Dam spillway, outfall, and sluice gate.

The scope of work for the 2019 engineering and construction project included the following:

  • Replacement of the failed sluice gate structure
  • Installation of a baffled culvert extension on the downstream side of the existing culvert
  • Regrading of the downstream embankment to a shallower, uniform 3H:1V slope
  • Regrading of the levee crest to a uniform elevation
  • Riprap armament of the downstream channel
  • Various repairs to joints and spalls within the existing concrete dropbox and culvert structures.

The photo above, taken on September 23, 2019 by Princeton Hydro, shows a view of the lowered lake level and pumping intake hose.

Construction began on September 19, 2019 with the lowering of Ballinger Lake to facilitate the work within the existing dropbox structure. The lake lowering process was performed by a 6-inch centrifugal pump, which discharged water into the downstream channel. The photo above, taken on September 23, 2019, shows a view of the lowered lake level and pumping intake hose. After the lake was lowered below the dropbox crest, all of the concrete was power washed and work began to waterproof and repair all of the joints within the culvert.

The above photo, taken on October 17, 2019 by Princeton Hydro, shows the riprap being removed from the stream bed prior to pouring the flowable fill concrete mud mat.

In October, the team began removing portions of the existing stream bed riprap in preparation for pouring a flowable fill-based mud mat to level the foundation of the culvert extension. The area was dewatered with a submersible pump, with the discharge filtered through a sediment bag and directed back into the downstream channel at a point upstream of the installed turbidity barrier. The above photo, taken on October 17, 2019, shows the riprap being removed from the streambed prior to pouring the flowable fill concrete mud mat.

The above photo taken by Princeton Hydro shows the grate being prepared for the installation of the sluice gate valve operating mechanism.

The installation of the sluice gate valve support structure began in November 2019. Princeton Hydro oversaw the process to ensure the installation was being completed according to the design drawings and NJDEP Dam Safety regulations. The above photo taken by Princeton Hydro shows the grate being prepared for the installation of the sluice gate valve operating mechanism.

Photo taken on December 5, 2019 by Princeton Hydro showing the soil erosion mat being installed.

In December 2019, the team completed a topsoil application, seeding, and soil erosion matting installation to all disturbed areas of the site. All areas disturbed by construction activities (approximately 6,400 square feet) were graded to pre-construction conditions. The topsoil was applied to these areas and hand-raked to re-establish the original grades. The area was then seeded with perennial ryegrass, fertilized, and covered with a soil erosion mat. The above photo, taken on December 5, 2019, shows the soil mat being installed.

Following the final site inspection performed by Princeton Hydro in April 2020, we completed the Ballinger Lake Dam Spillway & Sluice Gate Improvements Closeout Report and presented it to MLC. The report confirmed that the site was considered stabilized in accordance with the approved project plans, the Standards for Soil Erosion and Sediment Control in New Jersey, and all NJDEP Bureau of Dam Safety requirements.

Princeton Hydro has designed, permitted, and overseen the reconstruction, repair, and removal of dozens of small and large dams in the Northeast. Click below to read about an emergency repair we completed on the Lake Wauwauskashe Dam. A concerning blockage developed in Lake Wauwauskashe Dam’s spillway and water was backing up at the upstream outlet structure causing a number of issues and potential hazards. Medford Lakes Colony, Princeton Hydro, and other project partners employed innovative solutions that lead to a successful emergency repair.

Creative, Timely Solutions Lead to Successful Dam Repair in Medford Lakes

To learn more about our dam and barrier engineering services, visit bit.ly/DamBarrier.

 

Dredging Children’s Pond to Restore Water Quality in Strawbridge Lake

Sedimentation in Children’s Pond, which is located in Strawbridge Lake park, was negatively impacting the water quality Strawbridge Lake. In order to restore the pond and reduce impacts to Strawbridge Lake, the Moorestown Township Council awarded contracts to Princeton Hydro for the dredging and cleanup of the Children's Pond.

Strawbridge Lake is located in Moorestown Township in Burlington County, New Jersey with portions of the watershed also extending into Mount Laurel and Evesham Townships. This 33-acre, tri-basin lake is a result of the impoundment of the confluence of Hooten Creek and the North Branch of the Pennsauken Creek that dates back to the 1920s.

Image by NJ.govThe lake receives surface runoff through Hooten Creek to the Upper and Middle Basins and the Lower Basin receives runoff from the headwaters of the North Branch of Pennsauken Creek. The lake then discharges back into another section of the North Branch Pennsauken Creek, which then flows into the Delaware River.

The watershed area that drains into the Strawbridge Lake is made up of an intricate mix of land uses: agriculture, new and mature residential subdivisions, office parks, major highways, retail stores, and large industrial complexes. The lake and the park area that surrounds it are heavily used for a variety of recreational activities.

Children’s Pond, which is located in Strawbridge Lake Park, is a popular fishing spot in the community. The pond initially functions as a wetland and drains from the northern portion of the watershed. Sedimentation—the naturally occurring process of the deposition and accumulation of both organic and inorganic matter in the bottom and/or banks of waterbodies—had significantly reduced the mean pond depth, thereby reducing the pond’s aesthetic appeal, impairing the fishery, contributing to eutrophication, and impacting the water quality of Strawbridge Lake. Sedimentation can also lead to contamination that poses a threat to aquatic plant and wildlife.

The dredging of Children’s Pond was identified by Princeton Hydro’s Lake and Watershed Management Plan and presented to the Moorestown Township Council’s environmental committee as one of a number of immediate actions needed in order to restore the pond, preserve the health of the watershed, and reduce impacts to Strawbridge Lake. Dredging, often used as an efficient solution for sediment removal, can expeditiously restore the waterway to its original depth and condition while also removing dead vegetation, pollutants, excess nutrients, and trash that may have accumulated.

Moorestown Township Council awarded contracts to Princeton Hydro for the dredging and cleanup of the Children’s Pond, which was an important part of the previously mentioned Watershed Management Plan for Strawbridge Lake.

Before the dredging could begin, a variety of surveys, field investigations, and data collection activities took place at the project site. A bathymetric survey is a critical component of any dredging project because it measures the depth of a waterbody, as well as maps the underwater features of a waterbody.

Due to the small area and shallow depths of Children’s Pond, the survey was conducted using a calibrated sounding rod and a Trimble GPS unit. The calibrated sounding rod was lowered into the water until it reached the top of the accumulated sediment. The location of the sample point and the water depth was then recorded with the GPS unit. Next, the pole was pushed down into the sediment until the point of refusal, and the bottom of sediment elevation was also recorded with the GPS unit. Data was collected from shoreline to shoreline at 25-foot transect intervals.

The data collected via the bathymetric survey, as well as the site survey, field investigations, and soil analysis, was used to shape the project’s engineering design and construction plans.

Before the dredging commenced, Princeton Hydro conducted a bathymetric survey to understand the depth and underwater features of a water body.

With the data collection process complete, Princeton Hydro was able to finalize the engineering plans and obtain all necessary permits for the project. Once the project commenced, Princeton Hydro oversaw the construction process and documented the project’s progress through Daily Field Reports (DFRs).

DFRs act as a living record of the project and provide the project’s key stakeholders with full details of the team’s daily performance and productivity, including arrival and departure times, the weather and temperature, equipment utilized on-site that day, a description of the work completed, and photographs of the work in progress.

This photo from the DFR on March 2, 2020 documents the beginning of excavation work in Children’s Pond:

This photo from the DFR on April 16, 2020 shows grading being completed on the west side of Children’s Pond: 

This photo from the DFR on April 20, 2020 documents the continuation (and near completion) of the excavation and grading work:

Princeton Hydro provides construction oversight services to private, public, and nonprofit clients for a variety of ecosystem restoration, water resource, and geotechnical projects across the Northeast. For more information, go here. And, to get an inside look at all that construction oversight entails, check out our blog:

A Day in the Life of a Construction Oversight Engineer

WATCH: NYSFOLA Hosts Free Lake Management Webinar Series

The New York State Federation of Lake Associations (NYSFOLA), in collaboration with Syracuse University Environmental Finance Center, hosted a four-part, educational webinar series on a variety of topics related to lake management. The goal of the webinar series was to bring together people involved with New York’s lake associations, as well as local government leaders to discuss management tips, understand more about their lakes and watersheds, and explore strategies around improving and protecting New York lakes.

The series concluded on July 23, 2020 with a webinar lead by Chris L. Mikolajczyk, CLM, Senior Project Manager, Aquatics of Princeton Hydro, and Jim Cunningham, NYSFOLA Board Member and the Town of Nelson, NY Supervisor.

In the webinar, titled, “Working with Local Government to Improve Lakes and Communities,” Chris presents a unique initiative lead by the Borough of Ringwood, which became the first municipality in the state of New Jersey to take a regional approach to private lake management through a public-private partnership (PPP) with four lake associations.

Chris provides an overview of The Borough of Ringwood, home to several public and private lakes, which took an active role in the management of its natural resources within multiple watersheds. He explains how the project came together and illustrates why a comprehensive, integrated approach to watershed and lake management is an incredibly important strategy to improve water quality for millions of people and reduce potential future incidents of aquatic invasive species and harmful algal blooms.

During Jim’s portion of the presentation, he discusses the role of local government in lake management and provides examples from projects and initiatives in Madison County, New York. To watch the recording of this webinar, click here.

The webinar series also included presentations about choosing the right liability insurance for a nonprofit organization; turning resource management-related conflicts into opportunities; and understanding lake science and water quality management. To access all of the webinars in the series, go here.

The New York State Federation of Lake Associations, Inc. was founded in 1983 by a coalition of lake associations concerned about water quality, invasive species, and other issues facing New York’s lakes. Today, more than 200 lake associations across the state are members of the only statewide voice for lakes and lake associations. NYSFOLA also has corporate members and individual members who support our efforts.

Princeton Hydro is the industry leader in lake restoration and watershed management. We have conducted diagnostic studies and have developed management and restoration plans for over 300 lakes and watersheds throughout the country. This has included work for public and private recreational lakes, major water supply reservoirs, and watershed management initiatives conducted as part of USEPA and/or state-funded programs. For more information about our lake management services, click here.

Dam Safety Recommendations for Tropical Storm Isaias

Tropical Storm Isaias Forecast. Source: NOAA

We, at Princeton Hydro, care for the health, safety, and well-being of our clients. We are tracking Tropical Storm Isaias closely as it heads up the East Coast, and the most recent precipitation forecast by NOAA is calling for a significant amount of rainfall in the NJ, PA, MD, NY region. Please be advised that the predicted precipitation could potentially pose a risk to your dam, pond, basin, or other structures.

For our clients who own and/or operate dams, levees, and other flood management structures, please take the following precautions, as adopted from a statement issued today by NJDEP Division of Dam Safety and Flood Engineering (see below), seriously:

  • For high/significant hazard dams, check your Emergency Action Plan to ensure that all contacts for emergency notification and emergency resources (engineers, contractors, supplies, etc.) are up to date.
  • Please refresh yourself regarding the dam owner’s responsibilities in the event of an emergency.
  • Please monitor your dam before, during, and after the storm event and report any concerns to your state Dam Safety office.
  • Prior to the storm, please take precautions to ensure that all spillways are clear of debris and that floating objects (boats, floating docks, etc.) which could block a spillway during high flow events are secured, where possible.
  • If you discover that a potential emergency condition exists at the dam, you should immediately contact your state Dam Safety office and the state emergency hotline. You must also contact your engineer, as well as implement your emergency action plan.
  • If your dam has any known vulnerabilities that you wish to discuss in advance of the storm, we recommend that you first contact your engineer. No modifications should be made to the dam without approval from your state Dam Safety office.

If you are a Princeton Hydro client and we provide inspection services to your dam, please reach President Geoffrey Goll, P.E. directly if you have any issues and/or concerns at 908-237-5660 ext. 103 or ggoll@princetonhydro.com. Even if it is after hours and you are concerned about the condition of your dam during this storm event, please do call Geoff directly. Safety is our priority and will do our best to assist you immediately.


State Dam Safety & Emergency Hotline Phone Numbers:

New Jersey:

  • NJDEP Division of Dam Safety and Flood Engineering: 609-984-0859
  • NJDEP Emergency Hotline 1-877-WARNDEP (1-877-927-6337)

New York:

  • NYSDEC, Division of Water, Bureau of Flood Protection and Dam Safety: 518-402-8185

Pennsylvania:

  • PADEP, Bureau of Waterways Engineering and Wetlands, Division of Dam Safety: 717-787-3411
  • PADEP Emergency Hotline: 1-800-541-2050

Maryland:

  • MDE, Water and Science Administration, Dam Safety Division: 410-537-3538
  • MDE’s Emergency Response Division: (866) 633-4686

Connecticut:

  • CT DEEP, Dam Safety Regulatory Program: 860-424-3706
  • DEEP’s Emergency Response Unit: 866-DEP-SPIL (866-337-7745) or 860-424-3338

***IMPORTANT MESSAGE FROM NJDEP***

DAM SAFETY PRECAUTIONS DURING TROPICAL STORM ISAIAS
POSTED: AUGUST 3,  2020 at 9:30 AM

 

This message is from the NJDEP, Division of Dam Safety & Flood Engineering. Based on weather forecasts, it has been determined that the potential for a significant rainfall event exists in the area of your dam. At this time, we are reminding high/significant hazard dam owners to check your Emergency Action Plan to ensure that all contacts for emergency notification and emergency resources (engineers, contractors, supplies, etc.) are up to date. Please also take a moment to refresh yourself regarding the dam owner’s responsibilities in the event of an emergency.

 

Please monitor your dam before, during, and after the storm event and report any concerns to this office. Prior to the storm, please take precautions to ensure that all spillways are clear of debris and that floating objects (boats, floating docks, etc.) which could block a spillway during high flow events are secured, where possible. If you discover that a potential emergency condition exists at the dam, you should immediately contact this office and our 24-Hour DEP Hotline at 1-877-WARNDEP (1-877-927-6337). You must also contact your engineer, as well as implement your emergency action plan.

 

If your dam has any known vulnerabilities that you wish to discuss in advance of the storm, we recommend that you first contact your engineer. You may also contact our office at the number below. No modifications should be made to the dam without approval from this office.

 

Please also be advised that the Division of Dam Safety and Flood Engineering does NOT recommend or require the lowering of impoundments prior to, during, or immediately following a storm event unless the integrity of the dam is in question. If a dam owner chooses to lower an impoundment for any reason, we encourage them to coordinate with local and county emergency management officials to ensure that any increased flow as a result of the lowering does not create flooding conditions downstream of the dam. The dam owner must also coordinate with the Division of Freshwater Fisheries (908-236-2118). A lake lowering permit (issued by Division of Freshwater Fisheries) is usually required prior to lowering.

 

Division of Dam Safety & Flood Engineering
NJ Department of Environmental Protection
609-984-0859

 

Click here for more information about Tropical Storm Isaias, visit NOAA’s National Hurricane Center and Central Pacific Hurricane Center.

Client Spotlight: Lake Hopatcong Foundation

This month we are launching the first blog in our Client Spotlight Blog Series! Each spotlight will feature one of our important client relationships in order to give you an inside look at our collaboration. We pride ourselves on forming strong ties with organizations that share our values of creating a better future for people and our planet. So we are excited to be able to share snippets of the incredible teamwork we’ve been able to accomplish over the years!

At Princeton Hydro, we value our client relationships, as the collaborative work we are able to complete with organizations like the Lake Hopatcong Foundation (LHF) reaches exponentially further than anything we could complete alone. One of the reasons our organizations have such strong symmetry is that our values align and complement each other.

As their mission states,”Lake Hopatcong Foundation dedicates itself to protecting the lake environment and enhancing the lake experience, bringing together public and private resources to encourage a culture of sustainability and stewardship on and around New Jersey’s largest lake, for this and future generations.” We are so proud to help protect New Jersey’s largest lake with LHF.

We have been working with LHF since its inception in 2012, which is why we are excited to feature them in our first client spotlight blog. We spoke with Jessica Murphy, President/Executive Director of the Foundation, and Donna Macalle-Holly, Grants and Program Director, to give you an insider look at the organization:

Q: What makes the Lake Hopatcong Foundation unique?

A: The Lake Hopatcong Foundation is unique in that our mission spans a wide spectrum of activities. In addition to projects that focus on the lake environment, we also take on initiatives that support education, safety, community-building, recreation, and even arts and culture. The lake is split between two counties and four towns, so bringing the community together for all these things is very important to us, in addition to making sure the lake itself is healthy.

Q: What does the Lake Hopatcong Foundation value?

A: During our strategic planning process, the board and staff developed a list of values that we go back to when operating and making decisions. They are:

  • Collaboration – We operate in a way that brings people together throughout the community.
  • Action – We are committed to our mission, moving quickly to take on projects that have an impact on and around the lake.
  • Sustainability – We are forward-thinking when making decisions, taking future generations into account when considering projects and initiatives.
  • Warmth – We are a friendly face to the community, showing the best of ourselves and bringing out the best in the people of Lake Hopatcong.

Q: How long have you been working with Princeton Hydro?

The Lake Hopatcong Floating Classroom ready for take off!

When we first started the Lake Hopatcong Foundation in 2012, Dr. Fred Lubnow was kind enough to do a water quality presentation as one of our very first events as an organization! In the years since, we’ve worked closely with Princeton Hydro, particularly in a support role as they conduct business with the Lake Hopatcong Commission. The Lake Hopatcong Commission is a state entity created in 2001 through the Lake Hopatcong Protection Act dedicated to protecting the water quality of Lake Hopatcong and to preserve the natural, scenic, historical and recreational resources of the lake. LHF funded Princeton Hydro’s water quality monitoring during the years that the Commission ran out of money

Q: What types of services has Princeton Hydro provided to your organization?

A: In addition to water quality monitoring on the lake, Princeton Hydro has led volunteer training for us in our efforts to prevent the spread of invasive species and to teach local students in our spring field trip program. Dr. Lubnow has also worked alongside us in applying for grants and in providing insight and expertise for other environmental projects at the lake, including helping guide the installation of floating wetland islands, and helping our NJ Lakes Group to work with NJDEP on Harmful Algal Bloom (HAB) policies. He even did a quick fact check on our children’s book, Lake Hopatcong Speaks Out, before we published it!

Q: Do you have a favorite or most memorable project we’ve worked on together?

Princeton Hydro’s Senior Project Manager, Christopher Mikolajczyk, CLM, presenting during a Water Scout training held by the Lake Hopatcong Foundation.

A: The days that Chris Mikolajczyk spent teaching our volunteers about how to find and remove water chestnuts from the lake were a lot of fun, particularly because we were kayaking on the lake for it! And, also because the kayak we provided Chris was too small for him, and he had to scrunch in to fit, but he was a trouper and paddled on.

Q: What are some exciting things your organization is working on right now?

A: We are working closely with Princeton Hydro and LHC on a series of projects, funded through NJDEP grants, LHC, LHF, and local governments, that we hope will prevent and mitigate HABs on the lake. Those projects include aeration systems, phosphorus-locking technologies, and stormwater infrastructure upgrades. We’re excited to see how effective each can be. Also, on August 7 at 12:30, Dr. Lubnow will be presenting the Lake Hopatcong water quality monitoring project results at LHF’s “Thirst for Knowledge” lunch-and-learn webinar series, which was created to share information and discuss topics of interest to our lake community. To register for the free webinar, visit lakehopatcongfoundation.org.

Photo by: Colleen Lyons of the Lake Hopatcong Commission

Photo by: Colleen Lyons of the Lake Hopatcong Commission

Q: What drives you to want to go to work every day?

A: All of us at Lake Hopatcong Foundation have a passion for this lake and want to see it protected; we have a love for the community that surrounds it, too. Jessica Murphy grew up on the lake, met her husband here, and now is raising her four children to love the lake, too. Donna Macalle-Holly also met her husband on Lake Hopatcong, lives on the lake, and has worked professionally to take care of it for nearly two decades. Everyone in our office has made memories on Lake Hopatcong and developed friendships with those who live and work here. Those personal connections fuel our passion for what we do.

Q: How can Princeton Hydro support you/your organization in the future?

A: Continue to be the incredible resource you are! We are so fortunate to have the deep knowledge and expertise that Fred and your entire team provide, and we look forward to continuing to work together in the years ahead.

Water Scouts paddling on Lake Hopatcong.


Some recent projects we are/have been working on with LHF include installing biochar bags to help control phosphorus levels and applying Phoslock to help mitigate harmful algal blooms! Because of our history working on Lake Hopatcong, we too have gained a passion for protecting and maintaining this lake. This incredibly important work could not be done without the genuine devotion and dedication from the Lake Hopatcong Foundation. We look forward to continuing great work with this incredible group!

Employee Spotlight: 4 Team Members Earn New Professional Certifications

Here at Princeton Hydro, we are dedicated to protecting our natural resources and changing our ecosystems, quality of life and communities for the better. As part of that, our team members are committed to continuing to learn new technologies, staying ahead of regulatory changes, and expanding their knowledge.

Today, we are proud to put the spotlight on four team members who recently achieved new professional certifications.

Senior Ecologist Michael Rehman PWS and Fluvial Geomorphologist Paul Woodworth are now Certified Ecological Restoration Practitioners (CERP) through the Society for Ecological Restoration (SER).

SER’s CERP program encourages a high professional standard for those who are designing, implementing, overseeing, and monitoring restoration projects. Only senior level practitioners who have achieved the knowledge requirements and have greater than five years of full-time experience with restoration can be certified. Michael is one of 15 people to hold a CERP certification in New Jersey, and  Paul is one of two people to be CERP certified in Connecticut.

Since he began working with Princeton Hydro in 2008, Paul has supported over 50 river restoration projects involving the removal of over 35 dams and barriers along the east coast. As a fluvial geomorphologist, he assesses streams to determine channel evolution processes and predict geomorphic responses to restoration actions.

This certification is a culmination of 25 years of hard work from undergrad, early professional jobs, grad school, and over 10 years of restoration work at Princeton Hydro. I had little idea that the course work I chose in undergrad was steering me toward a career in restoration that I didn’t even know existed at the time. SER has emerged as a top-notch organization with a global perspective on the proactive restoration of ecosystems and the sustenance of human communities. I’m excited about applying SER measures to our projects.

Michael has worked with Princeton Hydro since 2006. He is an expert in wetland permitting and delineations for USACE, NJDEP, and PADEP projects; wetland mitigation projects; habitat assessments; threatened and endangered species investigations; analysis of terrestrial/wetland ecosystems; municipal EIS/reviews and water quality/land use issues.

“Earning the CERP is a big achievement, and I’m proud to join the international network of credentialed professionals. I’m passionate about the restoration and enhancement of natural resources, and I have seen the transformation of brownfields to greenfields firsthand. Through the design and implementation of creative, nature-based solutions, my work will help advance the mission of SER and the field of ecological restoration.”

CERP is designed to ensure that certified practitioners are up to date on the new and important developments in the field of ecological restoration – both from the scientific and the practical perspectives. The certification is valid for 5 years after approval, and recertification requires that CERPs earn a minimum of 50 continuing education credits within the five-year period since they were last certified.


Both Emily Bjorhus and Robert George earned the Professional Wetland Scientist (PWS) certification through the Society of Wetland Scientists program.

The certification program was developed to meet the needs of professional ecologists, hydrologists, soil scientists, educators, agency professionals, consultants, and others who practice wetland science. This program is aimed at serving the public’s need to identify qualified individuals to assess and manage wetland resources around the world.

The PWS certification is awarded to those meeting specific educational and experience requirements: Minimum degree requirements are BA/BS, with course distribution of 15 semester hours each in biological and physical sciences and 6 hours in quantitative areas plus an additional 15 semester hours in wetland-related courses. In addition to comprehensive training in wetland science, a PWS is expected to have professional experience of at least five years as a wetland scientist, demonstrating the application of current technical knowledge dealing with wetland resources and activities.

As an Environmental Scientist, Emily Bjorhus works on a wide range of projects from flood risk management to wetland mitigation to stream restoration. She specializes in wetland and stream ecology and environmental permitting and compliance. Emily joined the Princeton Hydro team in 2016.

“I’m very proud of my Professional Wetland Scientist certification. I’ve been working in wetlands for the past six years and have a deep love of botany that makes my job a joy. I know this certificate will allow me to better serve the public’s need to have qualified individuals assess and manage wetland resources.”

Robert is a Project Manager in the Natural Resources Practice Area who provides technical expertise in environmental toxicology, wetland ecology, wildlife surveys, permitting and compliance for a variety of federal, state, and municipal ecological restoration projects. Robert has over twelve years of experience as a natural scientist.

“Certification as a Professional Wetland Scientist was important for me because this credential demonstrates to clients and local, state, and federal regulatory agencies that I am an experienced practitioner of wetland science with an educational and professional background that satisfied the rigorous standards of the Society of Wetland Scientists.”

Congratulations to Emily, Michael, Paul and Robert! 

For more information about SER and the CERP program, visit ser.org. To learn more about the Society of Wetland Scientists’ PWS program, visit sws.org. If you’re interested in learning more about the wide variety of engineering and environmental services Princeton Hydro offers, go here: princetonhydro.com/services.

Princeton Hydro’s Chris Mikolajczyk Featured in LakeLine Magazine

The latest issue of LakeLine Magazine, a quarterly e-magazine published by the North American Lake Management Society (NALMS), features an article written by Chris L. Mikolajczyk, CLM, Senior Project Manager and Senior Aquatic Ecologist with Princeton Hydro. Chris also contributed the beautiful photo that appears on the magazine’s cover.

In his article, titled, “A Regional Approach to Land Use Planning,” Chris discusses a unique project in Ringwood, New Jersey. The Borough of Ringwood is home to several public and private lakes. In order to take an active role in the management of these natural resources within multiple watersheds, the Borough of Ringwood was the first municipality in the state of New Jersey to take a regional approach to private lake management through a public-private partnership (PPP) with four lake associations.

Chris’ article provides an in-depth look at how the project came together; details the ongoing assessment and planning activities taking place; and displays why a comprehensive, integrated approach to watershed and lake management is an incredibly important strategy to improve water quality for millions of people and reduce potential future incidents of aquatic invasive species and harmful algal blooms.

“A regional approach to lake and watershed management is a normal approach from a scientific, technical, and community point of view,” writes Chris. “However, historically, state and municipal governments and private lake associations have rarely partnered to take such an approach in New Jersey.”

As the article states, funding for the Watershed-based Assessment for the Lakes of the Borough of Ringwood is being provided by the New Jersey Highlands Council through a grant reimbursement to the Borough of Ringwood. The Borough of Ringwood will review and, where feasible, implement any suggested actions surrounding the lakes, while the lake communities themselves will be responsible for any recommended in-lake actions, such as aeration, mixing, nutrient inactivation, etc., should they choose to implement them.

At the conclusion of the study, the final report provided to the Borough will identify and prioritize watershed management techniques and measures that are best suited for immediate and long-term implementation, as well as provide cost projections for implementation and maintenance in both the short-term and long-term.

To learn more, click here for the complete article and check out our recent blog:

BOROUGH OF RINGWOOD INITIATES FIRST-IN-STATE REGIONAL APPROACH TO LAKE MANAGEMENT THROUGH PUBLIC-PRIVATE PARTNERSHIP

The Summer 2020 issue of LakeLine, which was published as “open source” and is available as a free download on the NALMS website, is intended to serve as a general primer on lakes and empower environmental stewards in their efforts to safeguard the integrity of our surface waters.

NALMS was founded in 1980 as an organization with membership open to both professionals and citizens interested in applied lake management, while other organizations focused on either one or the other. From the beginning, NALMS has published LakeLine.

Princeton Hydro is the industry leader in lake restoration and watershed management. We have conducted diagnostic studies and have developed management and restoration plans for over 300 lakes and watersheds throughout the country. This has included work for public and private recreational lakes, major water supply reservoirs, and watershed management initiatives conducted as part of USEPA and/or state funded programs. For more information about our lake management services, click here.

Using Triploid Grass Carp to Control Aquatic Vegetation

Invasive aquatic weeds can create major impacts on freshwater ecosystems. One of the primary reasons invasives are able to thrive, spread rapidly, and outcompete native species is that the environmental checks and predators that control these species in their natural settings are lacking in the ecosystems and habitat in which they become introduced.

The subsequent damages they cause occur on many ecological levels including competition for food or habitat (feeding, refuge, and/or spawning), direct predation and consumption of native species, introduction of disease or parasites, and other forms of disruption that lead to the replacement of the native species with the invasive species. As a result, invasives often cause serious harm to the environment, the economy, and even human health.

Some of the more commonly occurring non-native aquatic plant species that impact East Coast lakes, ponds, and reservoirs include curly-leaf pondweed, eurasian watermilfoil, hydrilla, and water chestnut.

The introduction of triploid grass carp to freshwater lakes and ponds can be an effective solution and natural alternative to managing and mitigating aquatic weed growth. When stocked at a proper rate, at correct sizes, targeting proper plant species, and the right time, triploid grass carp can reduce or eliminate the need for chemical treatment of the water to control aquatic vegetation.

Originally from Asia, grass carp have been imported to the United States since the 1960s to intentionally release into controlled freshwater environments for aquatic plant control. Grass carp, which rely almost entirely on aquatic plants for their diet, prefer to eat many of the non-native aquatic plant species that negatively impact freshwater environments, including the aforementioned pondweed species and watermilfoil.

Triploid Grass Carp in Woodridge Lake

Woodridge Lake is a beautiful 385-acre freshwater lake tucked away in the hills of Litchfield County, Connecticut. The lake, which is fed by the Marshepaug River, is a man-made resource, with a dam at one end that allows the level of the lake to be controlled.

Woodridge Lake Property Owners’ Association (WLPOA) closely monitors the lake, conducting water sample testing on a weekly basis. As with all waterbodies, the lake experiences aquatic weed growth, some years worse than others due to a variety of factors including climate change.

As a method to naturally mitigate aquatic weed growth, WLPOA plans to introduce triploid grass carp to the waterbody. A study by the Connecticut Agricultural Experiment Station states that grass carp is “the only biological control used successfully in Connecticut.”

Since the grass carp are an introduced species, only triploid grass carp, which are sterile, can be used. This eliminates the possibility that the stocked fish can reproduce and overpopulate the lake, or if any were to escape the lake they could not affect other waterbodies. As an additional measure of protection, to ensure that the carp remain in the lake, a screen, or emigration control device, is required. Princeton Hydro, in partnership with WLPOA, Rowledge Pond Aquaculture, and CTDEEP recently completed the installation of a carp screen.

The screen, which was custom designed by Princeton Hydro, is located in the outlet structure of the Woodridge Lake Dam, downstream of the spillway crest and within the concrete stilling basin of the spillway structure. Subsequently, the installation and operation of the carp screen will have no impact on spillway capacity or water surface elevations at the spillway crest. In addition, there will be no impact on the flow capacity or the water surface elevations of the Marshepuag River downstream of the dam outlet structure.

The emigration control device is a modular, vertical-bar screen composed of eight sections. A modular screen design was chosen to facilitate off-site fabrication and easier installation, as well as repair of an individual section, if necessary. Installed, all eight sections transect the entire 40-foot width of the spillway structure.

WOODRIDGE LAKE CARP EXCLUSION DEVICE DESIGN by Princeton Hydro

The carp screen was specifically designed to be easy to operate and maintain, minimizing clogging and facilitating easy cleaning from the downstream side of the screen during a range of flows. The operation and maintenance plan also consists of inspections every three months and precipitation-based inspections conducted by the WLPOA staff.

Overall, the use of grass carp will help Woodridge Lake manage aquatic weed growth in a natural way and maintain a healthy and vibrant lake environment for years to come.

To learn more about Rowledge Pond Aquaculture, the oldest private fish hatchery in Connecticut, go here: rowledgepond.com. For more information about Princeton Hydro’s lake management services, go here: bit.ly/pondlake.