We’re committed to improving our ecosystems, quality of life, and communities for the better.
Our passion and commitment to the integration of innovative science and engineering drive us to exceed on behalf of every client.
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We are able to bring your project from its inception, through the planning and inventory phases, to project design and beyond. [parent] => 0 [count] => 21 [filter] => raw [term_order] => 3 ) [queried_object_id] => 1263 [request] => SELECT SQL_CALC_FOUND_ROWS ph_posts.ID FROM ph_posts LEFT JOIN ph_term_relationships ON (ph_posts.ID = ph_term_relationships.object_id) WHERE 1=1 AND ( ph_term_relationships.term_taxonomy_id IN (1270,1446,1454,1263,1447,1448,1449,1450,1451,1453,1455,1456) ) AND ((ph_posts.post_type = 'project' AND (ph_posts.post_status = 'publish' OR ph_posts.post_status = 'acf-disabled'))) GROUP BY ph_posts.ID ORDER BY ph_posts.menu_order, ph_posts.post_date DESC LIMIT 0, 10 [posts] => Array ( [0] => WP_Post Object ( [ID] => 17622 [post_author] => 1 [post_date] => 2025-06-03 11:47:38 [post_date_gmt] => 2025-06-03 11:47:38 [post_content] => Princeton Hydro was part of a two-firm team tasked with the completion of Phase II detail scour analyses for the New Jersey Turnpike Authority (NJTA), a major state-wide transportation authority. Princeton Hydro was specifically tasked with the completion of scour analyses for 13 individual major highway bridges. These bridges were distributed throughout the state and included structures in both the coastal plain and piedmont physiographic provinces. The road crossings at the focus of the study range from single lane exit ramps to five-lane single direction major highways. The average daily traffic load of combined 13 road crossings which were studied is 1.3 million vehicles per day. The detailed Phase II studies were conducted on structures which were previously identified during separate Phase I scour investigations and Biennial Bridge Inspection Reports. Inspections and investigations ultimately either confirmed the existing Federal Highway Authority Structure Inventory and Appraisal of the Nation’s Bridges (SI&A) codes including Items 61 (Channel and Channel Protection), Item 71 (Waterway Adequacy) and Item 113 (Scour Critical Bridges). Princeton Hydro provided a wide range of services as it related to the scour assessments. These services included field inspection service planning and logistics as well and watercraft access to bridge structures. In-field engineering inspections of bridge structures with a focus on scour were also completed for the 13 structures. These inspections included the collection of photographs of the bridge and surrounding channel conditions as well as the collection of representative soil samples. The soil samples were then delivered to our in-house soil laboratory, which is accredited under the American Association of State Highway and Transportation Officials (AASHTO) Accreditation Program (AAP), for analysis with the results of the soil analyses being applied in the scour analysis hydraulic calculations. Our engineering services included a detailed review of previous documentation for each bridge including original as-built drawing, previous inspection reports, and other National Bridge Inspection Standards (NBIS) reporting. The Phase II detailed scour analysis also included a hydrologic analysis for each road crossing with consequent hydraulic modeling of the bridge structure and stream channel being performed in HEC-RAS. Results from HEC-RAS were then used to conduct additional scour analysis in the Federal Highway Administration Hydraulic Toolbox. [post_title] => New Jersey Turnpike Authority Phase II Detail Scour Analysis [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => new-jersey-turnpike-authority-phase-ii-detail-scour-analysis [to_ping] => [pinged] => [post_modified] => 2025-06-03 11:47:38 [post_modified_gmt] => 2025-06-03 11:47:38 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=17622 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [1] => WP_Post Object ( [ID] => 17513 [post_author] => 1 [post_date] => 2025-05-14 15:51:00 [post_date_gmt] => 2025-05-14 15:51:00 [post_content] => Princeton Hydro was contracted by the American Littoral Society to complete design plans, permits and construction services for multiple water quality improvement projects conducted within Ocean County Park. The restoration and wetland pocket creation portion of the project is specific to work conducted during the summer of 2017 adjacent to Duck Pond, the second of three interconnected ponds located within the park. The overall purpose of the Duck Pond project was to reduce the non-point source loading of nitrogen and phosphorous. The reduction of nitrogen and phosphorus loading is a key element of the satisfying the Metedeconk River TMDL and addressing the causes for the eutrophication of Barnegat Bay. Along 140 feet of shoreline an existing bulkhead running along the entire perimeter of Duck Pond was removed. It was graded back in a way to create two small wetland pockets designed to receive spill over from the pond during moderate to large storm events as well as treat existing runoff from the park during smaller storm events that would otherwise discharge directly into the pond. These wetland pockets were also graded to create non-uniform microtopography for increased ecological benefit. The plant palette chosen strikes a balance between aesthetic design and water quality improvement. Princeton Hydro worked collaboratively with NJDEP to reduce the permitting burden on our project partners. Due to the intent of the project to improve water quality, we presented an alternative permitting strategy agreed upon by NJDEP, which allowed the permitting of the project via the FHA Control Act Rules. This approach removed the need for CAFRA permitting and reduced permit preparation costs, review time, and fees, ultimately resulting in excess funding being directed towards implementation. Following the project, in-stream in-situ and discrete water quality monitoring was conducted for one year in order to assess the effectiveness of the BMPs. The combined green infrastructure and living shoreline elements of this project set the stage for a much needed effort to reduce NPS loading and address waterfowl-related pathogen impacts to Ocean County Park’s lakes and the Metedeconk River. It heightened public awareness of NPS pollution and the benefits of green infrastructure. The project serves as a model for proper stormwater management and living shoreline creation throughout both the Metedeconk River and Barnegat Bay Watersheds. [post_title] => Ocean County Park Shoreline Restoration and Wetland Pocket Creation [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => ocean-county-park-shoreline-restoration-and-wetland-pocket-creation [to_ping] => [pinged] => [post_modified] => 2025-05-14 15:52:42 [post_modified_gmt] => 2025-05-14 15:52:42 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=17513 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [2] => WP_Post Object ( [ID] => 16980 [post_author] => 1 [post_date] => 2025-01-30 15:01:20 [post_date_gmt] => 2025-01-30 15:01:20 [post_content] => Liberty State Park is located on the west bank of Upper New York Bay and is one of the most visited state parks in the nation with over 5.1 million visitors in 2018. Princeton Hydro was contracted to design a resilient coastal ecosystem within 235 acres of this highly urbanized setting that provides both ecological and social benefits. This includes the restoration of over 80 acres of tidal and non-tidal wetlands and creation of several thousands of feet of intertidal shoreline and shallow water habitat hydrologically connected to the Upper New York Bay. Historically, the site contained intertidal mudflats and shallow water habitat, which were filled and developed as a railroad yard. Once constructed, this project will expand public access, improve water quality, restore native plant communities, and improve coastal resiliency for urban communities that are vulnerable to storm events. The site design includes a trail network for the park interior that will provide access to the newly established habitat zones and views of the Statue of Liberty and New York City skyline. This trail network will enhance pedestrian connectivity between the existing portion of Liberty State Park, Liberty Science Center, Jersey City, and local public transit hubs. To inform the design development, our team conducted design charrettes with various stakeholders and a myriad of monitoring tasks focused on site characterization including a wetland delineation; bio-benchmarking surveys of the tidal marsh vegetation communities; topographic, bathymetric, and utility surveys; and geotechnical sampling such as SPT borings and test pits. Field data and observations were incorporated into various analyses to support the engineering design including a 2D Hydrologic and Hydraulic model and wave analysis, and a detailed Sea Level Rise Analysis to inform the design of various project elements to accommodate sea level rise projections through 2070. The tidal channel geometry, culvert width, and tidal marsh were designed to address increased flows and water surface elevations. Groundwater levels and flow direction were also characterized through the installation of monitoring wells and continuous measurements of the groundwater level using piezometers. To support the design process, the team developed interim construction cost estimates for various design milestones and coordinated and advanced the local, state, and federal permit process and applications. As part of NJDEP’s public outreach campaign, our team participated in an open house interacting directly with members of the public. We produced a 4-minute video simulating the expected visitor experience using detailed engineering design renderings. When completed, this will be one of the largest ecosystem habitat restoration projects in New Jersey. Click below to watch the video now: [embed]https://youtu.be/XbzQ08o7b5Y[/embed] [post_title] => Liberty State Park Ecosystem Restoration [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => liberty-state-park-ecosystem-restoration [to_ping] => [pinged] => [post_modified] => 2025-01-30 16:01:12 [post_modified_gmt] => 2025-01-30 16:01:12 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=16980 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [3] => WP_Post Object ( [ID] => 15996 [post_author] => 1 [post_date] => 2024-12-02 15:28:32 [post_date_gmt] => 2024-12-02 15:28:32 [post_content] => The Spring Creek (North) Ecosystem Restoration Project is located in the boroughs of Brooklyn and Queens, New York. In the early 1900’s, the salt marsh community of Spring Creek was part of the extensive coastal wetland community of Jamaica Bay, known for the abundance and diversity of its shellfish as well as its ecological importance as a nursery and feeding ground for countless species of birds and fish. The intertidal salt marsh and uplands have since been degraded by historic placement of dredged spoils and municipal waste, the construction of a sanitary sewer trunk line, ditching of the marsh, and urbanization of the watershed. When completed, the project will restore approximately 43.2 acres of degraded habitat to 0.7 acres of low marsh, 12.9 acres of transitional and high marsh, 5.2 acres of scrub shrub wetland and 24.4 acres of maritime upland in an overall project footprint of 67 acres. Primary construction activities will include excavating and re-contouring uplands to intertidal elevations, thin layer placement of sand on the marsh platform to restore areas of degraded tidal wetland, removing invasive plant species, and replanting with native plant species. The overall project purpose is to improve the environmental quality (water, diversity, and wildlife habitat) of Spring Creek and its associated salt marshes as part of the overall Jamaica Bay Ecosystem. [gallery link="none" ids="15997,15998,16000"] Princeton Hydro was contracted by the US Army Corps of Engineers, New York District to lead the design and engineering. To inform the design development, a variety of site-specific data was collected including topographic, bathymetric, utility and tree surveys. Wetland delineation and vegetation characterization were performed, along with a bio-benchmark survey to establish marsh habitat boundaries; hydrodynamic data; and geotechnical borings. The data collected was analyzed and incorporated into the design, including a sea level change analysis; slope stability analysis; development of a hydrologic model and an unsteady 1-D hydraulic model; stormwater design; and wetland restoration design. A concept design was developed in coordination with the US Army Corps of Engineers and New York City Parks, and the design was advanced via the preparation of 30%, 60%, 90%, and 100% design plans and technical specifications. Additionally, the required local, state, and federal permits were obtained, and a detailed construction cost estimate was developed. [post_title] => Spring Creek North Ecosystem Restoration Project [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => spring-creek-north-ecosystem-restoration-project [to_ping] => [pinged] => [post_modified] => 2024-12-02 15:29:53 [post_modified_gmt] => 2024-12-02 15:29:53 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=15996 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [4] => WP_Post Object ( [ID] => 15994 [post_author] => 1 [post_date] => 2024-12-02 14:40:59 [post_date_gmt] => 2024-12-02 14:40:59 [post_content] => Tanglwood Lake, located in Pike County, PA, is an impoundment created by Tanglwood Lake Dam, which is owned and maintained by the Tanglwood Lakes Community Association, Inc. (TLCA). Classified as a High-Quality, Cold-Water Fishery (HQ-CWF) for water quality protection, it accepts flow from Lake Wallenpaupack via Kleinhans Creek. The drainage area to the lake is approximately 0.6 square miles (384 Acres). The lake itself is approximately 26.0 acres. Princeton Hydro has been contracted to conduct lake management services for TLCA since 2016 and was contracted to perform consulting and engineering services for design, permitting, bidding, construction administration, and construction oversight for the partial sediment removal from Tanglwood Lake through hydraulic dredging and onsite disposal. Princeton Hydro conducted a bathymetric survey and performed sediment sampling to determine the volume and consistency of the sediment as well as the feasibility of onsite dewatering. Building on this previous work, wetland delineation and a site survey were conducted to collect data to inform the engineering design, regulatory compliance, contractor solicitation, and construction. Princeton Hydro’s regulatory experts prepared all applicable state and federal permits, including PADEP Dam Safety; Soil Erosion and Sediment Control Plan Certification; and NPDES Stormwater Permit for the sediment removal; dewatering; and disposal on the adjacent lot. [gallery columns="2" link="none" ids="15990,15991"] The engineering design for sediment removal and dewatering was completed, along with the engineering design for the disposal area of the dewatered dredged material. The dredging occurred over multiple events, with approximately 2,000 cubic yards of sediment and organics removed from the eastern portion of the lake. This sediment was dewatered using geotubes placed on a gravel bed. Once dewatered and all approvals were obtained, the sediment was relocated to the adjacent lot to create a gentle slope off the roadway and to make the site more park-like for the community. [post_title] => Tanglwood Lake Maintenance Dredging [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => tanglwood-lake-maintenance-dredging [to_ping] => [pinged] => [post_modified] => 2024-12-02 14:44:43 [post_modified_gmt] => 2024-12-02 14:44:43 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=15994 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [5] => WP_Post Object ( [ID] => 15954 [post_author] => 1 [post_date] => 2024-11-08 19:07:55 [post_date_gmt] => 2024-11-08 19:07:55 [post_content] => The New Jersey Back Bay (NJBB) Coastal Storm Risk Management (CSRM) feasibility study is focused on the approximately 100 miles of interconnected tidal water bodies and coastal lakes located landward of the New Jersey Ocean coastline from the Manasquan Inlet to the Cape May Inlet. These areas were subject to recent flooding, storm surge, and damages as a result of Hurricane Sandy and other storm events. As part of this study, the United States Army Corps of Engineers (USACE) Philadelphia District developed a preliminary alignment for a storm surge barrier located in Great Egg Harbor Inlet in Atlantic and Cape May Counties. This preliminary barrier would serve as the representative design for all planned storm surge barriers as part of the project. Through an existing contract with USACE Philadelphia District, Princeton Hydro was tasked with performing a water-based subsurface exploration along the preliminary barrier alignment. This exploration consisted of nine (9) Cone Penetration Tests (CPTs) with continuous pore pressure measurements to a maximum depth of 150 ft below the mudline or until refusal was encountered. To perform the testing, Princeton Hydro required subcontracted services provided by Northstar Marine Services, Inc., ConeTec, and Boring Brothers, Inc. CPT soundings were performed from Northstar Marine Services’ 70 ft Lift Boat, the Vision. A rubber track mounted, low- clearance drill rig was provided by Boring Brothers, Inc. to socket casings into the mudline by way of the moon pool of the barge. Once casings were set, ConeTec utilized their Direct Push Overwater Ramset to continuously advance the CPT soundings to the termination depth. During the entire operation, Princeton Hydro provided continuous oversight as well as regular Health and Safety Inspections. The information collected during the investigation was provided to USACE for use in the design of the storm surge barrier. [gallery columns="2" link="none" size="medium" ids="15956,15955"] [post_title] => NJ Back Bays Coastal Storm Risk Management Feasibility Study & Subsurface Exploration [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => nj-back-bays-coastal-storm-risk-management-feasibility-study-subsurface-exploration [to_ping] => [pinged] => [post_modified] => 2024-11-08 19:08:12 [post_modified_gmt] => 2024-11-08 19:08:12 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=15954 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [6] => WP_Post Object ( [ID] => 15951 [post_author] => 1 [post_date] => 2024-11-07 18:54:42 [post_date_gmt] => 2024-11-07 18:54:42 [post_content] => The Martin Dam was constructed on an active farm in 1961 as part of USDA’s sustainable farms pond construction initiative. Martin Dam’s robust 4,000 cubic yards of placed dam material resulted in the impoundment of only 3.5 acres of surface water. Several years ago, during the removal of a beaver dam that was obstructing the dam outlet, the riser structure was inadvertently destroyed, and a large part of the earthen dam collapsed. Due to the damage, the dam was put under an enforcement action from the Maryland Department of the Environment (MDE) Dam Safety Program. Site investigations showed an outlet culvert in total disrepair and severe erosion of the dam and downstream areas. Fearing the risk to property and life from a catastrophic dam failure, GreenTrust Alliance, in partnership with Princeton Hydro, were enlisted to design, develop, and enact an emergency dam breach. The earthen dam was approximately 20 feet in height and 490 feet in length, with an impoundment of approximately 3.48 acres. The contributing drainage area was approximately 0.25 square miles (160 acres) of low density residential land use and the primary inflowing channel, Overshot Branch, was intermittent or ephemeral. The assessment and design involved probing within the impoundment, which revealed water depths averaging 4.7 feet, with a maximum of 7.5 feet, and impounded sediment depths averaging 1.0 foot, with a maximum of 3.0 feet. Princeton Hydro prepared a 35% design plan for the earthen dam removal, and this plan was subsequently approved by MDE Dam Safety with an emergency permit, forgoing the typical months-long design and review process. The dam breach was implemented in late 2018. After the dam breach, Princeton Hydro completed a hydrologic and hydraulic assessment. Pre- and post-breach conditions were modeled to determine the potential increase in flood elevations to downstream properties. In addition, a dam failure was also modeled to assess the potential risks should the dam have failed. In comparing the pre-and post-breach scenarios, 100-year flood elevations increased between 0.01 and 0.29 feet for approximately 1 mile downstream of the pond. The floodplain valley for this stream was relatively narrow which means any increases in discharge translated to larger increases on peak flood elevations compared to the total width of the floodplain. However, the narrow floodplain also acted a barrier, ensuring that flooding was mostly contained to the area around the stream itself. No additional structures were inundated as a result of the breach. Princeton Hydro, along with GreenVest and Green Trust Alliance, developed a design that enhanced in-stream habitat of the downstream reach, and allowed for passive wetland conversion and restoration of the former impoundment. [post_title] => Martin Farm Pond Emergency Dam Breach & Dam Removal [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => martin-farm-pond-emergency-dam-breach-dam-removal [to_ping] => [pinged] => [post_modified] => 2024-11-08 19:01:34 [post_modified_gmt] => 2024-11-08 19:01:34 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=15951 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [7] => WP_Post Object ( [ID] => 15857 [post_author] => 1 [post_date] => 2024-10-17 19:00:08 [post_date_gmt] => 2024-10-17 19:00:08 [post_content] => Princeton Hydro and BRS, Inc. were contracted by the Cities of Trenton and Salem to perform climate change-related hazard vulnerability assessments to inform municipal resilience action plans. The work was completed as part of the Resilient NJ Program, an assistance program run by the NJDEP Bureau of Climate Resilience Planning. The program supports local and regional climate resilience planning by bringing together planners, engineers, designers, and other experts to address flood- and climate-related hazards. The Cities of Trenton and Salem, like many across the region, already experience climate related hazards such as extreme heat and flooding which disrupts traffic patterns, impacts infrastructure, damages property, and puts lives at risk. These climate-related hazards are expected to worsen over the next century and beyond due to climate change. In order to prepare for and adapt to climate-related hazards, our team worked to map extreme heat and flooding hazards across these cities under both current climate conditions and future projections. We then assessed the geographic distribution of these hazards to identify at-risk populations and city resources, such as critical infrastructure, community assets, cultural and historic resources, and land developments. These assessments will be used to develop resilience action plans, which will guide future climate hazard policies, planning, and projects in Trenton and Salem. [caption id="attachment_15855" align="aligncenter" width="1596"] Salem[/caption] [caption id="attachment_15856" align="aligncenter" width="1585"] Trenton[/caption] A key component of our climate hazard vulnerability assessments was to not only provide information needed for planning and decision-making, but to also provide information to the general public. Princeton Hydro and BRS facilitated several public information sessions. The Princeton Hydro-BRS Team provided a primer on climate hazards and presented the vulnerability assessment findings along with a Q&A session. This process invited public feedback and maximized public participation. [post_title] => Resilient NJ - Trenton and Salem [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => resilient-nj-trenton-and-salem [to_ping] => [pinged] => [post_modified] => 2024-10-17 19:00:08 [post_modified_gmt] => 2024-10-17 19:00:08 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=15857 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [8] => WP_Post Object ( [ID] => 15746 [post_author] => 1 [post_date] => 2024-09-18 10:26:31 [post_date_gmt] => 2024-09-18 10:26:31 [post_content] => The objectives of the Upper Weadly Stormwater Improvement Projects are to address flooding within the Trout Creek watershed of Tredyffrin Township located in Chester County, Pennsylvania. The 70-acre watershed contains a suburban development consisting mostly of 1/2-acre resident lots. The watershed was developed prior to modern stormwater management requirements. As a result, the stormwater management infrastructure in place is undersized and in poor condition. The watershed suffers from chronic flooding that is a threat to the quality of life for the residents. [gallery columns="2" link="none" size="medium" ids="15748,15749"] Princeton Hydro developed a hydrologic model of the entire 70-acre watershed and its existing stormwater system, which was used to find critical points in the existing stormwater system that are triggering localized flooding events. The model was built from both survey data collected in the field and as-builts provided by the Township. Princeton Hydro also was tasked with finding opportunities to use grey and green infrastructure to minimize flooding events. The size of the identified and proposed infrastructure was determined by the hydrologic model. The Township officials and Princeton Hydro held two public meetings to engage residents of the neighborhood. The purpose of the first meeting was to introduce the project to the residents and gather information about localized flooding. The residents shared stories and information from flooding events they had witnessed over the years. The second meeting was to share the proposed improvements for the neighborhood and to garner support from the residents for the proposed changes. The project is still in the design phase and is scheduled to go out to bid in September 2024. [post_title] => Upper Weadley Stormwater Improvement Projects [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => upper-weadley-stormwater-improvement-projects [to_ping] => [pinged] => [post_modified] => 2024-09-18 10:26:31 [post_modified_gmt] => 2024-09-18 10:26:31 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=15746 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [9] => WP_Post Object ( [ID] => 15745 [post_author] => 1 [post_date] => 2024-09-18 10:08:48 [post_date_gmt] => 2024-09-18 10:08:48 [post_content] => Princeton Hydro was on the team to study the Bronx River Double Dam for New York City Parks (the dam owner). The project goal was to present an economically, environmentally, and socially sustainable long-term fish-passage solution for the Bronx River Double Dam. [gallery link="none" size="medium" ids="15744,15743,15742"] The culmination of the project was a fish passage Alternatives Analysis for the dam site, where the cost and benefits of various long-term solutions for the project site were assessed, including dam removal and an engineered fishway. To inform the Alternatives Analysis, Princeton Hydro first studied the feasibility of the removal of the Bronx River Double Dam. To inform the dam removal feasibility study and a conceptual dam removal design, Princeton Hydro supplemented data from a previous technical fishway design with data collected from additional field investigations. Princeton Hydro led the field collection effort, including sediment sampling, sediment probing, and a bathymetric survey to shed light on the impounded sediment concerns. Field investigations also included an investigation on the infrastructure, an updated topographic survey, and a seismic refraction survey to understand the potential for underlying bedrock to inform a conceptual design for dam removal. Based on the data reviewed, Princeton Hydro concluded that dam removal is feasible and that its removal would 1) Restore the Bronx River to its historical flowpath, 2) Likely restore transparent fish passage at the site, and 3) Not impact infrastructure. In comparing the dam removal alternative to the engineering fishway, the dam removal would provide a greater ecological benefit, while also reducing long term liabilities related to dam failure and costs associated with dam maintenance and inspection. Despite uncertainty associated with the dam removal alternative at this stage in the concept design, it is expected the upfront construction cost of the dam removal would be higher than the engineering fishway alternative. The feasibility study and alternatives analysis set the stage for the US Army Corps of Engineers to further study fish passage at the Bronx River Double Dam. [post_title] => Bronx River Double Dam Fish Passage Assessment [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => bronx-river-double-dam-fish-passage-assessment [to_ping] => [pinged] => [post_modified] => 2024-09-18 10:09:22 [post_modified_gmt] => 2024-09-18 10:09:22 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=15745 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) ) [post_count] => 10 [current_post] => -1 [before_loop] => 1 [in_the_loop] => [post] => WP_Post Object ( [ID] => 17622 [post_author] => 1 [post_date] => 2025-06-03 11:47:38 [post_date_gmt] => 2025-06-03 11:47:38 [post_content] => Princeton Hydro was part of a two-firm team tasked with the completion of Phase II detail scour analyses for the New Jersey Turnpike Authority (NJTA), a major state-wide transportation authority. Princeton Hydro was specifically tasked with the completion of scour analyses for 13 individual major highway bridges. These bridges were distributed throughout the state and included structures in both the coastal plain and piedmont physiographic provinces. The road crossings at the focus of the study range from single lane exit ramps to five-lane single direction major highways. The average daily traffic load of combined 13 road crossings which were studied is 1.3 million vehicles per day. The detailed Phase II studies were conducted on structures which were previously identified during separate Phase I scour investigations and Biennial Bridge Inspection Reports. Inspections and investigations ultimately either confirmed the existing Federal Highway Authority Structure Inventory and Appraisal of the Nation’s Bridges (SI&A) codes including Items 61 (Channel and Channel Protection), Item 71 (Waterway Adequacy) and Item 113 (Scour Critical Bridges). Princeton Hydro provided a wide range of services as it related to the scour assessments. These services included field inspection service planning and logistics as well and watercraft access to bridge structures. In-field engineering inspections of bridge structures with a focus on scour were also completed for the 13 structures. These inspections included the collection of photographs of the bridge and surrounding channel conditions as well as the collection of representative soil samples. The soil samples were then delivered to our in-house soil laboratory, which is accredited under the American Association of State Highway and Transportation Officials (AASHTO) Accreditation Program (AAP), for analysis with the results of the soil analyses being applied in the scour analysis hydraulic calculations. Our engineering services included a detailed review of previous documentation for each bridge including original as-built drawing, previous inspection reports, and other National Bridge Inspection Standards (NBIS) reporting. The Phase II detailed scour analysis also included a hydrologic analysis for each road crossing with consequent hydraulic modeling of the bridge structure and stream channel being performed in HEC-RAS. Results from HEC-RAS were then used to conduct additional scour analysis in the Federal Highway Administration Hydraulic Toolbox. 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Princeton Hydro was part of a two-firm team tasked with the completion of Phase II detail scour analyses for the New Jersey Turnpike Authority (NJTA), a major state-wide transportation authority. Princeton Hydro was specifically tasked with the completion of scour analyses for 13 individual major highway bridges. These bridges were distributed throughout the state and included structures in both the coastal plain and piedmont physiographic provinces. The road crossings at the focus of the study range from single lane exit ramps to five-lane single direction major highways. The average daily traffic load of combined 13 road crossings which were studied is 1.3 million vehicles per day.
The detailed Phase II studies were conducted on structures which were previously identified during separate Phase I scour investigations and Biennial Bridge Inspection Reports. Inspections and investigations ultimately either confirmed the existing Federal Highway Authority Structure Inventory and Appraisal of the Nation’s Bridges (SI&A) codes including Items 61 (Channel and Channel Protection), Item 71 (Waterway Adequacy) and Item 113 (Scour Critical Bridges).
Princeton Hydro provided a wide range of services as it related to the scour assessments. These services included field inspection service planning and logistics as well and watercraft access to bridge structures. In-field engineering inspections of bridge structures with a focus on scour were also completed for the 13 structures. These inspections included the collection of photographs of the bridge and surrounding channel conditions as well as the collection of representative soil samples.
The soil samples were then delivered to our in-house soil laboratory, which is accredited under the American Association of State Highway and Transportation Officials (AASHTO) Accreditation Program (AAP), for analysis with the results of the soil analyses being applied in the scour analysis hydraulic calculations.
Our engineering services included a detailed review of previous documentation for each bridge including original as-built drawing, previous inspection reports, and other National Bridge Inspection Standards (NBIS) reporting. The Phase II detailed scour analysis also included a hydrologic analysis for each road crossing with consequent hydraulic modeling of the bridge structure and stream channel being performed in HEC-RAS. Results from HEC-RAS were then used to conduct additional scour analysis in the Federal Highway Administration Hydraulic Toolbox.
Princeton Hydro was contracted by the American Littoral Society to complete design plans, permits and construction services for multiple water quality improvement projects conducted within Ocean County Park. The restoration and wetland pocket creation portion of the project is specific to work conducted during the summer of 2017 adjacent to Duck Pond, the second of three interconnected ponds located within the park. The overall purpose of the Duck Pond project was to reduce the non-point source loading of nitrogen and phosphorous. The reduction of nitrogen and phosphorus loading is a key element of the satisfying the Metedeconk River TMDL and addressing the causes for the eutrophication of Barnegat Bay.
Along 140 feet of shoreline an existing bulkhead running along the entire perimeter of Duck Pond was removed. It was graded back in a way to create two small wetland pockets designed to receive spill over from the pond during moderate to large storm events as well as treat existing runoff from the park during smaller storm events that would otherwise discharge directly into the pond. These wetland pockets were also graded to create non-uniform microtopography for increased ecological benefit. The plant palette chosen strikes a balance between aesthetic design and water quality improvement. Princeton Hydro worked collaboratively with NJDEP to reduce the permitting burden on our project partners. Due to the intent of the project to improve water quality, we presented an alternative permitting strategy agreed upon by NJDEP, which allowed the permitting of the project via the FHA Control Act Rules. This approach removed the need for CAFRA permitting and reduced permit preparation costs, review time, and fees, ultimately resulting in excess funding being directed towards implementation.
Following the project, in-stream in-situ and discrete water quality monitoring was conducted for one year in order to assess the effectiveness of the BMPs. The combined green infrastructure and living shoreline elements of this project set the stage for a much needed effort to reduce NPS loading and address waterfowl-related pathogen impacts to Ocean County Park’s lakes and the Metedeconk River. It heightened public awareness of NPS pollution and the benefits of green infrastructure. The project serves as a model for proper stormwater management and living shoreline creation throughout both the Metedeconk River and Barnegat Bay Watersheds.
Liberty State Park is located on the west bank of Upper New York Bay and is one of the most visited state parks in the nation with over 5.1 million visitors in 2018. Princeton Hydro was contracted to design a resilient coastal ecosystem within 235 acres of this highly urbanized setting that provides both ecological and social benefits. This includes the restoration of over 80 acres of tidal and non-tidal wetlands and creation of several thousands of feet of intertidal shoreline and shallow water habitat hydrologically connected to the Upper New York Bay.
Historically, the site contained intertidal mudflats and shallow water habitat, which were filled and developed as a railroad yard. Once constructed, this project will expand public access, improve water quality, restore native plant communities, and improve coastal resiliency for urban communities that are vulnerable to storm events. The site design includes a trail network for the park interior that will provide access to the newly established habitat zones and views of the Statue of Liberty and New York City skyline. This trail network will enhance pedestrian connectivity between the existing portion of Liberty State Park, Liberty Science Center, Jersey City, and local public transit hubs.
To inform the design development, our team conducted design charrettes with various stakeholders and a myriad of monitoring tasks focused on site characterization including a wetland delineation; bio-benchmarking surveys of the tidal marsh vegetation communities; topographic, bathymetric, and utility surveys; and geotechnical sampling such as SPT borings and test pits. Field data and observations were incorporated into various analyses to support the engineering design including a 2D Hydrologic and Hydraulic model and wave analysis, and a detailed Sea Level Rise Analysis to inform the design of various project elements to accommodate sea level rise projections through 2070. The tidal channel geometry, culvert width, and tidal marsh were designed to address increased flows and water surface elevations. Groundwater levels and flow direction were also characterized through the installation of monitoring wells and continuous measurements of the groundwater level using piezometers.
To support the design process, the team developed interim construction cost estimates for various design milestones and coordinated and advanced the local, state, and federal permit process and applications. As part of NJDEP’s public outreach campaign, our team participated in an open house interacting directly with members of the public. We produced a 4-minute video simulating the expected visitor experience using detailed engineering design renderings. When completed, this will be one of the largest ecosystem habitat restoration projects in New Jersey. Click below to watch the video now:
The Spring Creek (North) Ecosystem Restoration Project is located in the boroughs of Brooklyn and Queens, New York. In the early 1900’s, the salt marsh community of Spring Creek was part of the extensive coastal wetland community of Jamaica Bay, known for the abundance and diversity of its shellfish as well as its ecological importance as a nursery and feeding ground for countless species of birds and fish. The intertidal salt marsh and uplands have since been degraded by historic placement of dredged spoils and municipal waste, the construction of a sanitary sewer trunk line, ditching of the marsh, and urbanization of the watershed.
When completed, the project will restore approximately 43.2 acres of degraded habitat to 0.7 acres of low marsh, 12.9 acres of transitional and high marsh, 5.2 acres of scrub shrub wetland and 24.4 acres of maritime upland in an overall project footprint of 67 acres. Primary construction activities will include excavating and re-contouring uplands to intertidal elevations, thin layer placement of sand on the marsh platform to restore areas of degraded tidal wetland, removing invasive plant species, and replanting with native plant species. The overall project purpose is to improve the environmental quality (water, diversity, and wildlife habitat) of Spring Creek and its associated salt marshes as part of the overall Jamaica Bay Ecosystem.
Princeton Hydro was contracted by the US Army Corps of Engineers, New York District to lead the design and engineering. To inform the design development, a variety of site-specific data was collected including topographic, bathymetric, utility and tree surveys. Wetland delineation and vegetation characterization were performed, along with a bio-benchmark survey to establish marsh habitat boundaries; hydrodynamic data; and geotechnical borings. The data collected was analyzed and incorporated into the design, including a sea level change analysis; slope stability analysis; development of a hydrologic model and an unsteady 1-D hydraulic model; stormwater design; and wetland restoration design.
A concept design was developed in coordination with the US Army Corps of Engineers and New York City Parks, and the design was advanced via the preparation of 30%, 60%, 90%, and 100% design plans and technical specifications. Additionally, the required local, state, and federal permits were obtained, and a detailed construction cost estimate was developed.
Tanglwood Lake, located in Pike County, PA, is an impoundment created by Tanglwood Lake Dam, which is owned and maintained by the Tanglwood Lakes Community Association, Inc. (TLCA). Classified as a High-Quality, Cold-Water Fishery (HQ-CWF) for water quality protection, it accepts flow from Lake Wallenpaupack via Kleinhans Creek. The drainage area to the lake is approximately 0.6 square miles (384 Acres). The lake itself is approximately 26.0 acres.
Princeton Hydro has been contracted to conduct lake management services for TLCA since 2016 and was contracted to perform consulting and engineering services for design, permitting, bidding, construction administration, and construction oversight for the partial sediment removal from Tanglwood Lake through hydraulic dredging and onsite disposal. Princeton Hydro conducted a bathymetric survey and performed sediment sampling to determine the volume and consistency of the sediment as well as the feasibility of onsite dewatering. Building on this previous work, wetland delineation and a site survey were conducted to collect data to inform the engineering design, regulatory compliance, contractor solicitation, and construction. Princeton Hydro’s regulatory experts prepared all applicable state and federal permits, including PADEP Dam Safety; Soil Erosion and Sediment Control Plan Certification; and NPDES Stormwater Permit for the sediment removal; dewatering; and disposal on the adjacent lot.
The engineering design for sediment removal and dewatering was completed, along with the engineering design for the disposal area of the dewatered dredged material. The dredging occurred over multiple events, with approximately 2,000 cubic yards of sediment and organics removed from the eastern portion of the lake. This sediment was dewatered using geotubes placed on a gravel bed. Once dewatered and all approvals were obtained, the sediment was relocated to the adjacent lot to create a gentle slope off the roadway and to make the site more park-like for the community.
The New Jersey Back Bay (NJBB) Coastal Storm Risk Management (CSRM) feasibility study is focused on the approximately 100 miles of interconnected tidal water bodies and coastal lakes located landward of the New Jersey Ocean coastline from the Manasquan Inlet to the Cape May Inlet. These areas were subject to recent flooding, storm surge, and damages as a result of Hurricane Sandy and other storm events. As part of this study, the United States Army Corps of Engineers (USACE) Philadelphia District developed a preliminary alignment for a storm surge barrier located in Great Egg Harbor Inlet in Atlantic and Cape May Counties. This preliminary barrier would serve as the representative design for all planned storm surge barriers as part of the project.
Through an existing contract with USACE Philadelphia District, Princeton Hydro was tasked with performing a water-based subsurface exploration along the preliminary barrier alignment. This exploration consisted of nine (9) Cone Penetration Tests (CPTs) with continuous pore pressure measurements to a maximum depth of 150 ft below the mudline or until refusal was encountered. To perform the testing, Princeton Hydro required subcontracted services provided by Northstar Marine Services, Inc., ConeTec, and Boring Brothers, Inc.
CPT soundings were performed from Northstar Marine Services’ 70 ft Lift Boat, the Vision. A rubber track mounted, low- clearance drill rig was provided by Boring Brothers, Inc. to socket casings into the mudline by way of the moon pool of the barge. Once casings were set, ConeTec utilized their Direct Push Overwater Ramset to continuously advance the CPT soundings to the termination depth. During the entire operation, Princeton Hydro provided continuous oversight as well as regular Health and Safety Inspections. The information collected during the investigation was provided to USACE for use in the design of the storm surge barrier.
The Martin Dam was constructed on an active farm in 1961 as part of USDA’s sustainable farms pond construction initiative. Martin Dam’s robust 4,000 cubic yards of placed dam material resulted in the impoundment of only 3.5 acres of surface water. Several years ago, during the removal of a beaver dam that was obstructing the dam outlet, the riser structure was inadvertently destroyed, and a large part of the earthen dam collapsed. Due to the damage, the dam was put under an enforcement action from the Maryland Department of the Environment (MDE) Dam Safety Program. Site investigations showed an outlet culvert in total disrepair and severe erosion of the dam and downstream areas.
Fearing the risk to property and life from a catastrophic dam failure, GreenTrust Alliance, in partnership with Princeton Hydro, were enlisted to design, develop, and enact an emergency dam breach. The earthen dam was approximately 20 feet in height and 490 feet in length, with an impoundment of approximately 3.48 acres. The contributing drainage area was approximately 0.25 square miles (160 acres) of low density residential land use and the primary inflowing channel, Overshot Branch, was intermittent or ephemeral. The assessment and design involved probing within the impoundment, which revealed water depths averaging 4.7 feet, with a maximum of 7.5 feet, and impounded sediment depths averaging 1.0 foot, with a maximum of 3.0 feet.
Princeton Hydro prepared a 35% design plan for the earthen dam removal, and this plan was subsequently approved by MDE Dam Safety with an emergency permit, forgoing the typical months-long design and review process. The dam breach was implemented in late 2018.
After the dam breach, Princeton Hydro completed a hydrologic and hydraulic assessment. Pre- and post-breach conditions were modeled to determine the potential increase in flood elevations to downstream properties. In addition, a dam failure was also modeled to assess the potential risks should the dam have failed. In comparing the pre-and post-breach scenarios, 100-year flood elevations increased between 0.01 and 0.29 feet for approximately 1 mile downstream of the pond. The floodplain valley for this stream was relatively narrow which means any increases in discharge translated to larger increases on peak flood elevations compared to the total width of the floodplain. However, the narrow floodplain also acted a barrier, ensuring that flooding was mostly contained to the area around the stream itself. No additional structures were inundated as a result of the breach.
Princeton Hydro, along with GreenVest and Green Trust Alliance, developed a design that enhanced in-stream habitat of the downstream reach, and allowed for passive wetland conversion and restoration of the former impoundment.
Princeton Hydro and BRS, Inc. were contracted by the Cities of Trenton and Salem to perform climate change-related hazard vulnerability assessments to inform municipal resilience action plans.
The work was completed as part of the Resilient NJ Program, an assistance program run by the NJDEP Bureau of Climate Resilience Planning. The program supports local and regional climate resilience planning by bringing together planners, engineers, designers, and other experts to address flood- and climate-related hazards. The Cities of Trenton and Salem, like many across the region, already experience climate related hazards such as extreme heat and flooding which disrupts traffic patterns, impacts infrastructure, damages property, and puts lives at risk. These climate-related hazards are expected to worsen over the next century and beyond due to climate change.
In order to prepare for and adapt to climate-related hazards, our team worked to map extreme heat and flooding hazards across these cities under both current climate conditions and future projections. We then assessed the geographic distribution of these hazards to identify at-risk populations and city resources, such as critical infrastructure, community assets, cultural and historic resources, and land developments. These assessments will be used to develop resilience action plans, which will guide future climate hazard policies, planning, and projects in Trenton and Salem.
A key component of our climate hazard vulnerability assessments was to not only provide information needed for planning and decision-making, but to also provide information to the general public. Princeton Hydro and BRS facilitated several public information sessions. The Princeton Hydro-BRS Team provided a primer on climate hazards and presented the vulnerability assessment findings along with a Q&A session. This process invited public feedback and maximized public participation.
The objectives of the Upper Weadly Stormwater Improvement Projects are to address flooding within the Trout Creek watershed of Tredyffrin Township located in Chester County, Pennsylvania. The 70-acre watershed contains a suburban development consisting mostly of 1/2-acre resident lots. The watershed was developed prior to modern stormwater management requirements. As a result, the stormwater management infrastructure in place is undersized and in poor condition. The watershed suffers from chronic flooding that is a threat to the quality of life for the residents.
Princeton Hydro developed a hydrologic model of the entire 70-acre watershed and its existing stormwater system, which was used to find critical points in the existing stormwater system that are triggering localized flooding events. The model was built from both survey data collected in the field and as-builts provided by the Township. Princeton Hydro also was tasked with finding opportunities to use grey and green infrastructure to minimize flooding events. The size of the identified and proposed infrastructure was determined by the hydrologic model.
The Township officials and Princeton Hydro held two public meetings to engage residents of the neighborhood. The purpose of the first meeting was to introduce the project to the residents and gather information about localized flooding. The residents shared stories and information from flooding events they had witnessed over the years. The second meeting was to share the proposed improvements for the neighborhood and to garner support from the residents for the proposed changes.
The project is still in the design phase and is scheduled to go out to bid in September 2024.
Princeton Hydro was on the team to study the Bronx River Double Dam for New York City Parks (the dam owner). The project goal was to present an economically, environmentally, and socially sustainable long-term fish-passage solution for the Bronx River Double Dam.
The culmination of the project was a fish passage Alternatives Analysis for the dam site, where the cost and benefits of various long-term solutions for the project site were assessed, including dam removal and an engineered fishway. To inform the Alternatives Analysis, Princeton Hydro first studied the feasibility of the removal of the Bronx River Double Dam.
To inform the dam removal feasibility study and a conceptual dam removal design, Princeton Hydro supplemented data from a previous technical fishway design with data collected from additional field investigations. Princeton Hydro led the field collection effort, including sediment sampling, sediment probing, and a bathymetric survey to shed light on the impounded sediment concerns. Field investigations also included an investigation on the infrastructure, an updated topographic survey, and a seismic refraction survey to understand the potential for underlying bedrock to inform a conceptual design for dam removal.
Based on the data reviewed, Princeton Hydro concluded that dam removal is feasible and that its removal would 1) Restore the Bronx River to its historical flowpath, 2) Likely restore transparent fish passage at the site, and 3) Not impact infrastructure.
In comparing the dam removal alternative to the engineering fishway, the dam removal would provide a greater ecological benefit, while also reducing long term liabilities related to dam failure and costs associated with dam maintenance and inspection. Despite uncertainty associated with the dam removal alternative at this stage in the concept design, it is expected the upfront construction cost of the dam removal would be higher than the engineering fishway alternative.
The feasibility study and alternatives analysis set the stage for the US Army Corps of Engineers to further study fish passage at the Bronx River Double Dam.
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