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Vibracore samples were collected by the USACE Wilmington District vessel, Brandy Station, at existing and potential borrow areas located offshore near Cape May, Hereford to Townsends Inlet, Absecon Inlet, Long Beach Island, and Manasquan to Barnegat Inlet. Seventy-nine (79) total vibracore samples were collected, each extending approximately twenty (20) feet below the mudline at each location. Following the completion of the field investigation, the samples were collected directly from the Government vessel and delivered to Princeton Hydro’s AASHTO accredited and USACE validated soils laboratory for logging and materials testing. From the vibracores, a total of four-hundred and fifty (450) samples were selected for grain size analysis. A summary report was provided to USACE upon completion of the laboratory testing detailing the methodologies used for laboratory testing, results of the grain size analysis, detailed vibracore logs, and a summary of the soils observed in each of the retrieved vibracore samples. [post_title] => New Jersey Borrow Area Vibracores Subsurface Investigation [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => new-jersey-borrow-area-vibracores-subsurface-investigation [to_ping] => [pinged] => [post_modified] => 2025-12-08 21:44:59 [post_modified_gmt] => 2025-12-08 21:44:59 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=18815 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [1] => WP_Post Object ( [ID] => 18593 [post_author] => 1 [post_date] => 2025-10-11 13:50:05 [post_date_gmt] => 2025-10-11 13:50:05 [post_content] => Princeton Hydro has partnered with Wildlands Conservancy for over a decade on multiple dam removals in the Lehigh River Valley. Our firm designed and permitted the removal of eight consecutive barriers on Jordan Creek, including three consecutive low-head dams. We also designed and permitted two low-head dams on Little Lehigh Creek. Collectively, these dam removal projects reconnected miles of river, enhanced aquatic habitat, and improved adjacent parkland and recreational fishing in the economically-stressed, urban communities of Allentown, PA. Building upon the successes of the barrier removals on Jordan and Little Lehigh Creeks, Princeton Hydro partnered with the Wildlands Conservancy again in 2018 to remove a combination of four privately and publicly owned dams on Bushkill Creek in Easton, PA. The dam removal projects served as a model for landowners and municipalities regarding the need for future dam removals throughout the Delaware and Lehigh Valley Watersheds. Having been restored to its natural, free-flowing state in Fall 2024, the barrier removals were part a larger, watershed-wide effort to improve aquatic connectivity, fisheries, and benthic macro-invertebrate and wildlife habitats. The projects restored fish passage, reduced nonpoint source pollution, improved water quality, and restored capacity for groundwater recharge, as well as stabilized and restored the stream’s channels and banks. As part of the barrier removal projects, Princeton Hydro:
Princeton Hydro was contracted by the United States Army Corps of Engineers (USACE) Philadelphia District to perform laboratory testing on vibracore samples collected as part of the State wide beach replenishment project. Vibracore samples were collected by the USACE Wilmington District vessel, Brandy Station, at existing and potential borrow areas located offshore near Cape May, Hereford to Townsends Inlet, Absecon Inlet, Long Beach Island, and Manasquan to Barnegat Inlet. Seventy-nine (79) total vibracore samples were collected, each extending approximately twenty (20) feet below the mudline at each location.
Following the completion of the field investigation, the samples were collected directly from the Government vessel and delivered to Princeton Hydro’s AASHTO accredited and USACE validated soils laboratory for logging and materials testing. From the vibracores, a total of four-hundred and fifty (450) samples were selected for grain size analysis.
A summary report was provided to USACE upon completion of the laboratory testing detailing the methodologies used for laboratory testing, results of the grain size analysis, detailed vibracore logs, and a summary of the soils observed in each of the retrieved vibracore samples.
Princeton Hydro has partnered with Wildlands Conservancy for over a decade on multiple dam removals in the Lehigh River Valley. Our firm designed and permitted the removal of eight consecutive barriers on Jordan Creek, including three consecutive low-head dams. We also designed and permitted two low-head dams on Little Lehigh Creek. Collectively, these dam removal projects reconnected miles of river, enhanced aquatic habitat, and improved adjacent parkland and recreational fishing in the economically-stressed, urban communities of Allentown, PA.
Building upon the successes of the barrier removals on Jordan and Little Lehigh Creeks, Princeton Hydro partnered with the Wildlands Conservancy again in 2018 to remove a combination of four privately and publicly owned dams on Bushkill Creek in Easton, PA. The dam removal projects served as a model for landowners and municipalities regarding the need for future dam removals throughout the Delaware and Lehigh Valley Watersheds.
Having been restored to its natural, free-flowing state in Fall 2024, the barrier removals were part a larger, watershed-wide effort to improve aquatic connectivity, fisheries, and benthic macro-invertebrate and wildlife habitats. The projects restored fish passage, reduced nonpoint source pollution, improved water quality, and restored capacity for groundwater recharge, as well as stabilized and restored the stream’s channels and banks.
As part of the barrier removal projects, Princeton Hydro:
The Arrowhead Lake Community Association, Inc. (ALCA), located in Pocono Lake, Pennsylvania, recognized that the twin corrugated metal culverts passing over Trout Creek were failing. Owassa Drive crosses the culverts and is a primary access for many of the Arrowhead Lake homeowners.
The drainage area to the crossing is nine square miles. Just upstream of the crossing, a dam impounding Brady’s Lake was breached due to the deterioration of the dam. The loss of the Brady’s Lake dam exacerbated the culverts’ deterioration. Another contributing factor to the metal pipe deterioration was the natural low pH (acidic) of the soil and water and the original inadequate backfill technique and materials.
Princeton Hydro analyzed the watershed and determined the hydraulic conditions of the existing culvert as well as a host of replacement options. The ALCA selected a Con-Span culvert with natural bottom due to the capacity, environmental benefits, cost and aesthetics. A geotechnical investigation yielded data on the existing backfill and helped determine that replacement of this material was justified. Field survey was conducted to design the culvert replacement supplemented by an aerial survey of the community. Princeton Hydro permitted the project and construction was completed in June of 2005. Princeton Hydro provided construction administration and oversight during the completion of the culvert replacement.
Keen Road, a local, rural roadway in East Vincent Township is scheduled to be repaved in 2025. There are four culverts under Keen Road that are in poor condition and need to be replaced, with one of them containing an active stream traveling through it. There are erosion issues and safety issues with culverts on both sides of the road, with erosion beginning to undermine the road itself.
Princeton Hydro was contracted by East Vincent Township to develop construction plans to replace the culverts and address the safety and erosion issues before Keen Road is repaved later in 2025. Princeton Hydro had the project area surveyed and used public LiDAR data to build a watershed model to calculate the flow through each of the culverts to determine if they were sized correctly. Without any record drawings of these culverts, Princeton Hydro had to work from scratch to understand how the system currently works and if there would be any ways to improve the performance of the system. Princeton Hydro also coordinated with local and state permitting agencies to attain the necessary permits to install the new culverts.
At the request of the local residents, Princeton proposed to modify the existing layout of the culverts to eliminate the need for two guide rail structures. Princeton Hydro also designed a series of grade control structures along the eastern upstream side of the project area to eliminate the source of the erosion and provide erosion protection along the roadway to stop the undermining of the road. The grade control structures reduce the velocity of the runoff to reduce erosion while also providing armor to provide further protection against erosion. Finally, erosion control measures such as a rip rap apron were designed at the discharge to provide protection from erosion on the downstream side of Keen Road.
The project was put out to bid in November 2024 and is scheduled for construction this Spring 2025.
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 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.
Select staff of Princeton Hydro conducted a Phase I Diagnostic and Feasibility Study of Lake Luxembourg under the Clean Lakes (314) Program with the funds awarded by the U.S. Environmental Protection Agency (USEPA). Lake Luxembourg is located within the Core Creek Watershed with the majority of the watershed located in Core Creek County Park, one of the most heavily utilized parks in Bucks County, PA. Princeton Hydro conducted in-lake and watershed monitoring activities, quantified the annual pollutant (nitrogen, phosphorus, and suspended solids) loads, and developed a Restoration and Management Plan for the lake and watershed. These data were used by Princeton Hydro with the PA Department of Environmental Protection (PADEP) to develop a total phosphorus Total Maximum Daily Load (TMDL) for the lake.
After the Phase I Study was completed, Princeton Hydro designed and implemented a number of Best Management Practices (BMPs). Princeton Hydro assisted the Bucks County Department of Parks and Recreation in obtaining additional funds through the USEPA Non-point Source Pollution Program (319) for the implementation of agricultural BMPs throughout the watershed. A shift from agricultural to residential and commercial land use prompted the development of another NPS project to address these issues. For this, Princeton Hydro assisted the Bucks County Conservation District (BCCD) in obtaining additional funds through the 319 Program. The funds were used for five stream bank and shoreline stabilization projects within the Core Creek County Park.
Princeton Hydro also completed another 319 project that implemented a number of small retrofits to remove phosphorus from stormwater, installed additional vegetative shoreline buffers with the aid of students from Neshaminy Middle School, and created a pocket wetland BMP to continue to reduce the total phosphorous (TP) loads entering the lake.
Finally, Princeton Hydro and Bucks County embarked on an ambitious project to restore the inlet area of the lake, termed the Conservation Pool, into a naturalized stormwater treatment facility. This 17-acre forebay area had filled in with sediment over the decades and had limited capacity to treat the nutrient rich inflowing water. Using nature as a guide, Princeton Hydro designed and implemented a plan to dredge 15,000 cubic yards of phosphorus-rich sediment. Additionally, an emergent wetland system was designed and is currently being installed to better retain sediment and phosphorus before it reaches the main body of the lake. This system included infrastructure to ensure the ongoing maintenance and functionality of this BMP.
Princeton Hydro continues to work closely with all of the stakeholders within the watershed to improve the water quality of Lake Luxembourg and restore Core Creek and its riparian corridor. For example, Princeton Hydro will work with the BCCD in reassessing and updating the stailization practices in other sections of the watershed that have been impacted by both climate change and invasive species.
Princeton Hydro was contracted to investigate, analyze, and design the removal of obstructions and restore natural stream function on Darby Creek. With funding from the National Fish and Wildlife Foundation and Pennsylvania Growing Greener program, the objective of the project was to remove remnant bridge piers in Colwyn and Sharon Hill Boroughs, a failed dam in Darby Borough, a mill dam in Landsdowne and Clifton Heights Boroughs, and a dam in Upper Darby Township and Clifton Heights Borough.
The Kent Park Dam was a placed rock structure that spanned Darby Creek within Kent Park within Delaware County. Princeton Hydro prepared hydrologic and hydraulic analyses; assessed fluvial geomorphic characteristics; determined infrastructure impacts; inventoried natural resources, including wetland delineations and invasive species; and assessed impounded sediment. Design plan sets were prepared, public presentations completed, and permit applications submitted to the Pennsylvania Department of Environmental Protection, U.S. Army Corps of Engineers, and the Delaware County Soil Conservation District.
This project included the reconstruction of the stream bank using bioengineered soil lifts; the innovative construction of a riffle over a sanitary sewer line, which protruded above the stream bed; and the creation of a wetland complex within a small spring tributary to Darby Creek, which reduced sediment contributions to the stream.
Princeton Hydro provided construction observation and administration to ensure the implementation met the stakeholders’ expectations and design intent. This project was funded by the PADEP Growing Greener Grant program, the National Fish and Wildlife Foundation, and a NOAA settlement fund from the 2004 Athos I oil spill on the Delaware River.
Located in Chester County Pennsylvania, just downstream of the Stroud Water Research Center (SWRC), a small segment of the East Branch White Clay Creek, designated as an Exceptional Value (EV) stream and watershed by the Commonwealth of Pennsylvania, was selected as a location for the implementation of a floodplain wetland restoration and reconnection project. The project reach extends downstream from the Spencer Road across properties owned by the SWRC, the Stroud family, and neighboring landowners. This particular stretch of stream had been historically straightened for agricultural purposes, and exhibited signs of geomorphic instability such as re-meandering, incision, and widening due to bank erosion. Additionally, this section is part of a long-term research project in environmental biology conducted by SWRC and funded by the National Science Foundation.
The strategic design, hydrologic and hydraulic analyses, and site evaluations resulted in a design which in addition to grading, utilized the natural topographic controls, such as bedrock and confluences, enabled the filling of the newly constructed floodplain prior to flood peaks. This proactive approach helped to mitigate erosion associated with bank overtopping and the confluence of floodwaters, contributing to the overall reduction of potential risks. All disturbed areas were planted and seeded with native floodplain and upland species to stabilize the site and promote a healthy native plant community. Unique to this project, The material excavated from the floodplain was placed and spread on adjacent actively farmed fields thus utilizing the legacy sediments for future agricultural production.
The incorporation of naturalized, function-based restoration design principles, a hallmark of Princeton Hydro’s expertise, played a central role in restoring and enhancing floodplain function in this context. The successful implementation of the project relied on a delicate balance of considering the maximization of ecological benefits and potential reduction in localized flooding, all within the constraints of realistic funding availability and regulatory compliance.
Princeton Hydro was contracted by American Rivers to design, apply for permits, and provide construction administration services for the removal of the Kehm Run Dam, an earthen embankment, 270-feet long by 22 feet high, with a cast-in-place ogee spillway, about six (6) feet in height. The former impoundment was five (5) acres in size and contained an estimated 40,000 cubic yards of accumulated sediment. Princeton Hydro conducted a bathymetric survey, developed engineering plans, performed hydrologic and hydraulic analysis, applied to PADEP Dam Safety for a Restoration Waiver, and also to the York County Soil Conservation District plan approval. As part of the regulatory activities, Princeton Hydro subcontracted for a bog turtle (Glyptemys muhlenbergii) Phase I assessment, PA Historic and Museum Commission (PHMC) notices, and filed for a PA Fish and Boat Commission (PFBC) water lowering authorization. The dam was breached in 2019, and the project was completed the following year, with follow up site visits in 2021.
The project was challenging due to the quantity of sediment encountered and its fine-grained nature as a colloidal (very small clay particles), with a relatively small stream immediately downstream. As a result of PADEP Dam Safety inspecting the site, expressing their concerns about the quantity of sediment, Princeton Hydro prepared a revised breach design that provided containment of the sediment, while deregulating the dam. As a result, the former lakebed created an opportunity for its use to as a nature-based BMP to address nutrient loading to the Susquehanna River and Chesapeake Bay. The Susquehanna River Basin Commission saw this opportunity and funded a next phase to further enhance the wetlands created to improve sediment capture from the watershed.
This was a challenging project and has been documented by American Rivers in their blog as “Taking the Lemons and Making some Dam Lemonade”. As a project that provided significant lessons in adaptive management and making the most out of a challenging project.
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