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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Yet the performance and longevity of these structures depend just as much on the subsurface conditions beneath them. Geotechnical engineering is the discipline dedicated to investigating, analyzing, and characterizing soil, rock, landscape, and groundwater conditions, and applying that data to the design and construction of safe, resilient, and sustainable infrastructure and restoration projects. At Princeton Hydro, our geotechnical and soils engineers design and execute customized, cost-effective investigations that provide the parameters needed for successful design. Because geotechnical services touch every stage of a project, our integrated approach of investigation, including soils laboratory testing, analysis, and design, all done in-house, ensures streamlined communication, efficiency, and technical excellence. This blog offers a closer look at what geotechnical engineering entails, the specialized capabilities Princeton Hydro provides, and real-world examples of how our work supports resilient, sustainable design. Princeton Hydro’s Geotechnical Capabilities Geotechnical Investigations: Our engineers can perform subsurface investigation, identification, and assessment of accumulated sediment, subsurface soils, and rock, as well as slope stability and stabilization modeling. Our work ranges from foundation type and bearing capacity assessments to mitigation strategies for unsuitable materials. We also regularly conduct forensic geotechnical investigations, which focus on investigating soil-interaction-related failures of engineered infrastructure. Laboratory Testing: We operate an American Association of State Highway and Transportation Officials (AASHTO) Accredited laboratory in Sicklerville, NJ. This allows us to complete 100% of geotechnical investigation planning and oversight, laboratory testing, analysis, design, and reporting in-house. Our geotechnical laboratory performs a full suite of soils and materials testing, including grain size analysis, plasticity index, organic content, moisture content, compaction characteristics of soil (Standard and Modified Proctor), California bearing ratio (CBR), one dimensional consolidation, and flexible and rigid wall permeability testing under constant or falling head conditions. With this capability, we can rapidly deliver high-quality data to inform project design and construction. Our laboratory is also a U.S. Army Corps of Engineers (USACE) Validated Laboratory. Click here to view Princeton Hydro’s complete accreditation listing and certificate. And, click here to learn more about the USACE Materials Testing Laboratories and Validation. Field & Construction Services: Our engineers are experienced in construction requirements, design, and methodology for various structures, as well as field inspections and special testing. We have a Certified Construction Specifier (CCS) on staff and ACI-certified concrete field-testing technicians. Our team performs compaction testing of soil and asphalt using a nuclear density gauge, reinforcing steel inspections, and 2006 International Building Code (IBC) special inspections. We help determine foundation type, site improvements, and optimal construction techniques. Dredging & Sediment Investigations: Over our 25-year history, we’ve managed more than 100 dredging projects across freshwater and estuarine systems. We specialize in beneficial reuse of dredged material for ecological restoration, including wetland creation, thin-layer placement, and living shorelines. Our team provides sediment characterization, slope stability modeling, and contaminant analysis in complex, developed watersheds. Princeton Hydro’s Geotechnical Work in Action To bring this work to life, we’ve chosen a few Princeton Hydro projects that showcase where our geotechnical expertise helped solve unique challenges: Geotechnical Design & Subsurface Investigations for Coastal Wetland Restoration – New York At Spring Creek Park North in Jamaica Bay, New York, decades of urbanization and dredged material placement had degraded more than 40 acres of tidal marsh and uplands. To address this, Princeton Hydro provided subsurface investigations and design services for a large-scale ecosystem restoration led by the USACE New York District, in partnership with NYC Parks. A key design assumption was the reuse of excavated material: soils removed from wetland areas were repurposed to construct upland hills, supporting both ecological function and cost-effective implementation. Our work included geotechnical borings, slope stability analyses, and hydraulic modeling, as well as the collection of topographic and bathymetric survey data, wetland delineations, vegetation assessments, and hydrodynamic measurements. This data informed the development of slope stability and hydraulic models and guided the restoration design. The project advanced through a structured engineering design process — with 30%, 60%, 90%, and 100% design submissions — along with preparation of technical specifications, permit applications, and a detailed construction cost estimate. When complete, the project will restore more than 43 acres of marsh and upland habitat, improving water quality, enhancing biodiversity, and strengthening climate resilience in one of New York City’s most ecologically significant coastal systems. [gallery size="medium" link="none" columns="2" ids="18187,18188"] Offshore Subsurface Investigation for Jetty Reconstruction – Delaware Princeton Hydro was contracted by USACE Philadelphia District to perform offshore subsurface geotechnical investigations in support of reconstructing the Indian River Inlet jetty at Delaware Seashore State Park. Working under challenging marine conditions, our team successfully advanced deep geotechnical borings (to depths of 100 feet) from a lift boat platform, collected soil samples, performed laboratory testing including triaxial strength, consolidation, and direct shear tests; and delivered detailed soil data. Despite difficult sea states, we maintained close communication with USACE to ensure safety and project continuity. The resulting data provided USACE with critical insight into subsurface conditions, helping inform design alternatives for the new jetty structure. [gallery size="medium" columns="2" link="none" ids="18185,18184"] Subsurface Investigations for Dike Raising – New Jersey At the Killcohook Confined Disposal Facility (CDF), Princeton Hydro carried out a large-scale subsurface investigation to support USACE Philadelphia District’s plans for raising the site’s perimeter dikes. The project site, formerly a National Wildlife Refuge, is located in Pennsville, New Jersey, on the eastern bank of the Delaware River, to the north of Fort Mott State Park and adjacent to the Supawna Meadows Wildlife Refuge. Each cell of the CDF receives dredge material from the Delaware River. The subsurface explorations performed by Princeton Hydro were conducted along the existing dike comprising the border of Cell 1 of the CDF. Cell 1 consists of an area of approximately 710 acres with the entire CDF covering 1,200 acres. For this exploration project, Princeton Hydro was tasked with the performance of thirty-one (31) geotechnical borings as well as sixty-five (65) cone penetrometer tests with porewater measurements (CPTu) soundings. Princeton Hydro also provided site safety oversight in accordance with USACE standards. Soil samples were logged and collected by Princeton Hydro and tested at their Sicklerville, New Jersey geotechnical laboratory, which is accredited under the AASHTO Accreditation Program and validated by USACE for soils testing. The data collected is now being used by USACE to design the upgraded dike system, ensuring safe, resilient operation of the facility for future dredged material management. [gallery link="none" columns="2" size="medium" ids="18181,18183"] Comprehensive Geotechnical Investigation and Reporting – New Jersey At the 545-acre Pedricktown North Confined Disposal Facility in Oldmans Township, New Jersey, located on the Delaware River west of Route 130 between Porcupine Road and Pennsgrove-Pedricktown Road, Princeton Hydro conducted a comprehensive subsurface investigation in support of a dike raising project led by the USACE Philadelphia District. As part of this field exploration, our team performed eight geotechnical borings, thirty-eight cone penetrometer tests with porewater measurement (CPTu) soundings, and collected five grab samples. These efforts provided critical soil strength and settlement data to inform USACE’s design of the upgraded dike system. In addition to managing subcontractors and ensuring compliance with USACE safety protocols, Princeton Hydro oversaw the field program, coordinated directly with the Project Manager, and delivered the final geotechnical report. This investigation is supplying USACE with essential geotechnical data to guide the design and construction of the improved dike infrastructure. [gallery link="none" size="medium" ids="18190,18193,18192"] This blog only scratches the surface of what geotechnical engineering entails. To dive deeper, we invite you to read “A Day in the Life: Princeton Hydro’s Geotechnical Laboratory,” where you’ll step into our laboratory and shadow Marissa Ciocco, P.E. as she turns soil samples into the data that drives resilient design. [post_title] => Beneath the Surface: Exploring the World of Geotechnical Engineering [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => beneath-the-surface-exploring-the-world-of-geotechnical-engineering [to_ping] => [pinged] => [post_modified] => 2025-10-15 17:39:54 [post_modified_gmt] => 2025-10-15 17:39:54 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?p=18379 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [1] => WP_Post Object ( [ID] => 18216 [post_author] => 1 [post_date] => 2025-09-11 18:30:35 [post_date_gmt] => 2025-09-11 18:30:35 [post_content] => The Winchell-Smith Dam on the Farmington River in Connecticut has been removed! This long-anticipated project, spearheaded by the Farmington River Watershed Association (FRWA), is a major milestone in the restoration of the Farmington River. The full removal and restoration effort, which began on September 8, reconnects 30 miles of critical upstream habitat. The effort is the result of a robust collaboration among project partners, following years of persistence and careful planning to turn a long-standing vision for the Farmington River into reality. Under the leadership of FRWA, the project partners include Miss Porter's School, the current dam owner; Princeton Hydro, providing engineering, design and project oversight; RiverLogic Solutions; CTDEEP Fisheries; and the Town of Farmington. Together, these partners are advancing ecological restoration, community safety, and recreation access along one of New England's most celebrated rivers. Photo taken September 10 by Princeton Hydro Director of River Restoration & Resilience Christiana Pollack, CERP, CFM, GISP Restoring Natural Function & Reconnecting Habitat The Farmington River, a designated "Partnership Wild & Scenic River," flows for nearly 47 miles along its main stem in northwest Connecticut, with major tributaries extending into southwest Massachusetts. It's longest route, originating from the West Branch, stretches 80.4 miles, making it the longest tributary of the Connecticut River. Its watershed spans more than 600 square miles, providing critical drinking water to hundreds of thousands of people, supporting a world-class trout fishery, and serving as a vital habitat for a variety of resident and migratory species. Nearly 79 miles of the river are federally protected for their outstanding natural, cultural, and recreational values. The Winchell-Smith Dam, a 200-foot-wide, 4-foot-high, low-head timber crib structure, dates back to the early 1600s and may have been the first gristmill ever built on the Farmington River. The dam had long ceased to serve a functional purpose but continued to impede the river's natural process, blocked access for migratory fish, created localized erosion and scour, presented an obstacle for paddlers and anglers, and posed as a safety hazard. [caption id="attachment_15048" align="alignnone" width="1371"] Pre-Construction, Winchell-Smith Dam and Miss Porter’s School Administration Building. Photo by Farmington River Watershed Association.[/caption] Removing the dam delivers myriad benefits to the ecological landscape and surrounding community. Most significantly, it reopens 30 miles of historic spawning habitat for species such as American shad, alewife, blueback herring, sea lamprey, and American eel, and provides unobstructed access to the upper reaches of the river and its tributaries. The restored river channel will support healthier fish populations, stabilize riverbanks, reestablish important wildlife habitat, and improve water quality. Additionally, the project enhances public safety by eliminating a hazardous low-head dam and expands opportunities for nature-based recreation along this cherished waterway. The photos below, taken by Princeton Hydro Senior Fluvial Geomorphologist Casey Clapsaddle, show the rapid progress being made at the Winchell-Smith Dam site: [gallery columns="2" link="none" size="medium" ids="18225,18228,18226,18227"] A Decade in the Making Princeton Hydro's involvement at the Winchell-Smith Dam site dates back to 2009, when the engineering team worked with FRWA to complete early assessments and developed a design for a nature-like fishway. Funding constraints and the dam's continued deterioration ultimately made full removal the only viable option. With funding support from CTDEEP Fisheries, the effort to fully remove Winchell-Smith Dam was finally able to advance. Princeton Hydro provided comprehensive engineering services, including site investigation and geomorphic inspection, wetland delineation, hydrologic assessment and hydraulic modeling, permitting, and construction oversight. The removal of the Winchell-Smith Dam is part of a larger restoration plan initiated by FRWA and Princeton Hydro, which included the removal of the Spoonville Dam. The 35-foot-high concreate dam once stood as the first barrier to fish passage on the Farmington River. Photos from the Spoonville Dam Removal in 2009: [gallery link="none" ids="10435,10441,10440"] Honoring History & Celebrating the Future While the Winchell-Smith Dam itself is being dismantled, its history will not be lost. Timbers from the structure are being preserved and repurposed for educational objectives, honoring the site's industrial legacy while celebrating its ecological renewal. Rocks and boulders from the dam will also be used to restore the river location, constructing a riffle-like condition in the riverbed. The project also aims to foster the next generation of environmental stewards by engaging the students at Miss Porter's School and local public schools. Throughout the process, students are participating in hands-on activities that deepen their understanding of river restoration and introduce them to STEM subjects like engineering and ecology. As demolition progresses, partners, community members, and environmental advocates are celebrating the return of a free-flowing Farmington River and looking forward to its continued transformation. Stay tuned to for more updates! To learn more about FRWA, visit their website or click here to read our Client Spotlight blog featuring Executive Director Aimee Petras. This blog was updated on October 15, 2025. [post_title] => Restoring the Farmington River: Winchell-Smith Dam Removal is Complete! [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => restoring-the-farmington-river-winchell-smith-dam-removal-is-underway [to_ping] => [pinged] => [post_modified] => 2025-10-15 18:22:10 [post_modified_gmt] => 2025-10-15 18:22:10 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?p=18216 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [2] => WP_Post Object ( [ID] => 18009 [post_author] => 1 [post_date] => 2025-08-07 19:26:22 [post_date_gmt] => 2025-08-07 19:26:22 [post_content] => We're pleased to announce the release of the "New Jersey Nature-Based Solutions: Planning, Implementation, and Monitoring Reference Guide," a free resource that provides a comprehensive roadmap to incorporating nature-based solutions (NBS) into infrastructure, construction, restoration, and resilience projects across the state. Created by the Rutgers University New Jersey Climate Change Resource Center with support from The Nature Conservancy in New Jersey, the guide compiles current research, case studies, best practices, practical tools, science-based strategies, and funding resources to "inform and empower readers to implement and seek funding for NBS." Click here to view and download the guide now. Inside the Guide As the guide states, "nature-based solutions (NBS) are defined as actions to protect, sustainably manage, and restore natural and modified ecosystems that address societal challenges effectively and adaptively, simultaneously benefiting people and nature." (IUCN 2024) Whether you're a municipal planner, community leader, contractor, public- or private-sector professional, or an academic, new to NBS or experienced in large-scale restoration projects, the guide offers value at every level with practical instruction that spans the full project lifecycle, from planning and permitting to funding and long-term monitoring. While the content is tailored to New Jersey's diverse landscapes, the guide's insights and approaches are broadly applicable to regions with similar ecosystems, from Massachusetts to Virginia. The guide equips readers with:
When most people think of engineering, they picture bridges, buildings, and dams rising above the landscape. Yet the performance and longevity of these structures depend just as much on the subsurface conditions beneath them. Geotechnical engineering is the discipline dedicated to investigating, analyzing, and characterizing soil, rock, landscape, and groundwater conditions, and applying that data to the design and construction of safe, resilient, and sustainable infrastructure and restoration projects.
At Princeton Hydro, our geotechnical and soils engineers design and execute customized, cost-effective investigations that provide the parameters needed for successful design. Because geotechnical services touch every stage of a project, our integrated approach of investigation, including soils laboratory testing, analysis, and design, all done in-house, ensures streamlined communication, efficiency, and technical excellence.
This blog offers a closer look at what geotechnical engineering entails, the specialized capabilities Princeton Hydro provides, and real-world examples of how our work supports resilient, sustainable design.
Geotechnical Investigations: Our engineers can perform subsurface investigation, identification, and assessment of accumulated sediment, subsurface soils, and rock, as well as slope stability and stabilization modeling. Our work ranges from foundation type and bearing capacity assessments to mitigation strategies for unsuitable materials. We also regularly conduct forensic geotechnical investigations, which focus on investigating soil-interaction-related failures of engineered infrastructure.
Laboratory Testing: We operate an American Association of State Highway and Transportation Officials (AASHTO) Accredited laboratory in Sicklerville, NJ. This allows us to complete 100% of geotechnical investigation planning and oversight, laboratory testing, analysis, design, and reporting in-house. Our geotechnical laboratory performs a full suite of soils and materials testing, including grain size analysis, plasticity index, organic content, moisture content, compaction characteristics of soil (Standard and Modified Proctor), California bearing ratio (CBR), one dimensional consolidation, and flexible and rigid wall permeability testing under constant or falling head conditions. With this capability, we can rapidly deliver high-quality data to inform project design and construction. Our laboratory is also a U.S. Army Corps of Engineers (USACE) Validated Laboratory. Click here to view Princeton Hydro’s complete accreditation listing and certificate. And, click here to learn more about the USACE Materials Testing Laboratories and Validation.
Field & Construction Services: Our engineers are experienced in construction requirements, design, and methodology for various structures, as well as field inspections and special testing. We have a Certified Construction Specifier (CCS) on staff and ACI-certified concrete field-testing technicians. Our team performs compaction testing of soil and asphalt using a nuclear density gauge, reinforcing steel inspections, and 2006 International Building Code (IBC) special inspections. We help determine foundation type, site improvements, and optimal construction techniques.
Dredging & Sediment Investigations: Over our 25-year history, we’ve managed more than 100 dredging projects across freshwater and estuarine systems. We specialize in beneficial reuse of dredged material for ecological restoration, including wetland creation, thin-layer placement, and living shorelines. Our team provides sediment characterization, slope stability modeling, and contaminant analysis in complex, developed watersheds.
To bring this work to life, we’ve chosen a few Princeton Hydro projects that showcase where our geotechnical expertise helped solve unique challenges:
At Spring Creek Park North in Jamaica Bay, New York, decades of urbanization and dredged material placement had degraded more than 40 acres of tidal marsh and uplands. To address this, Princeton Hydro provided subsurface investigations and design services for a large-scale ecosystem restoration led by the USACE New York District, in partnership with NYC Parks.
A key design assumption was the reuse of excavated material: soils removed from wetland areas were repurposed to construct upland hills, supporting both ecological function and cost-effective implementation. Our work included geotechnical borings, slope stability analyses, and hydraulic modeling, as well as the collection of topographic and bathymetric survey data, wetland delineations, vegetation assessments, and hydrodynamic measurements. This data informed the development of slope stability and hydraulic models and guided the restoration design.
The project advanced through a structured engineering design process — with 30%, 60%, 90%, and 100% design submissions — along with preparation of technical specifications, permit applications, and a detailed construction cost estimate. When complete, the project will restore more than 43 acres of marsh and upland habitat, improving water quality, enhancing biodiversity, and strengthening climate resilience in one of New York City’s most ecologically significant coastal systems.
Princeton Hydro was contracted by USACE Philadelphia District to perform offshore subsurface geotechnical investigations in support of reconstructing the Indian River Inlet jetty at Delaware Seashore State Park. Working under challenging marine conditions, our team successfully advanced deep geotechnical borings (to depths of 100 feet) from a lift boat platform, collected soil samples, performed laboratory testing including triaxial strength, consolidation, and direct shear tests; and delivered detailed soil data. Despite difficult sea states, we maintained close communication with USACE to ensure safety and project continuity.
The resulting data provided USACE with critical insight into subsurface conditions, helping inform design alternatives for the new jetty structure.
At the Killcohook Confined Disposal Facility (CDF), Princeton Hydro carried out a large-scale subsurface investigation to support USACE Philadelphia District’s plans for raising the site’s perimeter dikes. The project site, formerly a National Wildlife Refuge, is located in Pennsville, New Jersey, on the eastern bank of the Delaware River, to the north of Fort Mott State Park and adjacent to the Supawna Meadows Wildlife Refuge. Each cell of the CDF receives dredge material from the Delaware River. The subsurface explorations performed by Princeton Hydro were conducted along the existing dike comprising the border of Cell 1 of the CDF. Cell 1 consists of an area of approximately 710 acres with the entire CDF covering 1,200 acres.
For this exploration project, Princeton Hydro was tasked with the performance of thirty-one (31) geotechnical borings as well as sixty-five (65) cone penetrometer tests with porewater measurements (CPTu) soundings. Princeton Hydro also provided site safety oversight in accordance with USACE standards. Soil samples were logged and collected by Princeton Hydro and tested at their Sicklerville, New Jersey geotechnical laboratory, which is accredited under the AASHTO Accreditation Program and validated by USACE for soils testing.
The data collected is now being used by USACE to design the upgraded dike system, ensuring safe, resilient operation of the facility for future dredged material management.
At the 545-acre Pedricktown North Confined Disposal Facility in Oldmans Township, New Jersey, located on the Delaware River west of Route 130 between Porcupine Road and Pennsgrove-Pedricktown Road, Princeton Hydro conducted a comprehensive subsurface investigation in support of a dike raising project led by the USACE Philadelphia District.
As part of this field exploration, our team performed eight geotechnical borings, thirty-eight cone penetrometer tests with porewater measurement (CPTu) soundings, and collected five grab samples. These efforts provided critical soil strength and settlement data to inform USACE’s design of the upgraded dike system.
In addition to managing subcontractors and ensuring compliance with USACE safety protocols, Princeton Hydro oversaw the field program, coordinated directly with the Project Manager, and delivered the final geotechnical report. This investigation is supplying USACE with essential geotechnical data to guide the design and construction of the improved dike infrastructure.
The Winchell-Smith Dam on the Farmington River in Connecticut has been removed! This long-anticipated project, spearheaded by the Farmington River Watershed Association (FRWA), is a major milestone in the restoration of the Farmington River. The full removal and restoration effort, which began on September 8, reconnects 30 miles of critical upstream habitat.
The effort is the result of a robust collaboration among project partners, following years of persistence and careful planning to turn a long-standing vision for the Farmington River into reality. Under the leadership of FRWA, the project partners include Miss Porter's School, the current dam owner; Princeton Hydro, providing engineering, design and project oversight; RiverLogic Solutions; CTDEEP Fisheries; and the Town of Farmington. Together, these partners are advancing ecological restoration, community safety, and recreation access along one of New England's most celebrated rivers.
The Farmington River, a designated "Partnership Wild & Scenic River," flows for nearly 47 miles along its main stem in northwest Connecticut, with major tributaries extending into southwest Massachusetts. It's longest route, originating from the West Branch, stretches 80.4 miles, making it the longest tributary of the Connecticut River. Its watershed spans more than 600 square miles, providing critical drinking water to hundreds of thousands of people, supporting a world-class trout fishery, and serving as a vital habitat for a variety of resident and migratory species. Nearly 79 miles of the river are federally protected for their outstanding natural, cultural, and recreational values.
The Winchell-Smith Dam, a 200-foot-wide, 4-foot-high, low-head timber crib structure, dates back to the early 1600s and may have been the first gristmill ever built on the Farmington River. The dam had long ceased to serve a functional purpose but continued to impede the river's natural process, blocked access for migratory fish, created localized erosion and scour, presented an obstacle for paddlers and anglers, and posed as a safety hazard.
Removing the dam delivers myriad benefits to the ecological landscape and surrounding community. Most significantly, it reopens 30 miles of historic spawning habitat for species such as American shad, alewife, blueback herring, sea lamprey, and American eel, and provides unobstructed access to the upper reaches of the river and its tributaries. The restored river channel will support healthier fish populations, stabilize riverbanks, reestablish important wildlife habitat, and improve water quality. Additionally, the project enhances public safety by eliminating a hazardous low-head dam and expands opportunities for nature-based recreation along this cherished waterway.
The photos below, taken by Princeton Hydro Senior Fluvial Geomorphologist Casey Clapsaddle, show the rapid progress being made at the Winchell-Smith Dam site:
Princeton Hydro's involvement at the Winchell-Smith Dam site dates back to 2009, when the engineering team worked with FRWA to complete early assessments and developed a design for a nature-like fishway. Funding constraints and the dam's continued deterioration ultimately made full removal the only viable option. With funding support from CTDEEP Fisheries, the effort to fully remove Winchell-Smith Dam was finally able to advance.
Princeton Hydro provided comprehensive engineering services, including site investigation and geomorphic inspection, wetland delineation, hydrologic assessment and hydraulic modeling, permitting, and construction oversight.
The removal of the Winchell-Smith Dam is part of a larger restoration plan initiated by FRWA and Princeton Hydro, which included the removal of the Spoonville Dam. The 35-foot-high concreate dam once stood as the first barrier to fish passage on the Farmington River.
While the Winchell-Smith Dam itself is being dismantled, its history will not be lost. Timbers from the structure are being preserved and repurposed for educational objectives, honoring the site's industrial legacy while celebrating its ecological renewal. Rocks and boulders from the dam will also be used to restore the river location, constructing a riffle-like condition in the riverbed.
The project also aims to foster the next generation of environmental stewards by engaging the students at Miss Porter's School and local public schools. Throughout the process, students are participating in hands-on activities that deepen their understanding of river restoration and introduce them to STEM subjects like engineering and ecology.
As demolition progresses, partners, community members, and environmental advocates are celebrating the return of a free-flowing Farmington River and looking forward to its continued transformation. Stay tuned to for more updates!
To learn more about FRWA, visit their website or click here to read our Client Spotlight blog featuring Executive Director Aimee Petras.
We're pleased to announce the release of the "New Jersey Nature-Based Solutions: Planning, Implementation, and Monitoring Reference Guide," a free resource that provides a comprehensive roadmap to incorporating nature-based solutions (NBS) into infrastructure, construction, restoration, and resilience projects across the state.
Created by the Rutgers University New Jersey Climate Change Resource Center with support from The Nature Conservancy in New Jersey, the guide compiles current research, case studies, best practices, practical tools, science-based strategies, and funding resources to "inform and empower readers to implement and seek funding for NBS."
Click here to view and download the guide now.
As the guide states, "nature-based solutions (NBS) are defined as actions to protect, sustainably manage, and restore natural and modified ecosystems that address societal challenges effectively and adaptively, simultaneously benefiting people and nature." (IUCN 2024)
Whether you're a municipal planner, community leader, contractor, public- or private-sector professional, or an academic, new to NBS or experienced in large-scale restoration projects, the guide offers value at every level with practical instruction that spans the full project lifecycle, from planning and permitting to funding and long-term monitoring. While the content is tailored to New Jersey's diverse landscapes, the guide's insights and approaches are broadly applicable to regions with similar ecosystems, from Massachusetts to Virginia.
The guide also includes insights on how to address equity considerations and foster meaningful community engagement, helping users implement NBS that are both impactful and inclusive.
Princeton Hydro was proud to contribute technical expertise to this important effort. Our Director of Restoration & Resilience, Christiana L. Pollack, CERP, CFM, GISP, participated on the guide's steering committee, and our team provided informational resources, including content and case studies on invasive species management, wetland and floodplain enhancement, and dam and culvert removal to restore rivers and improve fish passage. These contributions along with those from many other participants, reflect the collaborative nature of the guide and the collective commitment to advancing NBS across the state.
The guide's easy-to-follow format includes four key sections:
Whether you're just beginning to conceptualize a project or deep into project implementation, this guide is an invaluable addition to your toolbox. We encourage you to explore, download, and share it widely! Click here to access the guide now.
Welcome to our “A Day in the Life” blog series, where we explore the diverse expertise and everyday experiences of the professionals who power Princeton Hydro’s mission. In this edition, we follow Casey Pantaleo, PE, a licensed Professional Engineer and Senior Project Manager on the Engineering Services team as he performs one of his highly specialized roles: dam inspection.
Casey meets the New Jersey Department of Environmental Protection (NJDEP)’s criteria for a “qualified engineer,” meaning he is licensed in New Jersey, has more than a decade of relevant experience in dam design, construction, operation, and evaluation, and possesses a deep understanding of the potential causes and consequences of dam failures. He routinely conducts detailed inspections to help ensure the safety and stability of dams across New Jersey and throughout the Northeast.
These structures, which play crucial roles in flood control, water supply, and recreation, require routine maintenance and monitoring to protect downstream communities and preserve infrastructure integrity.
Spend a day with Casey and you’ll quickly realize that dam safety inspection is anything but routine—it’s equal parts technical expertise, historical context, and regulatory navigation, along with a good pair of waterproof boots.
Before heading into the field, the inspection process begins with reviewing the dam’s existing documentation; the scope of that review depends on the type of inspection being conducted.
For a Formal Inspection, the process requires an in-depth review of all available records on the dam. This typically takes place in person at the NJDEP Bureau of Dam Safety office and should be completed prior to the field visit.
For a Regular Inspection, the inspector reviews the most recent inspection report, the dam’s Emergency Action Plan (EAP), and the Operation and Maintenance (O&M) Manual. This step is essential for understanding the dam’s history, known concerns, and any previous recommendations or repairs.
Both inspection types involve a detailed on-site visual examination of the dam. The Bureau of Dam Safety provides a standardized inspection checklist that guides this process. The checklist includes specific criteria for earthen embankments, concrete/masonry dams, and their spillway structures.
“For earthen embankment dams, we assess the overall alignment, crest, upstream and downstream slopes, and dam abutments,” explains Casey. “We’re looking for signs of settlement, depressions, slope instability, seepage, and other indicators of distress.”
For concrete dams, inspectors evaluate the upstream and downstream faces, crest, foundation, abutments, and any interior galleries. The key concerns here are material condition, cracking, seepage, and structural movement.
The spillway, which is often inspected last, requires identification of all structures associated with overflow and release. Depending on the dam’s configuration, this may include primary, secondary, or emergency spillways.
Components typically observed include:
“Every dam is different,” Casey adds. “Not all structures have every component listed on the checklist, so part of our job is tailoring the inspection to the specific site configuration.”
The Formal Inspections checklist also includes a review and description of previous engineering studies and analyses, which ensures the dam continues to meet regulatory requirements. These formal evaluations are required every six years for Class I (high hazard) dams, and every ten years for Class II (significant hazard) dams.
All findings from both the field inspection and records review are compiled into a detailed inspection report, which includes photographic documentation and a formal condition rating:
The report also outlines a compliance schedule, proposing timelines for maintenance work, additional studies, or other corrective actions. Once complete, the report is signed and sealed by a licensed Professional Engineer (PE) and submitted to both the client and the Bureau of Dam Safety.
With the planning and records review process complete, Casey prepares for the physical site visit. Dam inspections often require a full day in the field, so preparation is key.
The first step before heading to the site is preparing an Activity Hazards Analysis (AHA). This document outlines the specific activities planned during the inspection, identifies potential hazards associated with each task, and defines the control measures used to eliminate or reduce risk. The AHA also includes the location of the nearest hospital or urgent care facility in case of injury.
Common hazards associated with dam inspections include slips, trips, and falls, insect nests, poison ivy, working near water, and occasionally, working on or near active roadways. Seasonal risks are also considered, such as the potential for heat illnesses during the summer months or cold-related injuries in the winter.
With safety protocols in place, Casey reviews the inspection schedule, checks the weather forecast, prints site maps, and gathers all the necessary personal protective equipment—waders, hard hat, and high-visibility vest—along with essential tools like a tape measure, measuring wheel, tile probe, field notebook, and camera.
Each tool plays a specific role. The tape measure is used for small-scale assessments, such as measuring cracks or depressions. The measuring wheel helps determine distances between notable features onsite. The tile probe allows Casey to gauge the density and consistency of embankment soils and to investigate for voids in concrete structures. It also comes in handy for checking the depth of animal burrows or the extent of subsurface voids within the dam.
“Having the right measuring tools is absolutely essential,” Casey explains. “We aim to collect the most detailed measurements possible so future inspections can determine whether a condition is getting worse. We also try to anticipate every potential hazard and ensure we have everything we might need before leaving the office. Sometimes we’re hiking through thick brush to reach a spillway or crawling into an outlet conduit—so having a solid plan and the right gear isn’t just helpful, it’s critical.”
Today’s inspection takes place at Assunpink Dam #6, an earth embankment dam located in Robbinsville Township, Mercer County, New Jersey. Built in 1975, the dam is part of a flood control system designed to reduce risks along Assunpink Creek. The structure stands 31 feet high and stretches 2,500 feet long, with a total storage capacity of 12,653 acre-feet. It features a concrete spillway and an upstream water control structure. Owned by the New Jersey Division of Fish & Wildlife, the dam is regulated by the state and classified as a high-hazard structure—meaning its failure could result in significant downstream impacts, making regular inspections essential.
To begin the inspection, Casey walks the full length of the embankment, conducting a detailed visual assessment. He looks for telltale warning signs: animal burrows, seepage, erosion, settlement, slope instability, and woody vegetation that could damage the dam face or block visibility during future inspections. One of the most common and problematic issues he encounters is overgrown vegetation, which can significantly hinder the ability to properly evaluate the structure. Keeping the dam clear is critical for spotting early warning signs and maintaining long-term safety.
“Each dam tells its own story,” Casey explains. “Some may show signs of movement, others are perfectly stable. One site might have seepage issues, while another remains completely dry. It all depends on the structure and how it’s aged.”
He carefully inspects the embankment and associated structures for signs of movement, depressions, sloughing, cracking, and uncontrolled seepage, any of which could indicate an underlying issue that requires remediation.
“We follow a standard checklist during every inspection, but each dam is unique,” he adds. “Part of the job is understanding how these systems were built—some decades or even over a century ago—and how they’ve changed over time.”
After completing the full inspection, including the downstream toe, abutments, and emergency spillway, Casey wraps up his field notes, double-checks measurements, and ensures that all required photos have been captured. Before leaving the site, he often debriefs with the site representative, noting any immediate maintenance needs and outlining the next steps in the reporting process.
Back in the office, Casey begins transcribing his notes into a formal inspection report. He uploads and labels photos, updates GIS data where applicable, and reviews the dam’s historical inspection records to identify long-term trends or recurring issues. These records often help tell a broader story about the structure’s condition over time, highlighting vegetation growth, erosion patterns, or the effectiveness of past repairs.
Safety is always the top priority. If the inspection reveals anything that could pose an immediate risk to people or property downstream, such as uncontrolled seepage, excessive settlement, or slope instability, Casey contacts the dam owner and the NJDEP right away to recommend prompt action. Beyond urgent concerns, the inspection report also includes recommendations for routine maintenance and identifies any outdated analyses or studies that should be updated.
In many cases, the findings involve standard upkeep: clearing overgrown vegetation, reseeding disturbed areas, monitoring minor cracks or depressions, or maintaining access to critical features. One frequently emphasized point is the importance of operating the dam’s low-level outlet, if one is present, on a regular basis. Doing so helps ensure the outlet remains free of sediment or debris and functions properly in an emergency when water levels need to be lowered quickly.
New Jersey is home to more than 1,700 dams, according to data from NJDEP Bureau of Dam Safety. These regulated structures range from low-hazard to high-hazard classifications, the latter being dams whose failure could result in significant property damage or loss of life. Regular inspections are not only a regulatory requirement, but a frontline defense against catastrophic failure. They help identify small problems before they become serious, support safe operation, and guide critical maintenance and repair decisions that protect both people and ecosystems.
“Dam inspection doesn’t always get the spotlight, but it’s essential,” says Casey. “We’re helping communities prevent disasters before they happen by keeping a close eye on structures that quietly serve very big purposes.”
For more information about New Jersey’s dam infrastructure and safety programs, go here!
Casey Pantaleo, PE has over a decade of experience in the Geotechnical Engineering field and expertise in dam inspection, stormwater infrastructure, and regulatory permitting. He is a licensed Professional Engineer in New Jersey, Pennsylvania, Connecticut, Delaware, Maryland, and New York. He maintains a wide range of professional responsibilities for the firm including subsurface explorations, development of geotechnical laboratory testing programs, shallow and deep foundation analysis and design, settlement evaluation, earth retaining system design, slope stability analyses, and management of geotechnical field operations. He also has extensive experience with stormwater infiltration analysis and testing, as well as performing annual dam inspections in compliance with the NJDEP Division of Dam Safety. He completes regular inspection reports, as well as reviews of O&M Manuals and Emergency Action Plans. He has experience with the design of dams for rehabilitation, preparation of engineering plans, and submission of relevant dam permits.
Casey earned his Master of Science in Civil Engineering with a Geotechnical focus from Rowan University. While at Rowan he performed comprehensive research on the effects of particle morphology in geotechnical testing using discrete element modeling and has several peer reviewed journal and conference publications outlining the results of this research.
Princeton Hydro President Geoffrey M. Goll, PE, recently traveled to Durban, South Africa, to participate in a symposium focused on “Dam Management and Restoration of River Connectivity.”
Organized by the Ruben Rocha of the Dam Removal South Africa initiative of the former World Fish Migration Foundation (WFMF) and the Institute of Natural Resources (INR), this inaugural event brought together international experts, local researchers, and representatives from government agencies and environmental organizations to explore the complex challenges of balancing water security with ecosystem protection in South Africa. The dynamic two-day program featured on-site exploration, expert-led presentations, and collaborative “World Cafe” workshops aimed at advancing sustainable water management practices across South Africa.
The workshop kicked off with a visit to two weirs on the lower uMkhomazi River: the Goodenough Weir and the Department of Water and Sanitation Weir. Participants gained a firsthand perspective on the intricate and difficult balance between infrastructure development and ecosystem function preservation. At the Goodenough Weir, construction efforts to upgrade the structure were underway, incorporating a fish passage designed to support the upstream migration of native fish species. In contrast, just upstream, the outdated Department of Water and Sanitation Weir presented a stark example of the challenges posed by aging infrastructure. Its obsolete design continues to block river connectivity and disrupt natural habitats, impeding the broader success of restoration efforts downstream. The success of the Goodenough Weir’s fish passage structure will be evaluated for its effectiveness once in operation.
This field visit provided an immersive learning experience, sparking meaningful discussions among attendees. Participants explored strategies for harmonizing ecological priorities with critical infrastructure needs, emphasizing the importance of collaboration and adopting a holistic, big-picture approach to sustainable water management and river connectivity.
The second day of the workshop was packed with impactful presentations and interactive discussions, offering both local and international perspectives on sustainable water management and river restoration.
South African representatives shared innovative strategies and real-world examples from their work:
Navashni Govender of SANParks highlighted South Africa's groundbreaking efforts in Kruger National Park, where dam removals—the first of their kind on the African continent—have restored natural river flow and enhanced biodiversity.
Nkosinjani Mkhize of the Pongola-Umzimkhulu Catchment Management Agency discussed strategies for balancing social and ecological demands.
Futhi Vilakazi of uMngeni-uThukela Water addressed the dual challenge of securing water supplies and protecting ecosystems, with a focus on catchment interventions.
Dr. Andrew Blackmore of KZN Wildlife provided a detailed exploration of South Africa’s complex regulatory framework for dam removal, shedding light on how to navigate environmental legislation effectively.
The program also welcomed two international experts who enriched the conversation with perspectives from their respective regions:
Princeton Hydro President Geoffrey M. Goll, PE delivered a presentation titled “Sediment Management Before, During, and After Dam/Weir Removal,” emphasizing the critical role of sediment in maintaining river health. Through case studies and strategies from the United States, he demonstrated how proactive sediment management can enhance both the ecological and social benefits of barrier removal. His insights underscored the interconnected challenges of sedimentation, water quality, and dam removal—issues South Africa must address to achieve sustainable water resource management.
Mr. Hamish Moir of Scotland’s CBEC Eco-Engineering shared success stories from Europe, including projects in Scotland, the UK, and Iceland. His presentation on reconnecting rivers through selective barrier removal showcased how nature-based solutions can improve ecosystem dynamics and mitigate flood risks, offering valuable lessons for South Africa.
The day concluded with interactive "World Café" workshop sessions focused on key themes such as stakeholder involvement, governance mechanisms, water scarcity, biodiversity, socio-economic impacts, and funding models. Participants explored solutions for integrating ecological, social, and economic priorities into river restoration projects.
Together, the presentations and workshops provided actionable knowledge and innovative approaches to advancing river connectivity and sustainable dam management.
After the conference, Geoff had the honor of being invited by Dr. Matthew Burnett to tour the University of KwaZulu-Natal’s hydraulics lab. Dr. Burnett, who serves as Principal Scientist at the Institute of Natural Resources, Honorary Freshwater Ecology Researcher at the University of KwaZulu-Natal, and coordinator of the “Dam Management and Restoration of River Connectivity” symposium, introduced Geoff to the research being conducted at the University. Researchers there are developing sediment transport models and fish passage testing methods. The emerging program reflects South Africa’s growing commitment to tackling water scarcity, sedimentation, and ecosystem health.
Geoff noted that South Africa is at a pivotal stage in balancing water security with ecological protection. Many dams, while designed for long-term water availability, struggle with sedimentation that reduces reservoir capacity and leads to water quality issues like harmful algal blooms, in addition to creating barriers for diadromous and potamodromous fish, prawn, and crab species. These challenges highlight the need for integrated solutions that address human, agricultural, and biodiversity needs, ensuring sustainable outcomes.
“It was an honor to be invited to South Africa to participate in this important workshop and collaborate with so many talented individuals, all while gaining a deeper understanding of the country’s water resource challenges,” said Geoff. “By exchanging knowledge and ideas from around the world, we can foster innovative approaches and shape balanced solutions.”
Geoff’s participation exemplifies Princeton Hydro’s commitment to advancing global river restoration efforts. By sharing expertise and fostering collaborative dialogue, the workshop in Durban marked a meaningful step toward reconnecting South Africa’s rivers and creating a more sustainable future for its communities and ecosystems.
Before the workshop, Geoff and his wife, Amy, began the trip in Cape Town immersing themselves in South Africa’s rich culture and natural beauty. They explored the city, took part in a guided history tour, and visited the Cape of Good Hope where they admired the stunning coastal landscape, vibrant flora, and fascinating wildlife, including African penguins!
The removal of Paulina Lake Dam marks a significant step in restoring the Paulins Kill River. With the spillway demolished, dredging completed, and the trail bridge stabilized as of October 2024, the transformation has been remarkable. A new project video now captures this rapid evolution and celebrates the progress made.
We invite you to watch the new video documenting the removal process for the Paulina Lake Dam. The video's captivating aerial footage, taken by The Nature Conservancy (TNC) Volunteer Drone Team before demolition and by Princeton Hydro throughout and after the removal process, showcases the dramatic transformation of the site. The video walks viewers through each removal phase, from initial notching to full demolition, while highlighting what’s next in the ongoing Paulins Kill River restoration effort.
The removal of Paulina Lake Dam is part of a broader effort to restore the Paulins Kill River and its ecosystem. Since 2019, four dam removals, including Columbia Lake’s remnant and main dams (2019), County Line Dam (2022), and Paulina Lake Dam (2024), have reconnected 45 miles of river habitat, allowing native species like brook trout and migratory fish to thrive.
Beyond enhancing aquatic and terrestrial connectivity, the dam’s removal mitigates safety hazards, improves water quality, and expands recreational opportunities for the community. It also contributes to ongoing wetland and riparian zone restoration, including the reforestation of the floodplain and protection of critical habitats.
While the dam is gone, restoration efforts are not quite over. In early Spring, the project team will initiate the third and final project phase by visiting the site to assess and plan for adaptive management work, which will commence in July 2025. During this final push, the project team will enhance habitat features, stabilize riverbanks in select locations, and plant native trees, ensuring a thriving ecosystem for years to come. Stay tuned for more updates as we continue to witness the transformation of the Paulins Kill.
Rivers are the lifeblood of ecosystems, weaving through landscapes to connect habitats, sustain biodiversity, and provide vital resources to communities. Yet, rivers around the world are disrupted by outdated dams, weirs, culverts, and other blockages that fragment habitats, block fish migration, and degrade ecological health. The consequences are far-reaching, threatening not only ecosystems but also the communities that depend on healthy rivers.
Research by the European Open Rivers Programme has highlighted both the urgent need for action and the immense potential of dam removal to restore ecosystems, improve biodiversity, and revive natural river connectivity.
Since 2022, Princeton Hydro President and Principal Geoffrey M. Goll, PE, an expert in water resources engineering, has been collaborating with organizations in Portugal to advance shared goals of river restoration and ecosystem revitalization. In October 2024, Mr. Goll traveled to Portugal, where he met with the organizations driving forward the country’s ecosystem restoration efforts and visited the sites of three key projects he has, or is currently collaborating on.
This blog explores those restoration efforts, highlighting how they address the challenges of river fragmentation while establishing a blueprint for future restoration efforts.
One of the most significant examples of these collaborative restoration efforts is the groundbreaking Galaxes Weir Removal project, which set the stage for future initiatives by addressing river fragmentation on Portugal’s Odeleite River.
Galaxes Weir Removal project in Portugal's Algarve Region marked the country’s first civil removal of an obsolete river barrier to benefit migratory fish species. Associação Natureza Portugal in association with World Wildlife Fund Portugal (ANP/WWF), a non-profit NGO dedicated to the conservation of nature and the protection of the planet, reached out to Mr. Goll and Ms. Lisa Hollingsworth-Segedy of American Rivers, to undertake this pioneering effort.
Completed in March 2023, the removal of the 2-meter-high Galaxes Weir restored 7.7 kilometers of river connectivity, aiding in the preservation of critical fish species such as the Spanish minnowcarp (Anaecypris hispanica) and the critically endangered European eel (Anguilla anguilla). By improving river flow and ecological conditions, the project also bolstered economically vital fisheries, enhanced recreational opportunities, and supported local tourism, establishing a model for future restoration initiatives. Funding for the Galaxes Weir removal was provided by the European Open Rivers Programme (EORP), a grant-giving organization dedicated to restoring European rivers. The international partnership that brought Mr. Goll and Ms. Hollingsworh-Segedy into the fold was facilitated by connections made through the World Fish Migration Foundation. He and Ms. Hollingsworth-Segedy were asked to provide guidance on the de-construction of this concrete structure.
The success of the Galaxes Weir Removal project highlights the importance of both engineering knowledge and techniques, as well as community engagement. By involving local communities throughout the process, the project fostered a sense of shared responsibility and ensured that the ecological and cultural value of the river was preserved. It also underscored the benefits of dam removal as a swift and effective strategy to enhance biodiversity and promote sustainable river management.
Building on the success of the Galaxes Weir removal, the ANP/WWF team expanded its efforts to Santarém, Portugal, northeast of Lisbon, on the Perofilho Stream, a tributary of the Tejo River. The Perofilho Weir, a 2-meter-high concrete barrier, fragmented habitats and disrupted the natural flow of the stream. The National Authority for Nature and Forests Conservation (ICNF) identified the Galaxes Weir as one of the obsolete barriers to be removed to improve fish and overall biodiversity in the area and restore fluvial connectivity.
This restoration project, initiated in 2023, was led by ANP/WWF in collaboration with SOS Animal (weir owner) and the Santarém Municipal Council (local government). Mr. Goll was invited to design the removal of the concrete weir, including innovative solutions such as the use of live timber crib walls for stream bank stabilization. He also provided consultation to the onsite construction manager during the removal process and conducted a final site walkthrough following construction, offering recommendations to ensure long-term success.
The Perofilho Weir removal, completed in October 2024, restored 2.2 kilometers of the Perofilho Stream—nearly half its total length—reconnecting it with the Tejo River. This comprehensive restoration project addressed sediment management, habitat rehabilitation, and flood risk reduction, resulting in significant improvements to water quality and ecological health. Key species benefiting from these efforts include the Eurasian otter (Lutra lutra) and the Iberian painted frog (Discoglossus galganoi). Notably, it also enabled the first research into fish species inhabiting the stream.
This milestone project not only revitalized a critical aquatic ecosystem, it also established a blueprint for future river restoration efforts in Portugal and beyond.
During Mr. Goll’s visit to Portugal in October 2024, he toured the Perofilho Weir removal site alongside Maria João Costa, Water Coordinator of ANP/WWF. Together, they participated in a live video event hosted by the World Fish Migration Foundation, celebrating the project’s success. Broadcasted on the Dam Removal Europe YouTube channel, the event highlighted the restoration effort’s impact on biodiversity and river connectivity. If you missed the live broadcast, the recording is available online. Watch now:
The Oeiras River in western Algarve winds through rural landscapes, agricultural zones, and small towns before merging with the Arade River. This intermittent Mediterranean stream supports native and endangered species and serves as a habitat for some of Portugal’s most iconic mammals.
Recognizing the river’s ecological significance, the ICNF identified it as a high-priority conservation area with potential for impactful restoration. In collaboration with the company Somincor, ICNF contracted ANP/WWF to evaluate the removal of nine barriers along the river, beginning with the upstream Horta Fialho Weir.
To complete the proposed work, ANP/WWF is undertaking several activities, including feasibility assessments, local community and stakeholder engagement, and public environmental education. ANP/WWF engaged Princeton Hydro to prepare the design and specifications for the Horta Fialho Weir removal and develop concept designs for the eight (8) additional barriers.
In October 2024, Mr. Goll spent a week in the field alongside ANP/WWF, surveying the Oeiras River and its tributaries, documenting blockages and ecosystem conditions, meeting with local dam owners and community members, and gathering field measurements to inform the designs and specifications.
The removal of the Horta Fialho Weir will reconnect 2.34 kilometers of the river and set the stage for removing the eight additional barriers, which would ultimately restore 143.4 kilometers of river connectivity. This ambitious initiative is expected to significantly enhance the river’s ecological health and improve habitats for native and endangered species, including freshwater mussels (Unio tumidiformis, Anodonta anatina, Unio delphinus), and their host fish (Squalius spp.), the migratory European eel (Anguilla anguilla), the Iberian lynx (Lynx pardinus), and the Eurasian otter (Lutra lutra).
Beyond ecological benefits, the project offers a unique opportunity to raise awareness about the advantages of dam removal and the critical importance of biodiversity conservation across Portugal. The European Open Rivers Programme is funding this landmark restoration effort.
Portugal’s ecosystem restoration projects illustrate the impact of international collaboration and knowledge exchange. By removing barriers, reconnecting habitats, and revitalizing ecosystems, these efforts are paving the way for a healthier future for rivers and the communities that depend on them. Through continued partnerships and mutual support, the journey toward sustainable environmental stewardship remains hopeful and promising.
Building on the success of these initiatives, Mr. Goll and the Princeton Hydro team look forward to continuing their work in Portugal and beyond, offering technical expertise in ecosystem restoration and barrier removal to support similar efforts around the world.
This work would not be possible without the dedication of ANP/WWF, the European Open Rivers Programme, the Dam Removal Europe team, The National Authority for Nature and Forests Conservation, Herman Wanningen, and all the local landowners who were committed to the restoration of the Oeiras River. Their commitment to river restoration and biodiversity conservation serves as an inspiration, demonstrating the transformative power of collaboration and shared vision. We encourage you to click the links provided to learn more about these vital organizations.
Princeton Hydro has successfully designed, permitted, and overseen the removal of over 84 dams to date. Mr. Goll holds a B.S. in Civil Engineering from Rutgers University and a Master of Engineering Management from UW–Madison. His knowledge encompasses water resources and geotechnical engineering, including sediment management, stream and river restoration, stormwater management, green infrastructure, freshwater wetland and coastal marsh design, dam design, and dam removal. He is recognized as a distinguished leader in advancing innovative and effective solutions for river restoration.
For the first time in over 200 years, the lower Bushkill Creek is now free-flowing and fully reconnected with the Delaware River and, ultimately, the Atlantic Ocean. This tremendous achievement signals a turning point for the ecological health of the Bushkill Creek watershed, supporting the passage of migratory fish species, bolstering ecologically beneficial freshwater mussel populations, reconnecting river habitats that benefit fish and wildlife, and enhancing water quality across the Delaware River Basin, which provides drinking water to millions of people.
"This significant, yearslong restoration effort exemplifies the power of conservation partnerships to achieve profound ecological impact,” said Princeton Hydro President and Founding Principal Geoffrey M. Goll, PE “The restored Bushkill Creek is more than a reconnected waterway—it is a revitalized natural resource that enhances biodiversity, supports community recreation, and contributes to the local economy in sustainable ways.”
Bushkill Creek begins at the foot of Blue Mountain in Bushkill Township, Pennsylvania, and flows for 22 miles through agricultural and suburban areas, including Easton. The limestone stream supports a thriving wild brown trout population and is designated as a “high-quality, cold-water fishery” cherished by anglers and the local community.
Since 2021, Wildlands Conservancy has led the charge to remove five aging dams along Bushkill Creek. While these structures once served industrial and community functions, they had become barriers to fish migration, disrupted the creek’s natural flow, and contributed to localized flooding and water quality issues. Now, with these obstacles cleared, Bushkill Creek flows freely from its headwaters to its confluence with the Delaware River.
Along the creek, the removal of Dam #2 signifies a momentous occasion in its restoration journey, representing the most recent advancement in dam removal efforts.
Led by the Wildlands Conservancy, the restoration of Bushkill Creek involved more than 20 stakeholders, including the Delaware River Basin Commission, Lafayette College, Pennsylvania Department of Environmental Protection, National Fish and Wildlife Foundation, Pennsylvania Department of Conservation and Natural Resources, and Princeton Hydro.
In a press release from the Wildlands Conservancy, President Christopher Kocher, praised the collaborative effort, stating, “This yearslong effort is a win for clean water for all the communities living in connection with the Bushkill Creek. It’s a wonderful example of the power of partnerships, and what community can do for community when nonprofits, local government, and state and federal agencies pool ideas and resources to invest in our treasured natural areas.”
To celebrate this tremendous accomplishment, Wildlands Conservancy, project partners, funders, and community volunteers gathered on October 15, 2024, at Lafayette College’s Karl Stirner Arts Trail.
The event included a volunteer-powered wildflower planting to complete the restoration work at this site, where Dam #1, formerly owned by Lafayette College, had been removed in 2023 with the support of Princeton Hydro. Spanning 90 feet in length and standing 4 feet high, the dam had severely obstructed fish passage, contributed to local flooding, and impaired water quality over time. The college enthusiastically supported the dam's removal, dedicating substantial resources to see the project to completion.
Wildlands Conservancy, a non-profit land trust based in eastern Pennsylvania, is dedicated to the restoration of degraded stream and wildlife habitats, with a primary focus on the Lehigh Valley and the extensive Lehigh River watershed, which spans 1,345 square miles, eventually merging with the Delaware River. For over a decade, Princeton Hydro has been a steadfast partner to Wildlands Conservancy in their mission, collaborating on multiple dam removal projects in the Delaware River Watershed.
After 129 years, the Paulina Lake Dam in Warren County is in the final stages of demolition. This project, led by The Nature Conservancy's New Jersey Chapter, is hailed by local advocates as a significant environmental victory. The complete removal of the dam, scheduled from July through September 2024, is the second of three phases of river restoration, and signifies a major milestone in the rehabilitation of the Paulins Kill River, New Jersey’s third-largest tributary to the Delaware River.
On November 24, 2023, a crucial step in the restoration journey was taken with the first notching of the Paulina Dam. This initial step set the stage for the next phase of the dam removal, which is now in full swing. The project, a successful collaboration under the leadership of The Nature Conservancy, funded by NJDEP Division of Fish and Wildlife, and designed and implemented by Princeton Hydro and RiverLogic-Renova Joint Venture, respectively, is progressing toward its goal. The third and final phase will occur in 2025 for adaptive management to complete the finishing touches, including the installation of habitat features to further enhance the biodiversity of this river segment.
Click below to watch a new video showcasing the project's progress. The drone footage captures the project team in action, demolishing the dam, removing sediment upriver, and strategically placing rock check dam to control the flow of sediment as the removal process continues.
Blairstown’s original power source for electricity, the Paulina Lake Dam, located in bucolic Warren County, NJ, has long posed challenges to the river’s health and surrounding communities. Originally constructed to produce hydropower, it has not functioned in that capacity for over 50 years. Its removal is crucial not only for mitigating risks to life and property but also for restoring the natural habitat for native species like brook trout and migratory fish.
Located in bucolic Warren County, New Jersey, The Paulina Lake Dam, Blairstown’s original power source for electricity, has long posed challenges to the river’s health and, after the dam ceased its use as a power source, became a financial and safety liability to Blairstown Township. Its removal is crucial not only for mitigating risks to life and property but also for restoring the natural habitat for native species like brook trout and migratory fish.
This initiative aims to:
The removal of the Paulina Lake Dam is part of a larger restoration plan initiated in 2013 by The Nature Conservancy, which includes the removal of multiple dams along the Paulins Kill River, planting thousands of trees in its riparian zone, and restoration of its headwater Hyper Humus, a glacially created peat bog. This comprehensive effort, involving wetland restoration, land protection, and floodplain reforestation, aims to rejuvenate and sustain the river ecosystem.
Princeton Hydro’s President, Geoffrey M. Goll, PE, highlights the broader impact of these efforts: “The removal of Paulina Lake Dam is not just about dismantling a structure and removing a safety hazard, but paving the way for a renewed riverine landscape, where the flow of life returns to its natural course.”
As we celebrate this major milestone, we look forward to witnessing the continued transformation of the Paulins Kill. This project stands as a testament to the power of collaboration, environmental stewardship, and the unwavering dedication of communities and organizations committed to preserving and restoring our natural landscapes.
Stay tuned for more updates as we continue this exciting journey towards a restored and thriving river ecosystem this fall, and then the finishing touches in 2025! Click here to learn more about the Paulina Lake Dam removal and the broader restoration efforts.
The removal of Bushkill Creek Dam #2 is now underway, marking yet another remarkable milestone in the rejuvenation of this treasured limestone stream. This achievement comes on the heels of four successfully completed dam removals since 2021, highlighting the swift progress in the revitalization efforts for Bushkill Creek.
This latest endeavor holds immense significance in facilitating the passage of migratory fish species, such as alewife and American shad, to vital upstream spawning grounds. It contributes to the recovery of ecologically-beneficial freshwater mussels and the bolstering of populations of trout and other resident fish species. And, it marks another important step in returning Bushkill Creek to its natural, free-flowing state.
During a recent site visit, Princeton Hydro President and Founding Principal Geoffrey M. Goll, P.E. took a moment to reflect on the years of hard work that have culminated in this significant milestone. Watch now:
In 2022, Wildlands Conservancy enlisted the expertise of Princeton Hydro to embark on a mission to remove four dams along Bushkill Creek. The successful removal of the Crayola Dam, also known as Dam #4, marked the beginning of this transformative journey. Subsequently, in 2023, Dams #1 and #3 were dismantled. Now, we celebrate the commencement of the removal of Dam #2.
Bushkill Creek flows 22-miles through agricultural and suburban landscape before converging with the Delaware River. Dam #2, situated upstream from the Creek’s confluence with the Delaware River, obstructed fish passage, exacerbated local flooding, and degraded water quality, much like its counterparts. Its removal represents a significant leap forward in the restoration of Bushkill Creek's ecological health.
The ongoing restoration of Bushkill Creek is a testament to the dedication of over 20 stakeholders, including, but not limited to, Wildlands Conservancy, the Delaware River Basin Commission, Lafayette College, Pennsylvania Department of Environmental Protection, National Fish and Wildlife Foundation, Pennsylvania Department of Conservation and Natural Resources, and Princeton Hydro.
Funding for the projects has stemmed from various sources, including a settlement following a fly ash spill from the Martins Creek Power Plant in 2005. This settlement, coupled with contributions from organizations like NFWF’s Delaware Watershed Conservation Fund and Northampton County’s Livable Landscapes program, propelled the initiative forward.
As we celebrate the start of removing Bushkill Creek Dam #2, we anticipate continued progress in the revitalization of this vital waterway. Each dam removed brings us closer to realizing the vision of a thriving, free-flowing Bushkill Creek, benefitting both the environment and local communities.
Wildlands Conservancy, a non-profit land trust based in eastern Pennsylvania, is dedicated to the restoration of degraded stream and wildlife habitats, with a primary focus on the Lehigh Valley and the extensive Lehigh River watershed. Spanning 1,345 square miles, this watershed eventually merges with the Delaware River.
For over a decade, Princeton Hydro has been a steadfast partner to Wildlands Conservancy in their mission, collaborating on multiple dam removal projects in the Lehigh River Valley. With expertise in design, permitting, and oversight, Princeton Hydro has played a pivotal role in the removal of over 80 small and large dams/barriers across the Northeast.
To explore Princeton Hydro's comprehensive fish passage and dam removal engineering services, click here. For more information about Wildlands Conservancy and their conservation efforts, click here.
Princeton Hydro's President and Founding Principal, Geoffrey M. Goll, PE, recently participated in the prestigious Free Flow 2024 conference in Groningen, The Netherlands. This international event, focused on protecting and restoring free-flowing rivers, gathered policy makers, river managers, ecologists, researchers, students, and industry professionals from around the globe. With 130 speakers spread across 27 sessions, the conference delved into crucial topics like dam removal, fish passage, and the ecology of free-flowing rivers.
Free Flow 2024, organized by the World Fish Migration Foundation and the Institute of Fisheries Management, highlighted the urgent need for river restoration to achieve the EU 2030 Biodiversity goal of freeing up 25,000 km (15,534 miles) of rivers. The conference aimed to connect practitioners and scientists, promote knowledge sharing, and spur the implementation of innovative river restoration projects.
Geoff participated in an expert panel for the "Prioritizing Rivers and Dams for Restoration" workshop. The workshop, moderated by Joshua Royte of The Nature Conservancy and Dr. Ruben van Treeck of World Wide Fund For Nature Germany, also included esteemed panelists Dr. Carlos Garcia De Leaniz of Swansea University, Dr. Jesse O'Hanley of the University of Kent, and Dr. Paulo Branco of the University of Lisbon. The discussion focused on the most efficient means and tools for prioritizing the removal of stream and river barriers in watersheds, considering both micro- and macroscale approaches. Geoff's contribution centered on the confounding and feasibility issues of individual barriers that could influence the overall prioritization process.
Geoff also led a presentation titled "Dam Removal is not just about Dam Removal," Geoff emphasized the multifaceted benefits of dam removal beyond fish passage restoration. He argued that successful dam removal projects hinge on understanding and balancing the diverse values of stakeholders, managing sediment, protecting infrastructure, and recognizing the opportunities for restoring natural capital.
During the presentation, Geoff highlighted that while many dams no longer serve their original functions, some remain integral to the communities around them, often holding deep emotional significance. His presentation illustrated the wide-ranging restoration possibilities and community benefits of dam removal, including:
Additionally, Geoff's presentation reviewed the values of existing dams and their impoundments, the institutional and physical challenges of removal, and showcased successful examples of dam removal projects in the northeastern United States, providing valuable insights for European ecosystem restoration efforts.
Princeton Hydro was also proud to sponsor the Dam Removal & Small Barriers portion of the education program.
In advance of his panel presentation, Geoff created and distributed a poll using Mentimeter to gather insights from conference attendees. This interactive approach allowed participants to share their thoughts and experiences ahead of the workshop, fostering a more engaging and tailored discussion. The questions posed in the poll were designed to capture a range of perspectives on barrier removal, a key topic at the conference.
The responses collected provided valuable input that helped shape the dialogue during Geoff's presentation. Here are the visual results of the poll:
The creative atmosphere of the Oosterpoort venue in Groningen fostered dynamic exchanges of ideas and solutions. The conference featured over 100 presentations, divided into parallel sessions, providing a comprehensive exploration of river restoration topics, including: Ecology and hydromorphology of free-flowing rivers; freshwater fish and fisheries; hydropower development vs. free-flowing rivers; policies for free-flowing rivers; river restoration tools and projects; cultural and socio-economic aspects of free-flowing rivers; nature-based solutions; and dam removal and fish passage projects.
The conference included various networking opportunities, such as a cocktail reception on the first evening and a conference dinner on the second, allowing attendees to connect and discuss their work in a more relaxed setting. Throughout the conference, poster sessions showcased ongoing research, and an exhibitor marketplace provided an additional platform for participants to engage with the latest innovations and tools in river restoration.
Participants also had the opportunity to join one of five field trips organized in cooperation with the Wadden Sea Swimway project. These excursions provided a hands-on look at various river restoration and fish passage projects. For instance, one field trip followed the journey of a sea trout as it navigates to its ancestral spawning grounds, offering participants an immersive experience in understanding the challenges and successes of fish migration.
The Free Flow 2024 conference underscored the critical importance of river restoration in the face of climate change and biodiversity loss. By bringing together leading experts and fostering a collaborative environment, the event contributed significantly to the advancement of knowledge and the implementation of effective river restoration strategies.
"Participating in the Free Flow 2024 Conference was an incredible opportunity to collaborate with global experts dedicated to river restoration," said Geoff. "Through insightful discussions and educational sessions, we exchanged valuable knowledge and experiences, strengthening our shared commitment to protecting and restoring free-flowing rivers. It is encouraging to witness the dedication and innovative solutions being applied globally.”
Click here to learn more about Free Flow 2024, view presentation abstracts, the complete agenda, and more photos from the conference.
Princeton Hydro has successfully designed, permitted, and overseen the removal of over 84 dams to date. Geoff holds a B.S. in Civil Engineering from Rutgers University and a Master of Engineering Management from UW–Madison. His knowledge encompasses water resources and geotechnical engineering, including sediment management, stream and river restoration, stormwater management, green infrastructure, freshwater wetland and coastal marsh design, dam design, and dam removal. Geoff’s is recognized as a distinguished leader in advancing innovative and effective solutions for dam removal and river restoration. To read about a recent dam removal project that Geoff spearheaded with The Nature Conservancy in New Jersey, click here.
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