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.
WP_Query Object ( [query] => Array ( [services] => erosion-and-sedimentation-assessment ) [query_vars] => Array ( [services] => erosion-and-sedimentation-assessment [error] => [m] => [p] => 0 [post_parent] => [subpost] => [subpost_id] => [attachment] => [attachment_id] => 0 [name] => [pagename] => [page_id] => 0 [second] => [minute] => [hour] => [day] => 0 [monthnum] => 0 [year] => 0 [w] => 0 [category_name] => [tag] => [cat] => [tag_id] => [author] => [author_name] => [feed] => [tb] => [paged] => 1 [meta_key] => [meta_value] => [preview] => [s] => [sentence] => [title] => [fields] => all [menu_order] => [embed] => [category__in] => Array ( ) [category__not_in] => Array ( ) [category__and] => Array ( ) [post__in] => Array ( ) [post__not_in] => Array ( ) [post_name__in] => Array ( ) [tag__in] => Array ( ) [tag__not_in] => Array ( ) [tag__and] => Array ( ) [tag_slug__in] => Array ( ) [tag_slug__and] => Array ( ) [post_parent__in] => Array ( ) [post_parent__not_in] => Array ( ) [author__in] => Array ( ) [author__not_in] => Array ( ) [search_columns] => Array ( ) [ignore_sticky_posts] => [suppress_filters] => [cache_results] => 1 [update_post_term_cache] => 1 [update_menu_item_cache] => [lazy_load_term_meta] => 1 [update_post_meta_cache] => 1 [post_type] => [posts_per_page] => 10 [nopaging] => [comments_per_page] => 5 [no_found_rows] => [taxonomy] => services [term] => erosion-and-sedimentation-assessment [order] => DESC ) [tax_query] => WP_Tax_Query Object ( [queries] => Array ( [0] => Array ( [taxonomy] => services [terms] => Array ( [0] => erosion-and-sedimentation-assessment ) [field] => slug [operator] => IN [include_children] => 1 ) ) [relation] => AND [table_aliases:protected] => Array ( [0] => ph_term_relationships ) [queried_terms] => Array ( [services] => Array ( [terms] => Array ( [0] => erosion-and-sedimentation-assessment ) [field] => slug ) ) [primary_table] => ph_posts [primary_id_column] => ID ) [meta_query] => WP_Meta_Query Object ( [queries] => Array ( ) [relation] => [meta_table] => [meta_id_column] => [primary_table] => [primary_id_column] => [table_aliases:protected] => Array ( ) [clauses:protected] => Array ( ) [has_or_relation:protected] => ) [date_query] => [queried_object] => WP_Term Object ( [term_id] => 1451 [name] => Erosion and Sedimentation Assessment [slug] => erosion-and-sedimentation-assessment [term_group] => 0 [term_taxonomy_id] => 1451 [taxonomy] => services [description] => [parent] => 1263 [count] => 30 [filter] => raw [term_order] => 8 ) [queried_object_id] => 1451 [request] => SELECT SQL_CALC_FOUND_ROWS ph_posts.ID FROM ph_posts LEFT JOIN ph_term_relationships ON (ph_posts.ID = ph_term_relationships.object_id) WHERE 1=1 AND ( ph_term_relationships.term_taxonomy_id IN (1451) ) AND ((ph_posts.post_type = 'project' AND (ph_posts.post_status = 'publish' OR ph_posts.post_status = 'acf-disabled'))) GROUP BY ph_posts.ID ORDER BY ph_posts.menu_order, ph_posts.post_date DESC LIMIT 0, 10 [posts] => Array ( [0] => WP_Post Object ( [ID] => 18795 [post_author] => 1 [post_date] => 2025-11-05 17:12:57 [post_date_gmt] => 2025-11-05 17:12:57 [post_content] => Princeton Hydro and our project partner, the American Littoral Society, developed living shoreline designs for Nyack Beach State Park. The project goal was to create shorelines resilient to extreme storms and increase resilience to damages linked to climate change while enhancing ecological values and preserving public use of the site. The final selected shoreline designs were consistent with the Master Plan for the Nyack Beach State Park and promoted goals of the 2010-2014 Hudson River Estuary Action Agenda. With these goals and objectives in mind, the Princeton Hydro team worked closely with the Hudson River Estuary Program (HREP), Nyack Beach State Park staff, and the other project stakeholders to generate ecologically-enhanced, engineered shoreline treatments that resist erosion, enhance the recreational use of the site, and improve habitat for fish and wildlife species. The Princeton Hydro team consulted state and federal regulations governing waterfront projects and took into consideration guidance offered directly by New York State Department of Environmental Conservation (NYSDEC) during the early stages of design development. A “tread lightly” approach was taken, promoting nature-based solutions. Satisfactory existing elements of the site, including post-Hurricane-Sandy repairs to the park and its shoreline, were enhanced rather than redone. [gallery link="none" columns="2" size="medium" ids="18794,18793"] A large portion of the selected design included access to the river and the park’s intertidal, nearshore areas. Thus, the project approach would need to be sensitive to park use by visitors. At the same time, as directed by the Nyack Beach State Park staff, our designs were designed to minimize the maintenance responsibilities of park staff. [post_title] => Sustainable Shoreline at Nyack Beach State Park [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => sustainable-shoreline-at-nyack-beach-state-park [to_ping] => [pinged] => [post_modified] => 2025-12-08 21:44:20 [post_modified_gmt] => 2025-12-08 21:44:20 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=18795 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [1] => WP_Post Object ( [ID] => 18610 [post_author] => 1 [post_date] => 2025-11-05 14:49:39 [post_date_gmt] => 2025-11-05 14:49:39 [post_content] => The Anchor QEA–Princeton Hydro team was selected by Audubon New York (and its partners Save the Sound and New York State Parks) to design the restoration and enhancement of an approximately 400-acre tidal marsh on the north-central coast of Long Island. The marsh has experienced restricted tidal flow since an earthen berm was breached in 2012 during Superstorm Sandy. The restricted tidal flow led to marsh degradation, which converted portions of the former salt marsh to brackish and freshwater marsh. The lack of tidal flushing also enabled invasive Phragmites australis to establish and spread within the marsh system. Design goals included:
Princeton Hydro and our project partner, the American Littoral Society, developed living shoreline designs for Nyack Beach State Park. The project goal was to create shorelines resilient to extreme storms and increase resilience to damages linked to climate change while enhancing ecological values and preserving public use of the site.
The final selected shoreline designs were consistent with the Master Plan for the Nyack Beach State Park and promoted goals of the 2010-2014 Hudson River Estuary Action Agenda. With these goals and objectives in mind, the Princeton Hydro team worked closely with the Hudson River Estuary Program (HREP), Nyack Beach State Park staff, and the other project stakeholders to generate ecologically-enhanced, engineered shoreline treatments that resist erosion, enhance the recreational use of the site, and improve habitat for fish and wildlife species.
The Princeton Hydro team consulted state and federal regulations governing waterfront projects and took into consideration guidance offered directly by New York State Department of Environmental Conservation (NYSDEC) during the early stages of design development. A “tread lightly” approach was taken, promoting nature-based solutions. Satisfactory existing elements of the site, including post-Hurricane-Sandy repairs to the park and its shoreline, were enhanced rather than redone.
A large portion of the selected design included access to the river and the park’s intertidal, nearshore areas. Thus, the project approach would need to be sensitive to park use by visitors. At the same time, as directed by the Nyack Beach State Park staff, our designs were designed to minimize the maintenance responsibilities of park staff.
The Anchor QEA–Princeton Hydro team was selected by Audubon New York (and its partners Save the Sound and New York State Parks) to design the restoration and enhancement of an approximately 400-acre tidal marsh on the north-central coast of Long Island. The marsh has experienced restricted tidal flow since an earthen berm was breached in 2012 during Superstorm Sandy. The restricted tidal flow led to marsh degradation, which converted portions of the former salt marsh to brackish and freshwater marsh. The lack of tidal flushing also enabled invasive Phragmites australis to establish and spread within the marsh system.
The Anchor QEA–Princeton Hydro team developed 60% Designs, including design drawings, a cost estimate, a long-term management plan, and a QAPP. The project design includes dredging approximately 15,000 cubic yards of material from Sunken Meadow Creek and thin layer placement of dredged material onto adjacent marsh cells to develop low and high marsh footprints; treating approximately 20 acres of Phragmites australis and phased replanting the areas with native species; creating approximately 2,000 linear feet of channels in the marsh and improving approximately 8,500 linear feet of existing channels to enhance drainage and tidal flushing; creating tidal pools and installing anchored rootwads to promote habitat diversity; modifying existing culverts within the primary flow channel through the marsh; and planting within the high and low salt marsh footprints.
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 Ousatonic Fish and Game Protective Association, Inc., in partnership with the Connecticut Department of Energy and Environmental Protection’s Inland Fisheries Division, sought to remove the Papermill Pond Dam on the East Aspetuck River to restore fish habitat formerly exceptional in quality for trout, facilitate fish passage through the site, and improve accessibility and functionality for people to engage in outdoor activities at the site in order to foster deeper stewardship ethic for the watershed.
The Papermill Pond Dam, located in New Milford, is an embankment dam situated on the East Aspetuck River. It is located 2.9 miles upstream of the confluence with the Housatonic River and is the first barrier on the East Aspetuck River. The spillway is concrete capped with masonry core. It has an approximate structural height of 11 feet and length of 75 feet.
The following alternatives were analyzed: 1) no action; 2) fishway bypass channel around dam; 3) technical fishway at dam; 4) dam lowering with fishway at dam; 5) river bypass and off-line pond; and, 6) full removal. Conceptual designs were developed for each alternative. Each alternative was analyzed and rated numerically relative to twelve categories: river morphology, aquatic resources (fisheries, macroinvertebrates, water quality), recreation, historic resources, flooding, relative liability, relative short-term costs, relative long-term costs, availability of funds, and anticipated permitability. Dam removal ranked as the most feasible alternative, but dam repair stood out as the best option for maintaining the existing ease of recreational access. That alternative necessitated dam repair, ongoing maintenance and inspection, both short-term and long-term sediment dredging, and construction of a fish bypass channel. The Association considered the alternatives and decided to pursue full dam removal.
Based on negotiations with CTDEEP that considered impacts to downstream habitats and other applicable regulations, the resulting recommendation was to remove a portion of the impounded sediment prior to passive release of the remaining impounded sediment, regardless of potential contamination. This minimized transitory sediment deposition in downstream habitats, thereby reducing the short-term impacts of the project. Thus, sediment proximal to the dam is proposed to be excavated and permanently deposited in upland areas onsite.
The dam was successfully removed in 2019 under supervision of CTDEEP Fisheries Division and Princeton Hydro.
The Martin Dam was constructed on an active farm in 1961 as part of USDA’s sustainable farms pond construction initiative. Martin Dam’s robust 4,000 cubic yards of placed dam material resulted in the impoundment of only 3.5 acres of surface water. Several years ago, during the removal of a beaver dam that was obstructing the dam outlet, the riser structure was inadvertently destroyed, and a large part of the earthen dam collapsed. Due to the damage, the dam was put under an enforcement action from the Maryland Department of the Environment (MDE) Dam Safety Program. Site investigations showed an outlet culvert in total disrepair and severe erosion of the dam and downstream areas.
Fearing the risk to property and life from a catastrophic dam failure, GreenTrust Alliance, in partnership with Princeton Hydro, were enlisted to design, develop, and enact an emergency dam breach. The earthen dam was approximately 20 feet in height and 490 feet in length, with an impoundment of approximately 3.48 acres. The contributing drainage area was approximately 0.25 square miles (160 acres) of low density residential land use and the primary inflowing channel, Overshot Branch, was intermittent or ephemeral. The assessment and design involved probing within the impoundment, which revealed water depths averaging 4.7 feet, with a maximum of 7.5 feet, and impounded sediment depths averaging 1.0 foot, with a maximum of 3.0 feet.
Princeton Hydro prepared a 35% design plan for the earthen dam removal, and this plan was subsequently approved by MDE Dam Safety with an emergency permit, forgoing the typical months-long design and review process. The dam breach was implemented in late 2018.
After the dam breach, Princeton Hydro completed a hydrologic and hydraulic assessment. Pre- and post-breach conditions were modeled to determine the potential increase in flood elevations to downstream properties. In addition, a dam failure was also modeled to assess the potential risks should the dam have failed. In comparing the pre-and post-breach scenarios, 100-year flood elevations increased between 0.01 and 0.29 feet for approximately 1 mile downstream of the pond. The floodplain valley for this stream was relatively narrow which means any increases in discharge translated to larger increases on peak flood elevations compared to the total width of the floodplain. However, the narrow floodplain also acted a barrier, ensuring that flooding was mostly contained to the area around the stream itself. No additional structures were inundated as a result of the breach.
Princeton Hydro, along with GreenVest and Green Trust Alliance, developed a design that enhanced in-stream habitat of the downstream reach, and allowed for passive wetland conversion and restoration of the former impoundment.
Princeton Hydro and BRS, Inc. were contracted by the Cities of Trenton and Salem to perform climate change-related hazard vulnerability assessments to inform municipal resilience action plans.
The work was completed as part of the Resilient NJ Program, an assistance program run by the NJDEP Bureau of Climate Resilience Planning. The program supports local and regional climate resilience planning by bringing together planners, engineers, designers, and other experts to address flood- and climate-related hazards. The Cities of Trenton and Salem, like many across the region, already experience climate related hazards such as extreme heat and flooding which disrupts traffic patterns, impacts infrastructure, damages property, and puts lives at risk. These climate-related hazards are expected to worsen over the next century and beyond due to climate change.
In order to prepare for and adapt to climate-related hazards, our team worked to map extreme heat and flooding hazards across these cities under both current climate conditions and future projections. We then assessed the geographic distribution of these hazards to identify at-risk populations and city resources, such as critical infrastructure, community assets, cultural and historic resources, and land developments. These assessments will be used to develop resilience action plans, which will guide future climate hazard policies, planning, and projects in Trenton and Salem.
A key component of our climate hazard vulnerability assessments was to not only provide information needed for planning and decision-making, but to also provide information to the general public. Princeton Hydro and BRS facilitated several public information sessions. The Princeton Hydro-BRS Team provided a primer on climate hazards and presented the vulnerability assessment findings along with a Q&A session. This process invited public feedback and maximized public participation.
Princeton Hydro was on the team to study the Bronx River Double Dam for New York City Parks (the dam owner). The project goal was to present an economically, environmentally, and socially sustainable long-term fish-passage solution for the Bronx River Double Dam.
The culmination of the project was a fish passage Alternatives Analysis for the dam site, where the cost and benefits of various long-term solutions for the project site were assessed, including dam removal and an engineered fishway. To inform the Alternatives Analysis, Princeton Hydro first studied the feasibility of the removal of the Bronx River Double Dam.
To inform the dam removal feasibility study and a conceptual dam removal design, Princeton Hydro supplemented data from a previous technical fishway design with data collected from additional field investigations. Princeton Hydro led the field collection effort, including sediment sampling, sediment probing, and a bathymetric survey to shed light on the impounded sediment concerns. Field investigations also included an investigation on the infrastructure, an updated topographic survey, and a seismic refraction survey to understand the potential for underlying bedrock to inform a conceptual design for dam removal.
Based on the data reviewed, Princeton Hydro concluded that dam removal is feasible and that its removal would 1) Restore the Bronx River to its historical flowpath, 2) Likely restore transparent fish passage at the site, and 3) Not impact infrastructure.
In comparing the dam removal alternative to the engineering fishway, the dam removal would provide a greater ecological benefit, while also reducing long term liabilities related to dam failure and costs associated with dam maintenance and inspection. Despite uncertainty associated with the dam removal alternative at this stage in the concept design, it is expected the upfront construction cost of the dam removal would be higher than the engineering fishway alternative.
The feasibility study and alternatives analysis set the stage for the US Army Corps of Engineers to further study fish passage at the Bronx River Double Dam.
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.
Mercer County is currently conducting maintenance dredging for a portion of the impoundment (Miry Run) behind Dam 21. The focus of the dredging is to remove sediment in the vicinity of the water trail proposed as set forth in the January 2020 Master Plan for the Miry Run Ponds Park. Initially it was assumed, and was later confirmed, the material to be dredged was clean (i.e. below NJDEP residential reuse threshold) and that the dredged material would be placed on the adjacent farm fields and disked into the soil. The project was based on the Dredging Concept Plan that initially identified the areas proposed for dredging and thin layer application. If the dredged sediments from the project had been determined to be above NJDEP’s threshold for the intended use in the placement areas, it would have been dewatered onsite and disposed of at a regulated facility.
Based on an evaluation of the completed bathymetric survey, which was completed as part of the Master Plan, and the location of the water trail, Princeton Hydro identified three primary areas where the maintenance dredging will be focused.
Dredging Area 1 is in the main body of the lake just downstream of Line Road and would generate approximately 34,000 cubic yards of dredged material.
Dredging Area 2 is in the northeast cove, just north of Dredging Area 1. Dredging Area 2 has approximately 4,900 cubic yards of accumulated sediment.
Dredging Area 3, the northwestern cove, would require the removal of approximately 7,300 cubic yards of accumulated sediment. Total anticipated dredging volume is roughly 46,200 cubic yards.
The final project scope included (1) a sediment sampling plan, (2) sample collection and laboratory analysis, (3) engineering plan preparation, (4) preparation and submission of all NJDEP regulatory permitting materials, (5) preparation of the technical specification, (6) bid administration, and (7) construction administration and observation services.
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.
Your Full Name * Phone Number * Your Email * Organization Address Message *
By EmailBy Phone
Submit
Δ
Couldn’t find a match? Check back often as we post new positions throughout the year.
PRINCETON HYDRO
PRINCETON HYDRO