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WP_Query Object ( [query] => Array ( [location] => maryland ) [query_vars] => Array ( [location] => maryland [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] => location [term] => maryland [order] => DESC ) [tax_query] => WP_Tax_Query Object ( [queries] => Array ( [0] => Array ( [taxonomy] => location [terms] => Array ( [0] => maryland ) [field] => slug [operator] => IN [include_children] => 1 ) ) [relation] => AND [table_aliases:protected] => Array ( [0] => ph_term_relationships ) [queried_terms] => Array ( [location] => Array ( [terms] => Array ( [0] => maryland ) [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] => 7 [name] => Maryland [slug] => maryland [term_group] => 0 [term_taxonomy_id] => 7 [taxonomy] => location [description] => [parent] => 0 [count] => 6 [filter] => raw [term_order] => 0 ) [queried_object_id] => 7 [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 (7) ) 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] => 15951 [post_author] => 1 [post_date] => 2024-11-07 18:54:42 [post_date_gmt] => 2024-11-07 18:54:42 [post_content] => The Martin Dam was constructed on an active farm in 1961 as part of USDA’s sustainable farms pond construction initiative. Martin Dam’s robust 4,000 cubic yards of placed dam material resulted in the impoundment of only 3.5 acres of surface water. Several years ago, during the removal of a beaver dam that was obstructing the dam outlet, the riser structure was inadvertently destroyed, and a large part of the earthen dam collapsed. Due to the damage, the dam was put under an enforcement action from the Maryland Department of the Environment (MDE) Dam Safety Program. Site investigations showed an outlet culvert in total disrepair and severe erosion of the dam and downstream areas. Fearing the risk to property and life from a catastrophic dam failure, GreenTrust Alliance, in partnership with Princeton Hydro, were enlisted to design, develop, and enact an emergency dam breach. The earthen dam was approximately 20 feet in height and 490 feet in length, with an impoundment of approximately 3.48 acres. The contributing drainage area was approximately 0.25 square miles (160 acres) of low density residential land use and the primary inflowing channel, Overshot Branch, was intermittent or ephemeral. The assessment and design involved probing within the impoundment, which revealed water depths averaging 4.7 feet, with a maximum of 7.5 feet, and impounded sediment depths averaging 1.0 foot, with a maximum of 3.0 feet. Princeton Hydro prepared a 35% design plan for the earthen dam removal, and this plan was subsequently approved by MDE Dam Safety with an emergency permit, forgoing the typical months-long design and review process. The dam breach was implemented in late 2018. After the dam breach, Princeton Hydro completed a hydrologic and hydraulic assessment. Pre- and post-breach conditions were modeled to determine the potential increase in flood elevations to downstream properties. In addition, a dam failure was also modeled to assess the potential risks should the dam have failed. In comparing the pre-and post-breach scenarios, 100-year flood elevations increased between 0.01 and 0.29 feet for approximately 1 mile downstream of the pond. The floodplain valley for this stream was relatively narrow which means any increases in discharge translated to larger increases on peak flood elevations compared to the total width of the floodplain. However, the narrow floodplain also acted a barrier, ensuring that flooding was mostly contained to the area around the stream itself. No additional structures were inundated as a result of the breach. Princeton Hydro, along with GreenVest and Green Trust Alliance, developed a design that enhanced in-stream habitat of the downstream reach, and allowed for passive wetland conversion and restoration of the former impoundment. [post_title] => Martin Farm Pond Emergency Dam Breach & Dam Removal [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => martin-farm-pond-emergency-dam-breach-dam-removal [to_ping] => [pinged] => [post_modified] => 2024-11-08 19:01:34 [post_modified_gmt] => 2024-11-08 19:01:34 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=15951 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [1] => WP_Post Object ( [ID] => 11862 [post_author] => 1 [post_date] => 2022-11-16 15:11:43 [post_date_gmt] => 2022-11-16 15:11:43 [post_content] => As part of New Jersey Audubon Society’s Coastal Impoundment Vulnerability and Resilience Project, Princeton Hydro was contracted to inspect and analyze coastal impoundments along the East Coast. Coastal impoundments allow for the active management of water levels, therefore creating a unique habitat that can influence a diversity of bird populations. The ability to maximize the ecological value of these relatively small impoundment areas to the benefit of numerous species is remarkable. Ranging from coastal areas of Massachusets to Virginia, Princeton Hydro conducted visual engineering inpsections and vulnerability assessments for fourteen impoundment clusters: -Parker River National Wildlife Refuge, MA -Jamaica Bay Wildlife Refuge, NY -Supawna Meadows National Wildlife Refuge, NJ -Edwin B. Forsythe National Wildlife Refuge, NJ -Kingsland Impoundment, NJ -Heislerville Wildlife Management Area, NJ -John Heinz National Wildlife Refuge, PA -Thousand Acre Marsh, DE -Prime Hook, DE -Deal Island Wildlife Management Area, MD -Fairmount Wildlife Management Area, MD -Hog Island Wildlife Management Area, VA -Princess Anne, VA -Doe Creek Wildlife Management Area, VA The engineering team specifically looked for evidence of erosion, overtopping and other conditions that might compromise the stability of the embankments. First, the waterward area was observed to determine the relative protection that may or may not be provided by any existing marsh area or artificial structures. Second, the area inland from the impoundments was observed to determine if the impoundment was potentially providing any storm surge or energy dissipation services for inland structures which might include homes, businesses, roadways, utilities or other structures. Supplementing the desktop GIS analysis, the in-field inspection data provided detailed information on the structural integrity and vulnerability of the embankments, which provided valuable insight for management of the impoundments. [gallery columns="2" link="none" ids="11864,11863"] The findings of the inspections and GIS site evaluations were presented to impoundment operators from across the Mid-Atlantic region. The presentation provided the operators with knowledge which will help them improve the operations of coastal impoundments and increase the resiliency of the structures they manage. [post_title] => Coastal Impoundment Vulnerability and Resilience Project [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => coastal-impoundment-vulnerability-and-resilience-project [to_ping] => [pinged] => [post_modified] => 2024-01-19 01:35:12 [post_modified_gmt] => 2024-01-19 01:35:12 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=11862 [menu_order] => 28 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [2] => WP_Post Object ( [ID] => 11305 [post_author] => 1 [post_date] => 2022-08-24 15:07:29 [post_date_gmt] => 2022-08-24 15:07:29 [post_content] => The City of Annapolis collaborated with Princeton Hydro to achieve compliance with its National Pollutant Discharge Elimination System (NPDES) General Permit for Discharges from Small Municipal Separate Storm Sewer Systems (MS4). The project began with mapping the storm sewer system, focusing on the subwatershed with the highest percentage of impervious surfaces. Using GPS equipment and GIS software, the team mapped the existing storm sewer infrastructure, inspected outfalls for potential illicit discharges, and traced any detected sources of contamination. During these inspections, the team identified and verified both mapped and previously undocumented storm sewer inlets, outlets, and manholes. The team also assessed the condition of each structure, collecting data on internal connections, including type, size, direction, and material. All collected data was integrated into a GIS-based database, providing the City with a comprehensive and actionable map of its storm sewer network. Princeton Hydro has also prepared the Standard Operating Procedures manual for this work and helped to prepare the City’s Good Housekeeping and Pollution Prevention Plans for City-owned facilities that discharge stormwater. Future work for the City will include completing an inventory and map of the remaining subwatersheds, continuing to inspect outfalls and identify Illicit Discharges, and developing new and innovative ways for the City to treat existing stormwater. [gallery link="none" columns="2" ids="11246,11245"] [post_title] => City of Annapolis Stormwater Mapping, Inventory, and Assessment for MS4 Compliance [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => city-of-annapolis-stormwater-mapping-inventory-and-assessment-for-ms4-compliance [to_ping] => [pinged] => [post_modified] => 2025-03-07 12:51:09 [post_modified_gmt] => 2025-03-07 12:51:09 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=11305 [menu_order] => 50 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [3] => WP_Post Object ( [ID] => 8024 [post_author] => 1 [post_date] => 2021-04-28 18:48:03 [post_date_gmt] => 2021-04-28 18:48:03 [post_content] => The USACE Baltimore District hired Princeton Hydro and GreenVest to conduct a mitigation project at Piscataway Creek in Prince Georege’s County, Maryland. This project involved a mitigation site search, preliminary investigation, development of Phase I & II Wetland Mitigation Plans, a wetland delineation, development of an Evaluation of Planned Wetlands analysis, a Threatened and Endangered Species Assessment, a Cultural Resources Investigation, a hydrological and geotechnical evaluation of the site, development of a topographic and boundary survey, and a fixed price turnkey mitigation. Our team was responsible for developing designs and specifications for the ecosystem restoration and mitigation aspects of the project, including but not limited to establishing appropriate design elevations for proposed vegetation communities, plant species selection, construction scheduling, sequencing and post-construction monitoring plans, and using USACE approved CADD and design software. The wetland mitigation is distributed across eight locations on the site. Wetland hydrology leverages the extensive drainage area tributary to the mitigation site inclusive of surface and groundwater resources. The mitigation site generated 12.5 non-tidal wetland mitigation units to offset 11.42 acres of permanent non-tidal wetland impacts. The mitigation project included the preservation of about 50 acres of high quality, non-tidal wetlands, the creation of 9 acres of non-tidal wetlands, and the restoration of 1 acre of non-tidal wetlands— for a total of about 62 acres of restored, preserved, and fully integrated non-tidal wetlands in the headwaters of Piscataway Creek. [post_title] => Piscataway Creek Mitigation for Joint Base Andrews [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => piscataway-creek-mitigation-for-joint-base-andrews [to_ping] => [pinged] => [post_modified] => 2024-07-11 14:54:13 [post_modified_gmt] => 2024-07-11 14:54:13 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=8024 [menu_order] => 80 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [4] => WP_Post Object ( [ID] => 7889 [post_author] => 1 [post_date] => 2021-04-20 20:09:24 [post_date_gmt] => 2021-04-20 20:09:24 [post_content] => Princeton Hydro and GV-Petro Joint Venture are restoring 41,000 linear feet of urban stream using nature-based design techniques within a highly urbanized watershed. Prince George’s County borders Washington, DC to the east, and is the second-most populous county in Maryland. Working with Prince George’s County Department of the Environment and coordinating with the Maryland-National Capital Parks and Planning Commission, this full-delivery project is designed to meet the County’s Watershed Implementation Plan (WIP) and its Municipal Separate Stormwater System (MS4) and TMDL requirements. This stream restoration project was identified as a priority due to the significant levels of channel incision and the severity of erosion and its impacts on surrounding neighborhoods. Additionally, the project’s proximity to the headwater reaches located on Joint Base Andrews (JBA), and the ability to improve water quality and wildlife habitat made this project a high priority. The design for the stream and all the tributaries within the project area will restore the channels and floodplains to naturally stable forms. During the preliminary assessment of onsite conditions, the stream and tributaries within the restoration area were classified using geomorphic assessments and hydrologic and hydraulic analysis. Once the stream types and conditions were identified, a series of restoration approaches such as floodplain creation, bank stabilization using natural materials and plantings, re-aligning straightened stream channels to have a more natural sinuosity, regenerative stream design and natural material grade control structures were used to reduce channel flow velocities and shear stress for flows greater than bankfull, reduce bank erosion and maintain bank stability, treat and attenuate stormwater flows, stabilization of outfalls and the receiving stream channels, and stabilize vertically unstable channels. The project area contained various subsurface utilities, including sanitary sewer along the entire reach, and fiber-optics and natural gas lines across the corridor. The stream restoration project will improve hydraulics, geomorphology, physicochemical, and biological stream functions through bank stabilization. It will also increase floodplain connectivity, improve bedform diversity, restore riparian buffers, and protect public subsurface utilities. In addition to water quality benefits, this project will preserve and enhance the forested floodplain and provide ecological uplift throughout the entire stream corridor. Princeton Hydro is currently (2020) providing construction oversight of all critical nature-based structures such as grade controls, headwater step-pool grade controls, headwater valley regenerative stream design step-pools, bank stabilization structures and stormwater outfalls. [post_title] => Tinker's Creek Stream Restoration [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => tinkers-creek-stream-restoration [to_ping] => [pinged] => [post_modified] => 2024-07-11 15:18:40 [post_modified_gmt] => 2024-07-11 15:18:40 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=7889 [menu_order] => 94 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [5] => WP_Post Object ( [ID] => 7363 [post_author] => 1 [post_date] => 2021-04-19 18:26:06 [post_date_gmt] => 2021-04-19 18:26:06 [post_content] => Princeton Hydro designed, permitted, and provided regulatory support, including an Environmental Assessment and Environmental Baseline Survey, for this non-tidal wetland and stream mitigation project at the Mattawoman Creek Mitigation Site (MCMS) in Pomfret, Charles County, Maryland. The MCMS is the primary site included in the United States Air Force at Joint Base Andrews (JBA) Mitigation Bank, which provides advanced wetland and stream mitigation credits within the Potomac Basin that can be applied to address anticipated mitigation requirements tied to future capital improvement projects at JBA or other Department of Defense facilities. This project consists of a combination of freshwater wetland creation and restoration; hydraulic & hydrologic enhancement; re-establishment of vegetative composition and structure; and upland forest restoration buffering the wetland components of the bank. This restoration project provides over 40 wetland mitigation credits and 3,700 linear feet of stream restoration on 81 acres of land. Key project components included a stream assessment of Old Womans Run, and an unnamed tributary, to evaluate existing conditions and determine measurable stream functional uplift resulting from the planned restoration. The analysis included a watershed assessment and evaluated parameters related to the hydrology, hydraulics, geomorphology, water quality, and biology of the stream reach to be restored or relocated. A wetland water budget was developed for the proposed wetland creation and restoration to determine if sufficient water was available to establish or re-establish wetlands on the site. It was used to inform design development, including proposed grading and plant community composition. The establishment and re-establishment of wetlands was accomplished through directed grading, ditch plugging, and stream restoration designed to maximize the retention of surface water, floodplain reconnection, and groundwater inputs. [post_title] => Mattawoman Creek Mitigation for Joint Base Andrews [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => mattawoman-creek-mitigation-for-joint-base-andrews [to_ping] => [pinged] => [post_modified] => 2024-07-11 15:30:13 [post_modified_gmt] => 2024-07-11 15:30:13 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=7363 [menu_order] => 101 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) ) [post_count] => 6 [current_post] => -1 [before_loop] => 1 [in_the_loop] => [post] => WP_Post Object ( [ID] => 15951 [post_author] => 1 [post_date] => 2024-11-07 18:54:42 [post_date_gmt] => 2024-11-07 18:54:42 [post_content] => The Martin Dam was constructed on an active farm in 1961 as part of USDA’s sustainable farms pond construction initiative. Martin Dam’s robust 4,000 cubic yards of placed dam material resulted in the impoundment of only 3.5 acres of surface water. Several years ago, during the removal of a beaver dam that was obstructing the dam outlet, the riser structure was inadvertently destroyed, and a large part of the earthen dam collapsed. Due to the damage, the dam was put under an enforcement action from the Maryland Department of the Environment (MDE) Dam Safety Program. Site investigations showed an outlet culvert in total disrepair and severe erosion of the dam and downstream areas. Fearing the risk to property and life from a catastrophic dam failure, GreenTrust Alliance, in partnership with Princeton Hydro, were enlisted to design, develop, and enact an emergency dam breach. The earthen dam was approximately 20 feet in height and 490 feet in length, with an impoundment of approximately 3.48 acres. The contributing drainage area was approximately 0.25 square miles (160 acres) of low density residential land use and the primary inflowing channel, Overshot Branch, was intermittent or ephemeral. The assessment and design involved probing within the impoundment, which revealed water depths averaging 4.7 feet, with a maximum of 7.5 feet, and impounded sediment depths averaging 1.0 foot, with a maximum of 3.0 feet. Princeton Hydro prepared a 35% design plan for the earthen dam removal, and this plan was subsequently approved by MDE Dam Safety with an emergency permit, forgoing the typical months-long design and review process. The dam breach was implemented in late 2018. After the dam breach, Princeton Hydro completed a hydrologic and hydraulic assessment. Pre- and post-breach conditions were modeled to determine the potential increase in flood elevations to downstream properties. In addition, a dam failure was also modeled to assess the potential risks should the dam have failed. In comparing the pre-and post-breach scenarios, 100-year flood elevations increased between 0.01 and 0.29 feet for approximately 1 mile downstream of the pond. The floodplain valley for this stream was relatively narrow which means any increases in discharge translated to larger increases on peak flood elevations compared to the total width of the floodplain. However, the narrow floodplain also acted a barrier, ensuring that flooding was mostly contained to the area around the stream itself. No additional structures were inundated as a result of the breach. Princeton Hydro, along with GreenVest and Green Trust Alliance, developed a design that enhanced in-stream habitat of the downstream reach, and allowed for passive wetland conversion and restoration of the former impoundment. [post_title] => Martin Farm Pond Emergency Dam Breach & Dam Removal [post_excerpt] => [post_status] => publish [comment_status] => closed [ping_status] => closed [post_password] => [post_name] => martin-farm-pond-emergency-dam-breach-dam-removal [to_ping] => [pinged] => [post_modified] => 2024-11-08 19:01:34 [post_modified_gmt] => 2024-11-08 19:01:34 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?post_type=project&p=15951 [menu_order] => 0 [post_type] => project [post_mime_type] => [comment_count] => 0 [filter] => raw ) [comment_count] => 0 [current_comment] => -1 [found_posts] => 6 [max_num_pages] => 1 [max_num_comment_pages] => 0 [is_single] => [is_preview] => [is_page] => [is_archive] => 1 [is_date] => [is_year] => [is_month] => [is_day] => [is_time] => [is_author] => [is_category] => [is_tag] => [is_tax] => 1 [is_search] => [is_feed] => [is_comment_feed] => [is_trackback] => [is_home] => [is_privacy_policy] => [is_404] => [is_embed] => [is_paged] => [is_admin] => [is_attachment] => [is_singular] => [is_robots] => [is_favicon] => [is_posts_page] => [is_post_type_archive] => [query_vars_hash:WP_Query:private] => 88eaf92178f9b779bb0db9d4ec921850 [query_vars_changed:WP_Query:private] => 1 [thumbnails_cached] => [allow_query_attachment_by_filename:protected] => [stopwords:WP_Query:private] => [compat_fields:WP_Query:private] => Array ( [0] => query_vars_hash [1] => query_vars_changed ) [compat_methods:WP_Query:private] => Array ( [0] => init_query_flags [1] => parse_tax_query ) [query_cache_key:WP_Query:private] => wp_query:3aacf5c9a0a413b9bcbb49abd92e3225:0.94264700 17751558140.93634700 1775155814 )
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.
As part of New Jersey Audubon Society’s Coastal Impoundment Vulnerability and Resilience Project, Princeton Hydro was contracted to inspect and analyze coastal impoundments along the East Coast.
Coastal impoundments allow for the active management of water levels, therefore creating a unique habitat that can influence a diversity of bird populations. The ability to maximize the ecological value of these relatively small impoundment areas to the benefit of numerous species is remarkable.
Ranging from coastal areas of Massachusets to Virginia, Princeton Hydro conducted visual engineering inpsections and vulnerability assessments for fourteen impoundment clusters:
The engineering team specifically looked for evidence of erosion, overtopping and other conditions that might compromise the stability of the embankments. First, the waterward area was observed to determine the relative protection that may or may not be provided by any existing marsh area or artificial structures. Second, the area inland from the impoundments was observed to determine if the impoundment was potentially providing any storm surge or energy dissipation services for inland structures which might include homes, businesses, roadways, utilities or other structures. Supplementing the desktop GIS analysis, the in-field inspection data provided detailed information on the structural integrity and vulnerability of the embankments, which provided valuable insight for management of the impoundments.
The findings of the inspections and GIS site evaluations were presented to impoundment operators from across the Mid-Atlantic region. The presentation provided the operators with knowledge which will help them improve the operations of coastal impoundments and increase the resiliency of the structures they manage.
The City of Annapolis collaborated with Princeton Hydro to achieve compliance with its National Pollutant Discharge Elimination System (NPDES) General Permit for Discharges from Small Municipal Separate Storm Sewer Systems (MS4).
The project began with mapping the storm sewer system, focusing on the subwatershed with the highest percentage of impervious surfaces. Using GPS equipment and GIS software, the team mapped the existing storm sewer infrastructure, inspected outfalls for potential illicit discharges, and traced any detected sources of contamination. During these inspections, the team identified and verified both mapped and previously undocumented storm sewer inlets, outlets, and manholes. The team also assessed the condition of each structure, collecting data on internal connections, including type, size, direction, and material.
All collected data was integrated into a GIS-based database, providing the City with a comprehensive and actionable map of its storm sewer network.
Princeton Hydro has also prepared the Standard Operating Procedures manual for this work and helped to prepare the City’s Good Housekeeping and Pollution Prevention Plans for City-owned facilities that discharge stormwater. Future work for the City will include completing an inventory and map of the remaining subwatersheds, continuing to inspect outfalls and identify Illicit Discharges, and developing new and innovative ways for the City to treat existing stormwater.
The USACE Baltimore District hired Princeton Hydro and GreenVest to conduct a mitigation project at Piscataway Creek in Prince Georege’s County, Maryland. This project involved a mitigation site search, preliminary investigation, development of Phase I & II Wetland Mitigation Plans, a wetland delineation, development of an Evaluation of Planned Wetlands analysis, a Threatened and Endangered Species Assessment, a Cultural Resources Investigation, a hydrological and geotechnical evaluation of the site, development of a topographic and boundary survey, and a fixed price turnkey mitigation.
Our team was responsible for developing designs and specifications for the ecosystem restoration and mitigation aspects of the project, including but not limited to establishing appropriate design elevations for proposed vegetation communities, plant species selection, construction scheduling, sequencing and post-construction monitoring plans, and using USACE approved CADD and design software. The wetland mitigation is distributed across eight locations on the site. Wetland hydrology leverages the extensive drainage area tributary to the mitigation site inclusive of surface and groundwater resources. The mitigation site generated 12.5 non-tidal wetland mitigation units to offset 11.42 acres of permanent non-tidal wetland impacts. The mitigation project included the preservation of about 50 acres of high quality, non-tidal wetlands, the creation of 9 acres of non-tidal wetlands, and the restoration of 1 acre of non-tidal wetlands— for a total of about 62 acres of restored, preserved, and fully integrated non-tidal wetlands in the headwaters of Piscataway Creek.
Princeton Hydro and GV-Petro Joint Venture are restoring 41,000 linear feet of urban stream using nature-based design techniques within a highly urbanized watershed. Prince George’s County borders Washington, DC to the east, and is the second-most populous county in Maryland. Working with Prince George’s County Department of the Environment and coordinating with the Maryland-National Capital Parks and Planning Commission, this full-delivery project is designed to meet the County’s Watershed Implementation Plan (WIP) and its Municipal Separate Stormwater System (MS4) and TMDL requirements. This stream restoration project was identified as a priority due to the significant levels of channel incision and the severity of erosion and its impacts on surrounding neighborhoods. Additionally, the project’s proximity to the headwater reaches located on Joint Base Andrews (JBA), and the ability to improve water quality and wildlife habitat made this project a high priority.
The design for the stream and all the tributaries within the project area will restore the channels and floodplains to naturally stable forms. During the preliminary assessment of onsite conditions, the stream and tributaries within the restoration area were classified using geomorphic assessments and hydrologic and hydraulic analysis. Once the stream types and conditions were identified, a series of restoration approaches such as floodplain creation, bank stabilization using natural materials and plantings, re-aligning straightened stream channels to have a more natural sinuosity, regenerative stream design and natural material grade control structures were used to reduce channel flow velocities and shear stress for flows greater than bankfull, reduce bank erosion and maintain bank stability, treat and attenuate stormwater flows, stabilization of outfalls and the receiving stream channels, and stabilize vertically unstable channels. The project area contained various subsurface utilities, including sanitary sewer along the entire reach, and fiber-optics and natural gas lines across the corridor. The stream restoration project will improve hydraulics, geomorphology, physicochemical, and biological stream functions through bank stabilization. It will also increase floodplain connectivity, improve bedform diversity, restore riparian buffers, and protect public subsurface utilities. In addition to water quality benefits, this project will preserve and enhance the forested floodplain and provide ecological uplift throughout the entire stream corridor.
Princeton Hydro is currently (2020) providing construction oversight of all critical nature-based structures such as grade controls, headwater step-pool grade controls, headwater valley regenerative stream design step-pools, bank stabilization structures and stormwater outfalls.
Princeton Hydro designed, permitted, and provided regulatory support, including an Environmental Assessment and Environmental Baseline Survey, for this non-tidal wetland and stream mitigation project at the Mattawoman Creek Mitigation Site (MCMS) in Pomfret, Charles County, Maryland. The MCMS is the primary site included in the United States Air Force at Joint Base Andrews (JBA) Mitigation Bank, which provides advanced wetland and stream mitigation credits within the Potomac Basin that can be applied to address anticipated mitigation requirements tied to future capital improvement projects at JBA or other Department of Defense facilities.
This project consists of a combination of freshwater wetland creation and restoration; hydraulic & hydrologic enhancement; re-establishment of vegetative composition and structure; and upland forest restoration buffering the wetland components of the bank. This restoration project provides over 40 wetland mitigation credits and 3,700 linear feet of stream restoration on 81 acres of land. Key project components included a stream assessment of Old Womans Run, and an unnamed tributary, to evaluate existing conditions and determine measurable stream functional uplift resulting from the planned restoration.
The analysis included a watershed assessment and evaluated parameters related to the hydrology, hydraulics, geomorphology, water quality, and biology of the stream reach to be restored or relocated. A wetland water budget was developed for the proposed wetland creation and restoration to determine if sufficient water was available to establish or re-establish wetlands on the site. It was used to inform design development, including proposed grading and plant community composition. The establishment and re-establishment of wetlands was accomplished through directed grading, ditch plugging, and stream restoration designed to maximize the retention of surface water, floodplain reconnection, and groundwater inputs.
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