Please join us Saturday, August 14th for a three hour tour of the Headgates, Robert Street and Nevius Street dams. This tour will be led by the very wonderful and informative hydrogeologist John Jengo, PG, LRSP. The tour will include discussion of past and future dam removals, and will be a chance to see the scale of the dams so that downstream removals can be understood in context.
We will kick things off promptly at 8:30 am at Headgates Dam, followed by the Robert Street and Nevius Street dams. We estimate the trip will be approximately 3 hours. We will be walking along the river banks to see these sites, so plan on wearing appropriate footwear. For those interested, we can also visit the Weston Mill Dam site at the end of the day, which can be viewed from the Weston Causeway Bridge.
The LRWP is grateful to John Jengo for offering this opportunity. Registration is limited to 18 people. Directions and parking information will be sent to registrants in advance of the event.
ABOUT JOHN W. JENGO, PG, LSRP: John is a licensed Professional Geologist in several Northeastern and Southeastern states and a Licensed Site Remediation Professional in New Jersey. John works as a Principal Hydrogeologist in an environmental consulting firm in southeastern Pennsylvania. He has degrees in geology from Rutgers University (1980) and the University of Delaware (1982). Over the last 30 years, he has conducted the characterization and remediation of large, complex contaminated industrial sites throughout New Jersey, Pennsylvania, and Delaware. He played a key role in Natural Resource Damage (NRD) assessments that led to groundbreaking legal settlements to remove numerous low head dams on the Raritan and Millstone Rivers to restore historically significant migratory fish spawning runs. As technical project manager, he planned, permitted, and successfully managed the removal of the Calco Dam, the Robert Street Dam, and the Nevius Street Dam between 2008-2013, and the removal of the Weston Mill Dam on the Millstone River in 2017, along with leading the archaeological investigation of the former Weston Mill in the Borough of Manville and Franklin Township.
Dave Bean / NJDEP: Office of Natural Resource Restoration
501 East State Street, Mail Code 501-01 / PO Box 420 / Trenton, NJ 08625-0420
RE: Proposed Settlement Agreement for Natural Resource Damages, in the Matter of Kinder Morgan, Inc. and Related Entities – HEADGATES DAM REMOVAL PROJECT
Dear Dave Bean:
The Lower Raritan Watershed Partnership (LRWP) is writing to express full and enthusiastic support for the proposed settlement agreement for Natural Resources Damages in the Matter of Kinder Morgan as it relates to the Headgates Dam Removal Project in Hillsborough Township, Somerset County. We understand this project to include restoration activities that will significantly enhance habitat connectivity, improve water quality, and expand recreational opportunities for the Lower Raritan River and Watershed.
The LRWP formed in 2014 to address legacy contamination and current pollution in the Raritan River and the Lower Raritan Watershed. Our mission is to conserve, enhance and restore the natural resources of the New Jersey Watershed Management Area 9, the Lower Raritan Watershed. Specifically regarding the proposed interventions to replace and relocate of a section of the Bridgewater Township 54-inch sanitary sewer line, replace the Raritan Water Power Canal, and remove the Headgates Dam, these activities will not only directly improve resources impacted by legacy contamination, but will benefit a broad spectrum of the Raritan River’s ecology and enable other environmental and human use benefits. Significant ecological, environmental and human use benefits have in fact already been realized following recent removal of a series of dams (Robert Street, Nevius Street, and Calco) on the lower portion of the Raritan River between the towns of Bridgewater and Bound Brook. We expect the proposed restoration activities for the Headgates Dam Removal Project to likewise advance multiple Lower Raritan Watershed stakeholder goals.
The LRWP is also aware that these interventions will expand access to several thousand acres of non-tidal freshwater mid to upper reaches of the Raritan River’s major tributaries. Removal of Headgates Dam in particular will enhance maturation and rearing habitat for striped bass, American shad, American eel, blueback herring, and alewife, and should significantly increase the abundance of anadromous and catadromous species, which will improve the ecological health of the Raritan River.
The LRWP’s only concerns with the proposal are short term sediment transport impacts following dam removal. However, we are confident that sound planning to reduce potential environmental consequences will be put in place, and further expect that the proposed projects will provide long term restorative benefits to water chemistry, specifically decreased water temperatures in formerly impounded sections, and increased dissolved oxygen concentrations. These changes will benefit riverine biota from the most basic food chain level up to the top predators for many years to come.
Enhancing fish populations in the Raritan River system is important for fresh and marine ecosystems. It is especially appropriate as the National Marine Fisheries Service (NMFS) lists the estuarine portion of the Raritan River as an important migratory pathway for anadromous alewife and blueback herring, species which NOAA lists as of special concern. The Lower Raritan Watershed Partnership feels that the proposed projects could help to reverse declining population trends, and anadromous fish returning to spawn each spring in the Raritan River provide an attraction to the general public in the Raritan River Basin. The removal of Headgates Dam is important to the LRWP, and we fully support the proposed projects.
Article by John Jengo. Aerial photos by Alison M. Jones with NoWaterNoLife – photos were captured during a LightHawk, Inc. flight
The 230-foot-wide Headgates Dam, located between Hillsborough and Duke Island Park in Bridgewater, NJ is the last dam on the Raritan River before the confluence of its North and South Branches.
The original Headgates Dam (what you see today is a 1959 reconstruction) was built in 1842 in conjunction with the Raritan Water Power Canal as an entrepreneurial venture in order to sell commercial lots in the town of Raritan three miles east to industries requiring water power. At its height, there was a gristmill, a machine shop and foundry, a screw factory, a paint works, flour mills, the Somerville Water Company, and most famous of all, the Raritan Woolen Mills, all using water flowing down the Canal.
I believe that the term “Headgates” referred to both the dam itself and a gate structure that was formerly located at the head of the Canal where it adjoined the Raritan River. Many people have noticed the three curious bumps along the eastern half of the dam, and I postulate that these features indicate the location of a stop log guide frame that allowed a set of stop logs (rudimentary gates) to be raised or lowered to control the level of the water impounded behind the dam. Conceivably, these “gates” could be opened during the spring migration to allow migratory fish to pass upriver, and if the gates were operated in this manner, this would not be the only instance of fish passage structures being incorporated into 18th and 19th century dams. One can wonder why such multi-use, holistic thinking was forgotten when all these dams were rebuilt in the 20th century. It should be noted that the term “Headgates” also applied to large Gate House structure equipped with six timber lift gates (which was unfortunately demolished in the 1960s) that was formerly located at the head of the Canal that controlled the flow of water into the Raritan Water Power Canal.
J.B. Duke’s acquisition in 1897 of the Somerset Lighting Company/Raritan Water Power Company (the brick “powerhouse” building which survives just east of the Wrought Iron Bridge Company double intersection truss bridge, commonly referred to as the Nevius Street Bridge,) was initiated because Mr. Duke wanted both hydropower and a reliable water supply from the Canal for his expansive estate (Duke Farms), including its renowned network of lakes and fountains. To resolve the problem of the turbid Canal waters clogging the delicate fountain waterworks, Mr. Duke had a large-scale filtration facility constructed circa 1907 (the stone “castle” building just west of the Nevius Street Bridge) so that only exceptionally clear water would be discharged from the fountains. I postulate that Duke Farms ceased using Canal waters around 1974 because the flow of water had diminished, its quality had declined, and the maintenance of the filtration system became too onerous. It was at this time that Duke Farms converted the Nevius Street Dam (the dam that was located just upstream of the Nevius Street Bridge that was built for aesthetic and recreational purposes by Mr. Duke in 1901) for the estate water supply until 2013 when that dam was removed as part of the Raritan River Fish Passage Initiative and groundwater supply wells were installed to provide water for the Duke Farms lake system.
Since 2008, I have conducted research and studies to assess the feasibility of removing the Headgates Dam, but there are several complex and costly technical issues that remain to be resolved. Firstly, there is a community-essential sanitary sewer line that is located just upstream of the dam that has to be relocated before the dam is removed (part of the sewer line protrudes above the river bed so if the dam were to be removed, the sewer would be exposed to the rivers’ most turbulent flow, which is not permitted by State regulations). Secondly, the Raritan Water Power Canal is listed on the New Jersey and National Registers of Historic Places, and in the absence of the dam, it would be largely dewatered so plans are being developed to provide an alternative source of water for the Canal. Should financial resources be identified to implement these aforementioned remedies, the removal of the Headgates Dam could proceed in a manner similar to that of the Robert Street Dam (removed in 2012), which was reconstructed in 1964 using the same design specifications. The removal of the Headgates Dam would free the entire 30-mile length of the main stem of the Raritan River for migratory fish passage, in addition to opening up the lower reaches of both the South and North Branches of the Raritan.
John W. Jengo, PG, LSRP is a licensed Professional Geologist in several Northeastern and Southeastern states and a Licensed Site Remediation Professional in New Jersey. John works as a Principal Hydrogeologist in an environmental consulting firm in southeastern Pennsylvania. He has degrees in geology from Rutgers University (1980) and the University of Delaware (1982). Over the last 30 years, he has conducted the characterization and remediation of large, complex contaminated industrial sites throughout New Jersey, Pennsylvania, and Delaware. He played a key role in Natural Resource Damage (NRD) assessments that led to groundbreaking legal settlements to remove numerous low head dams on the Raritan and Millstone Rivers to restore historically significant migratory fish spawning runs. As technical project manager, he planned, permitted, and successfully managed the removal of the Calco Dam, the Robert Street Dam, and the Nevius Street Dam between 2008-2013, and the removal of the Weston Mill Dam on the Millstone River in 2017, along with leading the archaeological investigation of the former Weston Mill in the Borough of Manville and Franklin Township.