Science writer Cheryl Lyn Dybas features the Raritan River and the dam removal work of Hydrogeologist John Jengo in her article “Birds Follow Flyways, Fish Navigate Swimways” published this week in the journal BioScience. Ms. Dybas also highlights research by Rutgers biologists Olaf Jensen and Anthony Vastano, who track the impact of dam removal on local fish populations in the Raritan, and cites additional research by Rutgers ecologist Julie Lockwood who is using eDNA (environmental DNA) to monitor the comeback of river herring and American shad in the Raritan. Cool stuff!
Ms. Dybas’ piece provides a fascinating global perspective on habitat connectivity, and contextualizes our local-to-the Raritan dam removal and fish passage efforts in a larger movement to save migratory fish species (World Fish Migration Day is May 21, 2022). We are so grateful for her attention and reporting on this work!
The dam on the Lamington River at Burnt Mills was scheduled for removal after several iterations of mills beginning in early colonial times circa 1754.
Dams and mills came and went on New Jersey rivers and streams. Some destroyed by floods, fire or angry upstream neighbors deprived of migrating fish. British troops did their part and burned the mill on the Lamington, in Bromley, which was henceforth named Burnt Mill. These days the dams are being removed by private organizations and groups in cooperation with the National Fish and Wildlife Service. These organizations are dedicated to the restoration of rivers and the downstream benefits to native wildlife and soil stability.
Hundreds of dams across the country have been removed or are being scheduled for removal. The results are, for the most part, shockingly positive. From California to Maine, stories of returning fisheries, reduction in sediment accumulation, reduced flooding and a greater diversity of wildlife have been documented.
Every dam is its own story, its significance dependent on location. Downstream of the Lamington, on the lower Raritan, removal of dams allowed the upstream travel of anadromous fish.
In colonial times, netting alewives and shad as far upstream as Raritan, generated a profitable commercial fishery. Mills and dams put an end to that business.
Most early mills were situated on feeder streams to avoid seasonal floods and raging current. The Lamington dam was perfectly situated in that regard.
Mature trees lined the banks to stabilize the soil and as a result the stream bed suffered minimal erosion during seasonal flooding. Runoff was minimal due to the surrounding land being unsuitable for farming. Even today as development has exploded, the stream bed of the upper Lamington and Rockaway is mostly sand and gravel. The difference is striking when compared to the nearby lower South Branch which suffers from erosion and a build up of silt.
The low concrete dam across the Lamington had been breeched in the early 1950s and misdirected the streamflow into the opposite shore causing severe erosion. An aerial view comparing the intact structure in 1953, to breeched version in 1956, shows the progress of the resulting erosion. An aerial view as seen today, compared to 1956, is even more dramatic.
The Lamington is the recipient of water released from Cushetunk Lake and Round Valley reservoir via South Rockaway creek as well as runoff from extensive upstream development. The added flow into the lower Lamington has hastened its meandering as directed by impervious shale cliffs and the concrete dam. Concrete walls designed to prevent erosion, speed the streamflow otherwise slowed by natural shorelines. Concrete walls line an upstream golf course, and another wall lines an outside curve along the road about a half-mile above the dam. During times of planned water release and seasonal storms, the water volume and speed create a high-pressure nozzle at the point of the breeched dam. The sum of upstream water, that makes up the Lamington, flows around a sharp bend a few hundred yards above the dam, careens off the high straight wall of red shale, slams into a concrete barrier perpendicular to its flow, then left, into a bank of unstable soil.
Free flowing rivers exhibit pure energy and it is energy and movement that define life. Science aside, it is the magic of perpetual motion and endless flow that we embrace. Flowing water is a magic carpet which requires no effort to travel, whether it be by vessel or imagination.
Any interruption of the energized free flow is representative of progressive pathology and an existential threat. The ‘damnation’ of rivers and streams represent stasis, blockages and clots; their removal, a life saving intervention.
So it was, the landmark Burnt Mill dam came down. Mixed feelings for those whose youthful memories were cast into the concrete substructure. The sight of the dam served as a reminder of an idyllic time and sunny days. A momentary retreat from the harsh reality that, on occasion, bites us all, was erased.
The removal was well planned and orchestrated as opposed to a charge of dynamite and a call of, ‘fire in the hole.’
The course of the river needed to be shifted and so large boulders were placed strategically to form the foundation of a left bank to replace that which was lost.
A 323 Caterpillar excavator fitted with tracks, moved into the river above the dam and began to scoop river bed gravel to line the upstream side of the length of the concrete dam. Apparently, this prevented water from flooding the work area during removal. Boulders in place, a second 323 Cat positioned on the downstream side, fitted with a ram driven spike, began to break up the concrete starting at the midstream end, working toward the right shore. It appeared the first foot and a half was easily penetrated. The second and third pass strained the hydraulic ram, the concrete’s resistance futile. After each session with the spike, the front-end loader scooped up the rubble and dumped it in-line with the boulders to form a new shoreline. The effort continued and half the dam was broken up and redistributed in about four hours. https://vimeo.com/367086739
Work continues as the removal of the dam was the first step in restoring the Lamington to its original course, pre-1754.
A new generation will know a different river, just as the last generation knew only a river interrupted by a dam.
Author Joe Mish has been running wild in New Jersey since childhood when he found ways to escape his mother’s watchful eyes. He continues to trek the swamps, rivers and thickets seeking to share, with the residents and visitors, all of the state’s natural beauty hidden within full view. To read more of his writing and view more of his gorgeous photographs visit Winter Bear Rising, his wordpress blog. Joe’s series “Nature on the Raritan, Hidden in Plain View” runs monthly as part of the LRWP “Voices of the Watershed” series. Writing and photos used with permission from the author. Contact email@example.com. See more articles and photos at winterbearrising.wordpress.com.
The LRWP has submitted the following letter in response to NOAA’s Invitation to Public Comment on their “Restoration Plan/ Environmental Assessment Draft (RP/EA) for the American Cyanamid Co. Superfund Site, Bridgewater Township, Somerset County, New Jersey”:
May 23, 2016
NOAA Restoration Center – Sandy Hook Office
JJ Howard National Marine Fisheries Science Center
74 Magruder Rd, Highlands, NJ 07732
RE: American Cyanamid Draft RP/EA
Dear Mr. Alderson –
The Lower Raritan Watershed Partnership has reviewed NOAA’s proposed Restoration Plan/ Environmental Assessment (RP/EA) for the American Cyanamid Co. Superfund Site, Bridgewater Township, Somerset County, New Jersey and fully supports the proposal for primary and compensatory restoration activities.
The LRWP is New Jersey’s newest watershed association, 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. We believe that not only will removal of the Weston Mill Dam on the Millstone River directly improve resources impacted by legacy contamination, it is our understanding that the proposed project will benefit a broad spectrum of the Raritan River’s ecology and will likewise 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. Likewise, we expect that design of technical fish passage at the Island Farm Weir (located on the Raritan River) will advance multiple Lower Raritan Watershed stakeholder goals.
The LRWP is also aware that the removal of the Weston Mill Dam on the Millstone River, as well as future modifications at the Island Farm Weir to include a technical fish passage at the Island Farm Weir on the Raritan River, will expand access to several thousand acres of non-tidal freshwater mid to upper reaches of the Raritan River’s major tributaries. Removal of Weston Mill Dam and the construction of a technical fish passage at Island Farm Weir will significantly 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 NOAA’s proposal are short term sediment transport impacts following dam removal. However, we are confident that NOAA’s plan to reduce potential environmental consequences is sound 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 the Weston Mill Dam on the Millstone River and feasibility analysis and design of technical fish passage at the Island Farm Weir are important to the LRWP and we fully support the proposed projects.
The National Oceanic and Atmospheric Administration, the Department of Interior, and the State of New Jersey invite public comment on a proposed plan.
The Draft RP/EA is available at the following website:
The public comment period on this plan ends June 10, 2016.
To request further information or an additional hard copy of this document or to submit your comments, please contact Carl Alderson at (732)371-0848, NOAA Restoration Center – Sandy Hook Office, JJ Howard National Marine Fisheries Science Center, 74 Magruder Rd, Highlands, NJ 07732 or by email at Carl.Alderson@noaa.gov. Please put “American Cyanamid Draft RP/EA” in the subject line.