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Restoration Efforts

NOAA Habitat Restoration Projects

Between 1992 and 2015, NOAA, though its Restoration Center, the Habitat Conservation Division, and Protected Resources Division, have provided both funding and technical assistance for nearly 300  fish passage projects along the Atlantic Coast, the majority of these projects occurring in the Northeast region. More than 41 percent of these projects have been dam removals while other completed fish passage types include nature-like and technical  fishways, culvert removals and replacements, and stream channel restoration. River herring are the primary target species for most of these projects. Collectively, these projects have provided access to more than 2,228 river miles serving as  spawning and rearing habitats, and afforded access to 25,000 acres of ponds and lakes serving as important spawning and rearing habitats for alewife. NOAA funding for these project has exceeded $73 million, and has been matched or leveraged by another $46 million.

For completed passage barrier removal projects, NOAA requires Tier I implementation monitoring to document implementation outcome and basic effectiveness of target species passage following project completion. NOAA Tier II monitoring addresses more sophisticated ecological effectiveness questions and is conducted over longer post-project periods at selected NOAA-funded barrier removal sites. Tier II monitoring addressing project effectiveness for river herring is presently being conducted on the Penobscot River (ME), Patapsco River (MD), and Mill River (MA) passage restoration sites.

NOAA, in collaboration with the U.S. Geological Survey (USGS) and the U.S. Fish and Wildlife Service (USFWS) seek to improve passage by river herring and other diadromous fishes at barrier removal sites by developing passage design guidelines for Atlantic Coast diadromous fish species. The federal interagency guidelines are specifically for the design of nature-like fishways and to assess passage conditions at completed passage sites.

Penobscot River Restoration: Great Works and Veazie Dam Removals and Howland Dam Bypass

The Penobscot River Restoration Project (PRRP) is the successful outcome of many years of negotiations amongst the previous dam owner, Pennsylvania Power and Light, the current dam owner, Brookfield, the U.S. Department of the Interior, the Penobscot Indian Nation, the State of Maine, and multiple non-governmental organizations (NGOs; Atlantic Salmon Federation, American Rivers, Trout Unlimited, Natural Resource Council of Maine, among others). As part of the PRRP, Great Works Dam, the second mainstem dam on the Penobscot River, was removed in 2012 and Veazie Dam, the first mainstem dam on the Penobscot River, was removed in 2013. Late in 2015, the large nature-like bypass channel fishway was constructed around the Howland Dam.  As a result of the dam removals and the bypass fishway installation, 13 miles of river has now been reopened to a diverse diadromous fish assemblage, and provides improved access (habitat above one or more fishways) to 454 miles of the upstream river network and 39 lakes historically used by alewife as spawning and rearing habitats. With completion of the PRRP, blueback herring will have improved access to 93 percent of the specie’s historical spawning habitat, while alewife is now afforded improved access to 31 percent of its historical-use habitat in the Penobscot River watershed.

The Maine Department of Marine Resources previously published an Operational Plan for the Restoration of Diadromous Fishes to the Penobscot River (MDMR, 2009) which details targets and restoration goals in the Penobscot River watershed. The plan goal is to restore alewife and blueback herring populations to self-sustaining levels in historical habitat within 40 to 48 years. The plan outlines restoration for alewife in thirteen Phase 1 priority lakes beginning in 2010, followed by restoration of an additional 18 to 22 Phases 2 and 3 lakes, based on a timetable linked to the return success of the Phase 1 lake access projects. The plan also includes scheduled monitoring of adult river herring returns at hydroelectric dams on the Penobscot River.

Other Barrier Removals Restoring River Herring Populations

Gulf of Maine Fishways

NOAA’s Restoration Center has also partnered with state and local community organizations to complete priority passage projects on other rivers and streams in the Gulf of Maine. Recently complete projects include the Pokey Dam Fishway, East Machias River: In 2014 a Denil fishway was constructed at the outlet of Crawford Lake in Downeast Maine, providing alewife access to 4,591 acres of high-quality spawning and rearing habitats in Crawford, Lower Mud, Upper Mud, and Pocomoonshine Lakes located in the East Machias River watershed. This structural fishway replaced an old failing, wooden fishway that no longer provided effective alewife passage. Nequasset Lake Fishway, Nequasset Stream: A structural pool-and-weir fishway was constructed in 2014 at the outlet of Nequasset Lake on Nequasset Stream, a tributary to the lower Kennebec River. This project replaced a concrete-and-wood fishway that had fallen into disrepair, and restored alewife access to 392 acres of lake spawning habitat. In 2015, a rock ramp fishway constructed on Patten Stream in Surry, Maine, a tributary to the Union River, using granite boulders recycled from the historic "Singing Bridge" in Downeast Maine. This project has restored alewife passage to approximately 1,100 acres of spawning habitats in multiple upstream lakes and ponds.

Town Brook Dam Removals

Town Brook is a small but highly important 1.5-mile long stream that runs from the Billington Sea, a 269-acre lake, to Plymouth Harbor in Plymouth, Massachusetts. Historically, the river sustained important migratory fish runs of alewife, blueback herring, and rainbow smelt.  Beginning in the 1790s, six dams were constructed or reconstructed on Town Brook. In the recent past to address the dwindling fish runs, the Massachusetts Division of Marine Fisheries netted and trucked river herring around the dams and released them into their upstream spawning grounds. With assistance from the NOAA Restoration Center and many other project partners, the Town of Plymouth has restored fish passage on Town Brook. Fishways were first replaced at two of the dams at Newfield Street (2001) and the Jenney Grist Mill (2006). The Billington Street dam and its non-functioning fish ladder were removed in 2003, and the stream and riparian habitat upstream of the former barrier were restored to natural conditions. River herring telemetry studies funded by NOAA documented high passage efficiency at this restored site. The Billington Street dam project was the first dam removal in Massachusetts addressing river herring passage restoration and provided a precedent for future dam removals for diadromous fish passage in the state. The Water Street bridge reconstruction and barrier removal at the head-of-tide were completed in 2014 to allow river herring to effectively pass upstream throughout the normal tide cycles. The Off-Billington Street dam was removed in late 2014 and the restored stream reach now provides unimpeded fish passage at and upstream of this location. The Plymco Dam was removed in early 2015 and the upstream reach has also been restored for river herring passage. Engineering design is now underway for the removal of the Holmes Dam, with removal expected in 2017. To date, more than $4 million have been spent on multiple fish passage and stream restoration projects on Town Brook through 2015.

Acushnet River Nature-like and Structural Fishways


The Acushnet River has been the focus of a large-scale effort to restore river herring and American eel populations by improving access into the New Bedford Reservoir – the primary spawning and nursery habitat for alewife. A cooperative effort between the Massachusetts Division of Marine Fisheries (MA DMF), the National Marine Fisheries Service (NMFS), and the U.S. Fish and Wildlife Service (USFWS) focused on fish passage improvements at three barriers on the river. Prior to project implementation, three barriers on the 4-mile long Acushnet River impeded herring passage to more than 220 acres of upstream spawning and rearing habitats.  The most upstream barrier (New Bedford Reservoir dam, 11-feet high), was fitted with a Denil fishway in 2002. Fish passage at the lower two barriers was completed in 2007 with the installation of step-pool nature-like fishways at each the Sawmill dam and Hamlin Street dam sites. The average run size on the Acushnet River prior to these fish passage improvements was less than 400 river herring, annually.  Following construction, there has been an increasing trend in annual herring run size, with the 2013 run size 1,870% greater than pre-construction conditions. The Acushnet River herring run is expected to reach a run size in the tens to hundreds of thousands of returning adults, annually (See Technical Report). The Buzzards Bay Coalition, a lead non-governmental organization for the project, has additional information on the Sawmill site restoration. NMFS was the lead agency for the design, permitting, and construction of the two nature-like fishways, and managed these two projects on behalf of the New Bedford Harbor Trustee Council (NBHTC). MA DMF was the lead agency for the design, permitting, and construction of the technical fishway at the New Bedford Reservoir Dam. All of the fish passage improvement work, including monitoring, was funded through the NBHTC. The MA DMF has been monitoring the runs on the Acushnet River annually since 2005. To census the river herring population and other species assemblages, MA DMF installed a sampling trap at the top of the New Bedford Reservoir Denil fishway. An electronic counter was also installed at the trap exit to record numbers of fish passing during periods when manual counts and species identification are not conducted. Lastly, restoration of the Sawmill Dam property was completed in fall 2015. This important restoration project removed multiple acres of pavement and other debris, and restored the on-site habitats including red maple swamp and emergent marsh habitats providing water quality, wildlife habitat, and public passive recreation and education benefits.

Saugatucket River Fishway Reconstruction

NOAA worked collaboratively with the Rhode Island Department of Environmental Management (RIDEM) and the U.S. Fish and Wildlife Service (USFWS) as natural resource damage trustees to use funds from an oil spill settlement to supplement another NOAA natural resource damage settlement and funds through Sportfish Restoration Aid funds to reconstruct two Denil fishways on the Saugatucket River in South Kingstown, Rhode Island. The Saugatucket River, with its17-square mile watershed, flows into Pt. Judith Salt Pond and Block Island Sound, coastal waters that were affected by the 1996 North Cape oil spill.  The fishways were originally constructed on the Saugatucket River in 1970 to restore a river herring run. More recently, the fishways were determined by NOAA and USFWS as ineffective in river herring passage due to excessive fishway slopes and poorly sited entranceway. The upper Palisades Mill fishway reconstruction was completed in fall 2014; the lower Main Street fishway reconstruction along with several nature-like stone weirs and an outmigration structure to afford safe downstream migration by juveniles were completed in early 2016. Reconstruction of these fishways is expected to result in substantially increased numbers of river herring passing these dams to access 300 + acres of spawning habitat in upstream ponds and Indian Lake.  The improved fish passage is expected to increase the size of the river herring run to tens of thousands of fish, annually.

Ed Bills Pond Dam Removal


Led by the Connecticut Department of Energy and Environmental Protection (CT DEEP), along with partnering American Rivers (AR), The Nature Conservancy (TNC) and NOAA, this dam removal was targeted as a high-priority river herring restoration on a tributary to the lower Connecticut River. The project, completed in early 2016, involved the removal of the 10-ft high, run-of-the-river, stone dam located on the lower perennial East Branch of the Eight Mile River in Lyme, Connecticut. The Eight Mile River is a federally-designated Wild and Scenic River, and the project included the removal of the dam structure and accumulated sediments from the dewatered impoundment. The 1200-ft long river channel is being restored using construction practices including soil wraps for slope protection, two cobble and gravel riffles for channel grade controls, root wad deflectors, and tree and shrub native planting and seeding. The project benefits passage of river herring, American eel and sea lamprey, plus provide habitat for native brook trout and other resident fishes. In the late 1990s, a steep pass fishway was installed at this Ed Bills Pond Dam by the CT DEEP. NOAA was one of a number of project partners that contributed funds to design and installation the fishway. More recently, the partners determined low passage efficiency due to the site conditions and location of the fishway entrance. Through the NOAA-AR Partnership, funds were secured to meet a project shortfall, and with the design and permitting already completed, the dam removal moved forward with CT DEEP and TNC providing construction oversight.

Bride Brook Culvert Replacement

In 2006, the NOAA Restoration Center began working on assessment and design of a culvert to replace two undersized elliptical culverts at the tidal mouth of Bride Brook to Long Island Sound at Rocky Neck State Park in East Lyme, Connecticut. Culverts at this site were originally installed in 1934 as part of a Federal Works Progress Administration project, and replaced by the dual culverts in 1981. One of the culverts was non-functional, and the second culvert had hydraulic flows which adversely affected passage by alewife. Historically, Bride Brook was known to have a significant run of herring, typically runs of up to 175,000 adults, annually prior to the installation of the former dual culverts. As the culverts fell into disrepair, the annual river herring run size dwindled, substantially. This small but highly important stream, with a length of 2 miles and traversing through a 78-acre tidal marsh, discharges from Bride Lake, a 72-acre waterbody with high water quality and no development along its entire shoreline, providing excellent spawning and rearing habitat for alewife. In 2009, NOAA, through the American Recovery and Reinvestment Act, awarded funds to Save the Sound (STS) to remove the derelict culverts, install a new larger, concrete box culvert and low-level stone groins at the beachfront, and restore the dune system (13,000 beachgrass plugs were planted by volunteers) through which the culvert was installed. Besides STS and NOAA, project partners included the Connecticut Department of Energy and Environmental Protection (CT DEEP), Natural Resources Conservation Service, USFWS, and Fish America Foundation. CT DEEP with assistance from STS and NOAA oversaw the culvert and groin installation, successfully completed in early 2010.  The CT DEEP has been monitoring the site with an automated fish counter installed at the outlet of Bride Lake. Funds for the fish counter were provided through the NOAA-STS RAE Partnership. The river herring run size has increased substantially, reaching more than 363,000 in 2013, 265,000 in 2014, and 218,000 in 2015. This run size well exceeds the numbers historic run numbers in the 1970s before the former culvert fell into disrepair; and it is anticipated that the run may fluctuate over the years but further increase in size in future years. Now during springtime alewife spawning in Bride Lake, the shoreline boils with spawning alewife activity which attracts ospreys, bald eagles, and other wildlife in search of food.

Raritan River Passage Restoration

NOAA has been involved with passage restoration on the Raritan River in New Jersey for more than a decade. The NOAA Restoration Center began a diadromous fish database and photographic inventory of the major dams beginning in 2004. NOAA and NJDEP worked closely together to establish the Raritan River Fish Passage Initiative in 2008 bringing together stakeholders from other state, local and federal agencies, non-profit organizations, utilities and private dam owners. Three dams on the main stem of the Raritan River were removed under a State Natural Resources Damage Settlement between NJDEP and the El Paso Corporation (now Kinder Morgan) for injuries to NJ waterways resulting from contamination to ground water and surface waters at three industrial locations. These include the Calco dam, removed in 2011, the Robert Street dam, removed in 2012, and the Nevius Street dam, removed in 2013. The Calco dam, the most downstream barrier, was notched to allow passage during higher flows, sometime prior to 2003. Shad and river herring observations began in 1996 at a fish way viewing window installed by NJDEP at the Island Farm Weir at River Mile 22. The annual run size prior to dam removal was typically less than 1,000 of combined American shad and river herring. In the year following the removal of the Calco dam the survey count was 495 individuals. In 2014 shad passage was documented one mile upstream of the former Robert Street dam, giving indication that shad and river herring are now migrating to the base of the next full impediment known as the Head Gates Dam. This dam has been targeted for future removal by USFWS, NOAA and NJDEP. Rutgers University is under contract with the NJDEP to continue the Island Farm Weir viewing window surveys through 2016. Researchers have replaced VHS viewing with digital infrared cameras that collect data during both day and night conditions. Additionally Rutgers has added a radio tagging and tracking program which allows researchers to monitor passage efficiency through the fishway. The Raritan River Fish Passage Initiative partners continue to work to a goal of restoring fish passage in the Raritan River with the removal of the Weston Mill Dam on the Millstone River in 2017 and the design and construction of an technical fishway at the Island Farm Weir by 2020.

Patapsco River Dam Removals

In 2010, NOAA, the Maryland Department of Natural Resources and American Rivers completed the demolition of the Simkins and Union Dams on the Patapsco River near Ellicott City, Maryland. These projects are critical components of what will be the largest river restoration in the state of Maryland, and will establish a model for future dam removal efforts in the Chesapeake Bay watershed. The primary objective of these removals is to restore healthy spawning and rearing habitats by opening 65 miles of habitat for target fish species including river herring, American shad and American eel. A third dam and the first blockage on the Patapsco River, Bloede Dam, is scheduled for removal in 2017.  Once removed, diadromous fishes will have free access to upriver reaches for the first time in more than 100 years.  Large-scale monitoring efforts are underway by the Maryland Biological Stream Survey to record returns of diadromous species including abundance measures of river herring in the watershed. Other monitoring includes river cross-sections for repeat topographic surveys and bed sediment grain-size sampling; areas where high-density points are repeat-surveyed to develop and update digital elevation models (DEMs) of erosional and depositional hotspots; and installation of three U.S. Geological Survey gauges where river and suspended sediment discharge data are being collected for further analysis on the restoration of the river.

Planning for Passage Restoration: Chesapeake Bay Fish Passage Prioritization

The Chesapeake Bay watershed covers over 64,000 square miles, has over 140,000 miles of mapped rivers and streams, and includes more than 5,000 dams, most of which are barriers to diadromous fish species. The NOAA Restoration Center, working in concert with members of the Chesapeake Bay Fish Passage Work Group (CBFPWG) and the U.S. Fish and Wildlife Service (USFWS), has developed a geographic information system to support resource agencies in identifying and selecting dams for removal in the Bay watershed. This web-based tool identifies high-priority dams aimed at reconnecting fragmented river and stream habitats by removing or bypassing key barriers to fish passage, with the goal to restore or enhance populations of target species such as alewife and blueback herring. Since 1989, the CBFPWG has reopened more than 2,730 miles of stream habitat for diadromous fishes.  

NOAA and USFWS have used this tool to rank and target dam removal projects in the Chesapeake Bay watershed that produce the greatest ecological gains for target species in the Chesapeake Bay, and have partnered together on dam removal projects such as Bloede Dam on the Patapsco River (MD), Centreville Dam on Gravel Run (MD), and Harvell Dam on the Appomattox River (VA). The tool is available to the public.