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Penobscot River: Un-Build It and They Will Come

Part 3 of 5 in the Atlantic Salmon Series

On a rare mild day in early April, engineer Don Dow and fisheries biologist Dave Bean from NOAA Fisheries Protected Resource Division in Orono, Maine, inspected the construction of an estimated $3.2 million nature-like bypass by SumCo Eco Contracting at the Howland Dam on the Piscataquis River. This bypass is the next step in improving access to a significant amount of riverine habitat for diadromous fish, including endangered Atlantic salmon, as well as American shad, alewife, sea lamprey, striped bass, rainbow smelt, blueback herring, and brook trout.

“Excavation and other work to prepare the site for channel construction is nearly complete,” reported Dow, “including maximizing use of on-site and local rock in building the bypass and working with appropriate agencies on materials sorting and management. SumCo, the design engineer Bjorn Lake of Kleinschmidt, and George Aponte Clarke and Laura Rose Day of the Penobscot Trust are doing a great job of managing this complex project on a fast-track schedule.”

The Penobscot, New England’s second largest river, drains nearly one third of the state of Maine, with a watershed area of 8,570 square miles. The Penobscot Watershed is one of NOAA’s Habitat Focus Areas, which is particularly important habitat for 11 migratory fish species, as well as rich in cultural history that included tribal sustenance fishing and historic recreational fishing for Atlantic salmon. The focus area designation brings additional resources and attention within NOAA to the Penobscot where we are working with partners to develop and implement a comprehensive diadromous fish restoration plan.

Restoration Is a Group Effort

The Penobscot River Restoration Trust is helping to lead federal and state government agencies, hydropower dam owners, Penobscot Indian Nation, and seven conservation groups in an ambitious plan to undo two centuries of damage to habitat for sea-run fish. In 2010, the Penobscot Trust bought three dams—Veazie, Great Works, and Howland—from PPL Corporation for $24 million. The Great Works Dam was removed in 2012 and the Veazie Dam was removed in 2013. NOAA Fisheries provided approximately $21 million for the purchase of the three dams and subsequent removal of the Great Works and Veazie dams. In addition, NOAA Fisheries provided substantial technical support in the design and removal of these dams and in the design of the Howland bypass project. The hydropower companies applied for and received federal and state approvals to increase power generation at four other dams higher up in the river to maintain or increase energy generation.


This is the second Atlantic salmon spotted in 2014 at the viewing window of the new Milford lift and trap. Photo Credit: Don Dow, PE for NOAA Fisheries.

Sea-Run Fish Get a Lift

Fish now swim freely from the sea up to Old Town, Maine, where a new state-of-the-art fish lift and trap was installed at the Milford hydroelectric facility in 2014. The new fish lift brings upstream-migrating fish over the dam, allowing them access to the river up to the Howland Dam. The lift is designed to pass 12.500 Atlantic salmon, 633,000 American shad, and 3.8 million alewife.

“The fish lift seems to be operating well, but only more field testing will tell for sure how successful it will be,” says Dow, who helped design the lift. “We have designed the lift with a high degree of variability in flow rates, water velocities, and headlosses in order to maximize our options to find the best settings at attracting and capturing upstream migrants.”

When the Howland fish passage is complete, sea-run fish will have access to historic spawning, nursery and rearing grounds they haven’t used since the 1800s.

Ice Jams and Dams

Despite cold temperatures and two-foot-deep ice on the rivers this winter, construction on the fishway carried on. As spring comes to Maine, the National Weather Service in Caribou has been monitoring the risk of floods due to melting ice and ice jams. The stretch of river upstream of the Howland Dam has been known to flood because of ice jams in the past. Before removing the Great Works and Veazie dams, the Army Corps of Engineers studied the possible effects of dam removal on ice dynamics on the Penobscot River. Their report concluded that frazil ice (long loose crystals) could form a longer single ice jam in the lower river instead of above the Veazie Dam, but otherwise would not affect the likelihood of ice-jam related flooding. At this point in the season, ice-out has occurred on the Penobscot, but rivers are still running high from snow-melt.


Let the race begin! In August 2014, the Penobscot Nation held the First Annual Bashabez Run, a 15-mile canoe race between Indian Island and Brewer in the Penobscot River. Named for Chief Bashabez, who Samuel de Champlain witnessed leading a fleet of canoes along the Penobscot River, the race takes advantage of the new dam-free stretch of river. Building on this success, from July 16-22, 2015, the tribe will host, supported by local businesses, communities, and organizations, the Penobscot River Whitewater Nationals

Monitoring the Returns

Implementation of the lower river dam removals has been accompanied by a monitoring program that evaluates ecosystem response. Ten coordinated, long-term studies of physical, chemical, and biological measures began in 2009 to document baseline conditions and most have now collected a season of post-removal data. Although restoration doesn’t happen overnight, there are early signs of recovery. In 2014, scientists counted more than 800 American shad, more than 180,000 river herring, and 255 Atlantic salmon at the Milford fish lift, the only dam between Howland and the sea. Prior to 2014, there were no known American shad above Milford and very few river herring. While there is still a long way to go, early data suggest that if we un-build it, the fish will come.