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Bay Blog: fish passage

Aug
28
2013

Patapsco River dam removal will restore miles of fish passage

More than 40 miles of the Patapsco River will be opened to the annual migrations of herring, alewife and American shad once the waterway’s lowermost dam is removed.

Bloede Dam has blocked the passage of migratory fish for close to a century. It has also posed a public safety hazard, creating strong currents that have killed a number of swimmers. Its removal is the next step in the Patapsco River Restoration Project, and will be funded by a $3.57 million grant from the National Oceanic and Atmospheric Administration (NOAA)’s Restoration Center to American Rivers.

American Rivers has worked on the Patapsco project for the past five years with NOAA, the Maryland Department of Natural Resources (DNR) and the Friends of the Patapsco Valley State Park. The river’s Union and Simkins dams were removed in 2010 and 2011 in order to create better habitat for fish and a safer swimming hole for people.

“Removing one dam can make a major difference in the health of a river and its fisheries. But removing multiple dams… is really a game-changer,” said Serena McClain, director of river restoration at American Rivers, in a media release.

The Chesapeake Bay Program tracks the opening of fish passage as an indicator of Chesapeake Bay health, and has achieved 91 percent of its goal to open more than 2,800 miles of fish passage by 2014. Because dams, culverts and other barriers can disrupt the natural flow of rivers, their removal can mean a boost in habitat, a drop in pollution and improved protection from flooding.

Learn more about the removal of Bloede Dam.



Aug
06
2012

American eel numbers rise after dam removal

American eel numbers are up in the headwater streams of Shenandoah National Park, following the 2004 removal of a large downstream dam.

Significant increases in upstream American eel populations began two years after the Rappahannock River's Embrey Dam was removed and have continued nearly every year since, according to a report released last week by the U.S. Geological Survey (USGS), U.S. Fish and Wildlife Service (USFWS) and National Park Service (NPS) researchers. 

Image courtesy EricksonSmith/Flickr.

Dams can act as travel barriers to American eels, which undertake long-distance migrations from their ocean spawning grounds to freshwater streams along the Atlantic coast. While American eels can surpass substantial natural barriers--like the rapids of the Potomac River's Great Falls, for instance--dams pose a more difficult obstacle and have contributed to the widespread decline in American eel populations. Dam removal, therefore, could have long-term benefits for eel conservation.

"Our study shows that the benefits of dam removal can extend far upstream," said USGS biologist Nathanial Hitt. "American eels have been in decline for decades and so we're delighted to see them begin to return in abundance to their native streams."

Embrey Dam, which once provided hydroelectric power to Fredericksburg, Va., was breached in 2004 following years of work by nonprofit organizations and city, state and federal government agencies. Its removal was intended to benefit more than the American eel, however, as dams can impact a number of fish that must migrate up rivers to spawn.

"Shad, herring and striped bass are also using reopened habitat on the Rappahannock River," said Alan Weaver, fish passage coordinator for the Virginia Department of Game and Inland Fisheries. "It's exciting to see a growing number of species benefiting from dam removal in Virginia."

Learn more about American eel abundance in Shenandoah National Park.



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