This holiday season, the fish that call the Patapsco River home will receive a gift for which they can truly be thankful - the removal of a dam that has restricted their movements for more than a century.

Officials with the National Oceanic and Atmospheric Administration have breached the Simkins Dam, a structure across the Patapsco in the Ellicott City, MD, area that is 10 feet high and 200 feet long. The dam was built to provide power to the Simkins Mill, which recycled cardboard, but hasn't been used in decades, according to NOAA engineer Mary Andrews.

"It really has no useful life at this point for the industry. What it has really become for the industry is a liability," Andrews said.

The Simkins Dam removal project is part of an initiative between NOAA and American Rivers to restore the Patapsco River by removing all of its dams, which have restricted the mobility of river herring, eel and shad for decades.

The dams also affected some freshwater mussel larvae, which must attach themselves to eels during part of that life cycle; if the eels can't pass, the mussels are stuck, too.

Officials with the project estimate that the work on Simkins Dam will be completed by January. Already, the backhoes have taken away Union Dam. In 2012, they hope to remove Bloede Dam, and after that, the Daniels Dam.

When all four are removed, Andrews said, the fish will have 175 miles of the river available for swimming and spawning. And, the concrete from the dams will be used as substrate for oyster reefs.

Dam removal varies in cost - Simkins will run just shy of $1 million. NOAA received funds for the projects through the American Recovery and Reinvestment Act.

Since the Bay Program began in the 1980s, the success with fish passages has been one of the few bright spots in restoration progress.

From 1988 through 2005, the Bay Program restored 1,838 miles of fish passage, surpassing the original goal. The program's managers increased the fish passage restoration goal to 2,807 miles by 2014. During the first three years, they have gotten 81 percent of the way there.

Fish elevators have been placed in many of the blockage spots. But those do not help all species, and evidence shows that a species can get past one blockage but get caught in the next one, according to Serena McClain, director of river restoration at American Rivers.

Also, leaving dams can be dangerous for swimmers; several people have drowned at Bloede, which is in a popular swimming area at Patapsco Valley State Park. In many cases, the companies that own the dams no longer maintain them.

McClain and Andrews were excited to work together on the Patapsco because the project involves not only removing these barriers, but restoring a whole river system.

"We still have a way to go here. There are still thousands of blockages throughout the Bay," McClain said. "We really want to make sure it continues to be a priority for the Bay Program and the Bay states. These are very much multipurpose projects."