Eighteen years after restoring flow to an important section of the Roanoke River, populations of key species are growing.
Hydroelectric dams play an important role in generating energy. However, they also alter a river’s natural flow and limit access to upstream habitat essential to migratory fish species. Eighteen years ago, NOAA Fisheries and partners restored flow to a section of the Roanoke River that had been bypassed for five decades. Long-term monitoring of this area is showing a steady increase in the number of resident fish, notably the American eel. Freshwater mussels, including highly vulnerable species, have also begun to flourish. Interestingly, American eel may play a role in the sudden increase in these mussel populations.
The Roanoke Rapids Dam was built in 1955. Since that time, dam operators have diverted the majority of downstream flows through a channel that carries water away from the powerhouse. This cut off the flow to a 331-acre portion of the river adjacent to the channel, which became known as the bypassed reach. In 2004, the Federal Energy Regulatory Commission issued a new license to Dominion Energy to operate the hydroelectric dam. At that time, NOAA Fisheries and partners requested that flow be restored to the bypassed reach to improve fish passage at the dam.
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