Rock Arch Rapids, Lock and Dam #1, Cape Fear River, NC

Three locks and dams are located on the Cape Fear River in Bladen County, NC.  These locks and dams were construction between 1915 and 1935 to provide for commercial navigation between Wilmington and Fayetteville, NC.  Lock and Dam No. 1 is the most downstream structure.  Since construction of the locks and dams, passage of fish upstream, especially anadromous fish, has been restricted.  Anadromous fish in the river include striped bass, American shad, river herring, and Atlantic and shortnose sturgeons.  Attempts to improve passage of these fish by locking began in 1961.  Several changes in locking procedures have been made over the years with the latest changes being made in 1998.  Since these changes, several monitoring efforts using sonic tags indicate that about 50 to 65% percent of the American shad and 50 to 77% of the striped bass pass upstream of Lock and Dam #1.  However, only about 35 percent of the shad and 25 percent of the striped bass were able to pass upstream of all three locks and dam.  The success of passing other anadromous species is unknown.  As a mitigation component of deepening Wilmington Harbor, increasing fish passage efficiency was required at Lock and Dam #1.  Several alternatives were considered including improving locking procedures, removing or lowering the dam, nature-like bypass, diversion channel, and rock arch rapids.  The rock arch rapids fish passage along the entire downstream face of the dam was selected because it is predicted to maximize fish passage while protective existing water supply intakes upstream.  The rapids will also not preclude the use of the lock for vessel traffic.  Rapids construction began in June 2011 and should be complete by early spring 2013. A detailed monitoring plan has been developed to determine fish passage success for shad, striped bass and sturgeon.