UPSTREAM FISH PASSAGE OPPORTUNITIES AT OHIO RIVER MAINSTEM DAMS.

Brent C. Knights, Joseph H. Wlosinski, John A. Kalas, and Sean W. Bailey.  
U.S. Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse, 
Wisconsin 54603.

Twenty mainstem navigation dams with lifts of 3.3 to 12.3 m disrupt the 
longitudinal connectivity of the Ohio River, potentially affecting fish 
populations.  An assessment of upstream fish passage based on a comparison of 
the hydraulic conditions at dams and the swimming capabilities of migratory 
fishes was conducted.  This assessment suggested that upstream fish passage 
through mainstem dams might be possible when the gates are out of the water 
(i.e., open river) during high discharge periods.  Conversely during normal-flow 
conditions, high water velocities through the submerged gate openings likely 
preclude upstream fish passage.  The frequency and duration of open river, and 
hence the potential for fish passage, varied spatially with dams and temporally 
with discharge.  The frequency and duration of open-river by dam suggested that 
upstream fish-passage opportunities are variable at downstream dams (i.e., 
Louisville District), low at middle-reach dams (i.e., Huntington District), and 
rare at upstream dams (i.e., Pittsburgh District).  Despite mainstem dams, most 
migratory fishes have persisted in the Ohio River.

Keywords:  fish passage, Ohio River, migratory fish, dams, and navigation