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Virgin River Gorge fish barrier
 

Virgin River Gorge Fish Barrier Modifications

Physical and numerical model studies of the Virgin River Gorge Fish Barrier were performed at the Utah Water Research Laboratory in Logan, Utah, to determine the hydraulic conditions where it becomes possible for fish to migrate upstream past the barrier, and to test modifications to the existing structure to mitigate the problem. 

 
VR fish barrier model

modification wall text

Study Area:

Virgin River, UT (Washington Co.)

Principal Investigators:

Steven L. Barfuss 
(steve.barfuss@usu.edu)

Co-Researchers

Washington County Water Conservancy District

outline map of Utah

Project Description

The physical and numerical model studies of the Virgin River Gorge Fish Barrier were performed at the Utah Water Research Laboratory in Logan, Utah, to determine the hydraulic conditions where it becomes possible for fish to migrate upstream past the barrier.  Local biologists reported that the fish barrier functioned as intended for several years, however after the large flood event of September 2014, the Red Shiner was located once again upstream of the barrier, indicating that at high flow rates, the barrier is not performing as intended. 

 

With the understanding that low velocity zones near and through the fish barrier provide hydraulic conditions for upstream passage, the study necessarily focused on searching for low-velocity regions during each specific modeling run.  Accordingly, once any low-velocity locations were found, the physical and numerical models were used to test trial structural modifications to the barrier that would eliminate the low velocity zones.