Gunnison Tunnel

Project description

Completed in 1909, the 5.8 mile Gunnison Tunnel through Vernal Mesa Mountain diverts water from the Gunnison River into the Uncompahgre River in west-central Colorado. More than 100 years later, a hydroelectric facility was constructed on the outflow of the tunnel, prompting a retrofit of the tunnel intake to prevent fish passage.

A vertical electric fish barrier array was installed at the intake of the Gunnison Tunnel in 2012 to inhibit downstream passage of Rainbow Trout and prevent subsequent entrainment at the hydroelectric facility.

The vertical electrodes are suspended in the reservoir near the tunnel entrance to deter fish with a variety of approach angles. Each set of electrodes is set at differing voltage potentials and are oriented such that the tunnel inflow passes through the contiguous voltage gradient, thereby deterring fish from entering the water intake.

This suspended vertical type of barrier can cross long spans of water at varying depths with low power consumption and is useful for deterrence of downstream fish movement.