Smith-Root Upstream Fish Barrier systems are designed to totally block the passage of all upstream migrating fish. The barriers use electric pulses designed to partially paralyze fish without causing physical injury. The pulsators are adjusted to produce an ascending electric field sufficient to gradually reduce the ability of fish to swim against the water flow. It is best to have upstream barriers located in areas of medium to high water velocity in order to sweep stunned fish clear of the electric field. Often an attraction flow is provided just below a barrier to lure fish into hatcheries, traps, fish ladders, etc.

Upstream Barrier Hydraulics

For optimum design, it is important to maintain a uniform velocity and water depth across the entire water column. To do this, the bottom must be level and the sides should be contained. The bottom should also be smooth so that a velocity is maintained near the bottom. With high velocity and homogeneous flow throughout the barrier, inhibited fish are quickly swept clear of the electrified zone. For upstream migrating adult salmon and steelhead, our upstream electrical fish barriers have proven to work well in velocities ranging from 2 to 10 ft/sec.

Static Flow Barriers

Smith-Root static flow barrier systems are designed to startle and repel the advancement of migrating fish. The pulsator intensities are adjusted to provide a constant field strength across the array. The outputs are set to produce very narrow pulses with a slow repeating pulse rate. The narrow pulses do not tetanize or reduce fishes' ability to swim. The electrode array arrangement is similar to upstream barriers except parasitic electrodes are placed at each end to produce an abrupt field edge. The abrupt field edge causes fish to be startled toward open water. Tests have shown repelling efficiencies of nearly 100% in static flows when an open body of water is available for fish to return to.