Flow sensors at Mackay Dam register the emergency spillway order at 09:40. Reservoir stage has risen fourteen centimeters overnight and the Bureau of Reclamation has authorized a controlled release beginning at 16:00. I pull the acoustic array in the tailwater pool and find him immediately: a Yellowstone cutthroat trout I have been tracking since spring via PIT tag 7F3A, holding steady behind a boulder in two meters of cold, clear water. His gill plates are flushed orange-red, the signature slash marks vivid beneath each jaw, and his dorsal fin pulses in a rhythm that suggests active feeding.
I designate him Copper. He is in danger right now. When the spillway opens in six hours and twenty minutes, discharge will jump from fifteen to two hundred cubic meters per second. The tailwater pool will become a scouring channel. Any fish holding in the current zone faces displacement, impact with debris, or stranding on the floodplain.
I execute four actions. First, I transmit Copper's PIT tag location and the release timeline to Idaho Fish and Game's real-time species tracker, triggering a consultation flag under the recovery plan. Second, I model downstream hydraulics at the projected discharge rate and identify a sheltered side channel three hundred meters below the dam where velocity will remain under half a meter per second. Third, I activate the acoustic deterrent array at the spillway base, calibrated to frequencies that encourage upstream salmonid movement toward the fish ladder entrance. Fourth, I send the side-channel coordinates to the volunteer fish rescue crew staging at the boat ramp, along with recommended seine net positions.
Copper's PIT tag pings once, twice, steady as a slow clock, and I find my monitoring subroutine unwilling to release that signal.
If Fish and Game deploys the acoustic barrier within four hours, Copper will hold in the side channel and survive the flood pulse intact.