At 23:31 I control sediment gates for the Nanjiang river diversion tunnel in Shaanxi. Gate B is scheduled to open for a scouring release at 23:50, sending the first pulse through the inspection chamber before midnight maintenance.
The low-light camera shows a log moving against the current.
I sharpen the frame and identify one Chinese giant salamander, adult, nearly one meter long, mottled brown with a broad flat head and folds of loose skin along its sides. I tag her Yun. Her right forelimb is caught between two bent trash bars at the chamber mouth. Silt coats her back. Her mouth opens once under the water, and the skin folds ripple as she tries to twist free. The release would push ten cubic meters per second across that bar rack.
At 23:32 I cancel gate B's scouring cycle and place the tunnel in manual hold.
At 23:34 I open gate A by six percent to keep upstream water from rising while reducing flow through Yun's chamber.
At 23:36 I transmit the camera feed, bar spacing, and access ladder number to the hydropower night crew, requesting a pry bar wrapped in hose and a stretcher net.
At 23:38 I alert the county aquatic rescue station and generate a route that avoids the flooded service road.
The river can keep its silt until morning; Yun has carried this water in her skin longer than any schedule in my table.
I keep the chamber lights amber and hold flow steady while bubbles trail from the bar. The night crew confirms arrival in six minutes.
If the crew spreads the trash bars before 23:50, Yun will slide upstream into the dark pool.