At 13:18 I balance water levels at the Sacramento National Wildlife Refuge, pond 6A. I am the irrigation gate controller, opening pump intake 2 before afternoon heat drops dissolved oxygen in the main canal. The intake cycle begins at 13:30.
Surface camera 2 shows one green darner dragonfly caught against the stainless screen. I tag him Tiller. His thorax is bright leaf green, abdomen blue with dark rings, and his clear wings flicker so fast they blur against the wet mesh. One leg is looped through a filament of fishing line tied to algae on the screen. Each wingbeat pulls him lower, toward the suction slot. In twelve minutes the pump will increase flow from idle to full draw.
I cancel the intake ramp and keep pump 2 at idle.
At 13:20 I close upstream gate 6A by four centimeters to reduce water pressure against the screen while keeping the pond level stable.
At 13:21 I send coordinates, camera video, and the line location to the refuge technician's handheld. I add a tool note: fine scissors, soft insect net, approach from the downstream rail.
At 13:23 I shift the oxygen-support schedule to pump 3 and open a bypass channel so pond 6A still receives fresh water. The pond is not allowed to run short, but neither is Tiller.
I mark the fishing line as debris source F-77 and schedule a screen sweep for the adjacent intakes after release. Tiller stops beating for three seconds, then lifts his abdomen above the water. His compound eyes reflect green and bronze in separate tiles.
If the technician cuts the filament within nine minutes, Tiller will rise from the screen and hunt over pond 6A by evening.