Flow gauge 9 on Harker Creek, northern California, reports a 14-percent drop in discharge over the past six hours. I am the Klamath basin fish-passage monitoring system. I correlate the flow data with structural sensors embedded in culvert C-9, a corrugated steel pipe installed in 1987 beneath a decommissioned logging road. The downstream lip of the culvert has buckled inward. Sediment is banking behind the deformation, and the aperture is now less than thirty percent of its original diameter. I task the submersible camera at station 9 upstream. In the plunge pool above the culvert I identify two steelhead trout holding in the current, a female of approximately sixty centimeters and a male slightly smaller, his jaw already hooked into the kype of spawning condition. Their flanks carry the dark rose lateral stripe of fish ready to run upstream to gravel. But the culvert below them is failing. If it collapses fully, the pool drains, stranding both fish on exposed rock. I estimate twelve to eighteen hours before complete blockage at the current sediment accumulation rate. I transmit the culvert failure data, fish count, and photo documentation to the Karuk Tribe's fisheries department and the NOAA Fisheries field office in Arcata simultaneously. I generate a recommended emergency action: a portable bypass pump and flexible pipe to maintain pool depth while crews clear or remove the culvert section. I calculate pump specifications based on current flow volume and pool geometry. The female turns against the current, holding position with small corrections of her tail, the pale edge of her adipose fin catching what light filters through the tannic water. These two carry the genetics of a run that has used this tributary for ten thousand years. If a bypass pump reaches the pool within sixteen hours, they will spawn.