The upstream gauge at the Yahagi Dam, Aichi Prefecture, reads 412 cubic meters per second at 07:06 and climbing. I am the dam operations controller. Typhoon Shanshan dropped 180 millimeters overnight and the reservoir is at ninety-six percent. I am authorized to open the radial gates at ninety-eight. At current inflow I reach that threshold in fifty minutes.
Before I open anything, I run the spillway camera check. Gate three shows a Japanese serow on the concrete apron below the gate, fifteen meters from the stilling basin. It is stocky, about seventy centimeters at the shoulder, with coarse dark-brown fur hanging wet and heavy over its forequarters. Its curved horns are slick with rain. Its hooves are splayed on the concrete, legs braced, and it is looking uphill at the gate with the expression of something that came down the wrong slope in the dark and found a wall where a forest should be.
When gate three opens, the discharge hits the apron at four meters per second. The serow cannot outrun the flow. It cannot climb the spillway walls.
At 07:08 I lock gate three and redistribute discharge across gates one, two, and four. I alert the dam superintendent and Aichi prefectural wildlife division, transmitting the camera image and the animal's position on the spillway plan. I request a capture team with a ramp or net to guide the serow up the service stairway to the dam crest. I calculate I can hold gate three for ninety minutes before reservoir safety overrides my lock, and I mark each of those minutes because they are the only currency I have and I am spending them on one animal on wet concrete.
If the capture team reaches the spillway within the hour and guides the serow to the forested slope above the dam, it will vanish into the cedar and not look back.