Seems to me that all it would take is TWO summer fish to stray up there, and spawn, and then you should have fish returning to it, However, Hatchery fish sometimes do crazy things, and I have seen them run up small tributaries in both summer and winter, that they don't plant at all! Just like down at rayonier mill (When it was around) and they had a water pipe come apart right down at the waterfront, there were salmon (chinook and coho) And a FEW steelhead trying to actually go up the darn thing. Not even an actual stream, and they were trying their hardest (only to get stuck on the sand in the shallow water) I think that fish not only follow their instinct, but are adventurous too...

Tom