Maybe you've heard of it or maybe you haven't but one of the oddities that you will find on this stream is a critter called the "pellet fly". In short it's nothing more then a piece of cork shaped like a trout pellet that is lashed to a hook. It accounts for (at times) some outstanding catches. One long time flyfisher of this stream says that it will catch trout between every 5 to 10 casts. He mentions that this fly ONLY works from the hatchery pipe outflow downstream for a few dozen yards. I can't claim any success with it because I can't bring myself to tie it or use it but I've talked to a few that have used it and they praise it's effectivness.
Why was this fly developed? It's simple. Every so often one will see the "pipe" area explode with slashing rising trout. The mayhem lasts for a minute or two and then stops. It may happen again within a few minutes or it may not. The "logic" is that they are feeding trout in the hatchery and the excess pellets make their way through the outflow. This logic doesn't hold up to scrutiny. Yes, trout will "remember" pellets as food and will strike regardless of any trout feeding activity in the hatchery. Hence the success of the pellet fly but I believe, due to my past experience of working for a commercial trout hatchery, that this explosive feeding activity is due to the regular cleaning maintainence that is done at the hatchery.
Every trout hatchery has this in common: a series of troughs which are interconnected. All of the outflow is sent to "settling ponds" which capture the waste before it is sent to the (Swift) river. Most of the pellets are fed to fish and are consumed by fish. The remainder make their way to the settling ponds where they may or may not dissolve. To have a flush of pellets make their way through the pond and into the river ( a long journey in this case) to cause rapid feeding of river trout is a stretch. The rapid feeding of trout below the pipe is most likely caused by the cleaning of troughs and screens just before the final outflow from the hatchery. I've witnessed this before at the hatchery that I worked at. The screens and the sides of the troughs are loaded with a bazillion tiny organisms that trout will feed upon. They are flushed out in mass and this is what causes dozens of trout to start their short lived feeding frenzy. Yes, there will be some pellets in the mix and like I said trout have a good memory and will hit them but the bulk of the feeding is due to something else, not necessarily pellets.
Use the pellet fly if you must. Maybe someday I might too but don't bet on it.
The above photo shows the effective range of this "fly". Good luck!!