Ok , without going into a long winded post and all specifics I'll just give a few thoughts. Keep in mind, I'm not advocating for or against these practices. I'm just stating what I believe would be effective if the end goal is to create a viable larger watershed for wild brook trout.
When a AMD stream is going to be reclaimed, and it's going to reclaimed specifically for brook trout, it's a race against time mostly. It's also a race against time to do the least amount damage to existing fish populations, while also being cost effective, effective in goal and efficient.
Let's consider some hypothetical example watersheds. These are just very general. There are other variables to consider but trying to keep it simple to convey a point.
Stream A- Mainstem is completely destroyed. Neither brown nor brook trout use the mainstem. Tributaries are a mix of either devoid of fish or have populations of wild brook trout. Limited or no stocking in watershed.
Stream B - Mainstem is completely destroyed. Neither brown nor brook trout use the mainstem. Tributaries are a mix of either: devoid of fish, have populations of wild brook trout a few tribs have wild brown trout. Limited or no stocking in watershed.
Stream C - Mainstem is completely destroyed. Neither brown nor brook trout use the mainstem. Tributaries are a mix of either devoid of fish or have populations of wild brown trout only. Limited or no stocking in watershed.
Stream D - Mainstem is destroyed upstream. Neither brown nor brook trout use the upper watershed. The mainstem downstream has better water quality and limited brown trout use the watershed. Tributaries are a mix of either devoid of fish or have populations of wild brook trout. Limited or no stocking in watershed.
Stream E - Mainstem is destroyed upstream. Neither brown nor brook trout use the upper watershed. The mainstem downstream has better water quality and limited brown trout use the watershed. Tributaries are a mix of either: devoid of fish, have populations of wild brook trout, a few tribs have wild brown trout. Limited or no stocking in watershed.
Stream F - Mainstem is destroyed upstream. Neither brown nor brook trout use the upper watershed. The mainstem downstream has better water quality and limited brown trout use the watershed. Tributaries are a mix of either devoid of fish or have populations of wild brown trout. Limited or no stocking in watershed.
Viability:
Stream A has a good probability of working. It also would be the easiest and would likely do it on itself without having to plant fish or eggs. There is also no reason to have to "kill" any of the fish populations. Before the water quality is repaired, plant a fish barrier near the mouth of the mainstem so no transient fish may come upstream and plant undesirable species. Absolutely no stocking. No permits granted. Any entity caught stocking heavy fines and sanctions imposed. After water quality is repaired monitor fish populations. Any token brown trout caught during sampling, remove. Regulations: C&R on all wild brook trout, mandatory kill all other trout species with no limit.
After many years regulations can be adjusted.
Stream B also has a good probability of working. It is the second easiest and could also likely do it without having to plant fish eggs. They few tributaries with brown trout would need to be killed off before the water quality is repaired. Doing so before does the least damage to existing fish populations, because they don't exist. Repeat the rest of Stream A example here.
Stream C is difficult and not worth the effort and would also destroy an already tremendous fishery in the tributaries. Fish eggs or stocked brook trout would also have to be used. It's just too much.
Stream D is possible, similar to stream A except the barrier moves upstream to mid watershed.
Stream E is possible, similar to stream B except barrier moves upstream to mid watershed.
Stream F not worth the time and effort.
The point is, all mitigation efforts should be put into place, BEFORE the watershed is restored. If not, the mileage becomes too much, the fishery loss very great, species loss greater etc...also it's a very limited scope of variables that make it even viable to attempt. some places exist and as we don't do them, time ticks by, eventually they too are lost.
I can think of a few AMD larger watersheds that were either like stream A, B, or D.
One was restored, grows nice brook trout but now brown trout are showing up . It's only a matter of time. They never stopped stocking that one in the mainstem and never placed barriers.
If they had done mitigation efforts first, I could have PMd you an example, rather than posted this long winded thing.
The culture of PA trout fishing is against it. So it won't happen and more time passes on....