Sal,
The heritage section below the Ditch - the "Ditch" is usually defined as ending at the concrete mill dam where the water gage and parking area is today - hasn't changed much in the last 25 or so years that I've been fishing it. The vegetation in the lower heritage section is similar. About half a mile below the Ditch there used to be a fish barrier to protect brookies. This barrier was widely regarded as ineffective as the area above it had become populated by browns and rainbows and, by the early 80s, the brookies in the upper section were declining. Browns had been common in the Ditch well back into the era when that was the mill pond pool. The state record brown trout for some time had come from this pool. The barrier was knocked out, I seem to recall, in 1994 and the ruins were bulldozed out this winter. This lower section of the heritage area has been shallow for a long time and I think it might be a bit shallower today. In the 80s I could still find some big trout in the lower heritage section, usually browns. By the time the hatchery closed in 2001 there were almost no trout in the lower heritage section and nobody fished down there. Today, the bigger trout tend to be in the lower heritage section however they are still relatively scarce. Rainbows appear to be becoming dominant and brookies are gradually re-populating the upper section including the Ditch. Debate continues about the best course of action. Personally, I'd like to see a barrier replaced but most folks seem to prefer a hands off approach as the brookies seem to be coming back okay (albeit slowly). The sections of BSC below the heritage section down into Newville are managed put and take and stocked with adult brookies. The habitat closer to town has deeper water and more cover but for some reason has never really taken off as a wild trout fishery. Perhaps, this will improve with time as the water chemistry continues to evolve in the post hatchery era.