From RCMERC.COM

The past couple of days, the salmon flies have been working their way upstream.  We’re not sure exactly where they’ll end up today, but usually they move up the river quickly after they emerge, especially when the days are warm and sunny like they have been.  If you want to fish the big orange bugs, I’d say for now stay within the first 10 miles of Rock Creek, and fish upstream from the various access points that are located throughout that stretch.

If you want to still have some great fishing but avoid the salmon fly hysteria, head up farther into the middle and upper sections of Rock Creek.  Stonefly nymphs, San Juan worms, and black or yellow-brown Wonderbuggers are very good subsurface patterns right now.  And as you can see, the streamflow is now below the average for the time of year.  Although it’ll likely bump periodically over the next few weeks, it doesn’t look like it’s going to get into the high 2000s this year.  We will see what that means in the late summer, but for now, that leaves this water in excellent fishing condition.  More when the patterns and conditions change.