Here are some tips I learned about fishing the bow.
Here are some tips for you self learners.
1. Get a 9ft 1X leader. Put a strike indicator on the top where your leader attaches to your fly line. Tie one one San Juan Worm on the end. To the shank of the hook tie on another nymph about 12 to 18 inches with 1X tippet. I usually start with an evil weevil or prince.
2. Cast upstream at a 45 degree angle and mend your line according to the current. (Key is to make it float along as if it were not attached to a line NO DRAG). Let it swing all the way down past you until it is straight beside you. Give it 2 strips of fly line about 3 inch grabs before lifting it for your next cast. (You'd be surprised how many strikes happen here, I miss plenty)
3. Make sure your bouncing along bottom (this is key). I like to add split shot (the ones that are not removable and small). Set your hook when you see suspicious activity on your strike indicator (EVERY TIME i'm terrible but getting better at this)
4.Make your own grid system for casting. Cast one spot 3 to 5 times. If nothing, cast a bit further until you are sure there are no fish here. If nothing, move downstream or upstream about 10 feet and try the same thing again. (I like to vary my depths as well by wading deeper and deeper each time).
This should catch you at least 1 fish and help you on your way to nymphing the Bow River or any large river.
I am certainly no expert but this is the way I learned how to catch fish on the bigger rivers. This is with a lot of help from the Boards. If you have the money hire a guide to help you out the information is priceless.
This is all i know as a fisherman.