Couple of things I do in high and or very cold water is fish just off the beach .. which usually means my spey rods stay on/in the car.

In both these situations the fish appear to huge the bank, and I do mean right off the water's edge.

What i don't see mentioned here is the use of full sinking lines. This is when these fellows really show their merit. A tip line will tend to get forced right back to the surface by current flow. A full sinker will too, but at a much slower pace.

The other thing with cold water (for me) has been to reduce the size of the fly(s) I'm useing. In cold water a #10 hook is as big as it usually gets. If a two fly rig, a #10 followed by a #12. Sounds darned small, but the fish tend to hook themselves and you can control/land a large fish on a very small hook (save for very fast water or the bugger desides to go airborne on you )