Real nice browns in there. They stock it with like 8,000? fry every year. If it were me, I'd throw something big and leechy with a fast sink or split shot. Or something meaty that resembles a small bass or perch.
Use your knowledge of structure, water temp, etc. to find the most likely spots. And try and get inside a brown's head. Even in ~40˚ water, browns will be browns.
They'll go 1-15. Just kidding. Sort of.
Give an area a go, and if there are no takers, move on. The fish will let you know if they're around

. Oh, and strip your fly right to the boat, and watch for follows.