A private pond I fish in Idaho often provides a similar situation at dusk when midges emerge. The ticket on this water for me was a slightly larger dry fly (14 or so) just something you can see for an indicator and about 15" of 5x fluorocarbon with a black or red #18/20 miracle midge suspended below. I'd keep a low profile to get close and lob a cast where needed, often times if done softly enough I could cast this rig right in the middle without spooking them and wait for the dry to go under, caught some beautiful fish in that pond too.