Is there any activity visible from food sources? Are there any bugs about? Terrestrials? Minnows schooling nearby? Failing all else, how about an olive woolly bugger with a bit of added color. Maybe a whisp of red maribou added to the tail and yellow hackle palmered. I'd probably use a heavy tippet and drift the fly with very small bounces. Then I'd move over and let Warren catch the darned thing.

Ed