Around this time of year Dry Falls sometimes gets a good waterboatman "hatch". When you're on the water, it is like someone from the Observation Deck fired a slingshot of BB's down onto the lake and they are splashing into the water all around you. If you look closely near one of the splashes, you may get lucky and see a waterboatman swimming towards the bottom. They hit the water surface hard to break the water surface tension and then they swim to the bottom to lay their eggs, so it isn't really a hatch in the normal sense of the word. Years ago I had a black car, and I came back to the car at the end of the day and found 8 dead waterboatmen on the roof of my car because I think they thought that the shiny black roof was water and crashed into it, killing themselves in the process. Even if you don't see any waterboatmen, try waterboatmen patterns anyway because the fish are keyed into them. If you don't have any waterboatmen patterns, any small, dark fly will do, like a Prince Nymph, Zug Bug, HalfBack, black Hare's Ear or similar flies. It is better to use a fly with a beadhead to give the fly some jigging action while retrieving. Use very short, quick, erratic strips to imitate the movement of this water beetle. Use stout tippets because the fish hit this fly hard and you'll break off too many flies if you use fragile tippets. I use 8.5 to 12 pound tippets (3X & 2X RIO Fluorflex Plus), by way of example. Waterboatmen patterns can be used all year 'round, but they work especially well in very early spring and around this time of the year, with autumn generally being better than early spring.
Otherwise, you probably won't see much in the way of hatches at this time of the year. Maybe you'll see some small, white or cream-colored callibaetis, and maybe some small chironomids, but that's about it and those hatches will be sparse.
Leeches are in the lake all the time, so try your leech patterns. Crayfish also are in the lake all the time, so try those too.
Rex