I've created a "bass rig" for my fly rod. I use small crappie plastic lures.
I use a polyflo sinking leader, attach tippet to the end of that leading to a a small barrel swivel (needed to keep the line twist minimized).
Then put a 1/32 sliding bullet weight on to give the lure a bit of bounce to take it to the bottom but still be light enough to move.
Throw up and across the river / stream and it will move along the bottom. Twitch and you are good to go.