We are planning a mid-September trip to the Basswood River. All I ever fish with are leeches. It’s tough to find big ones this time of year so we will fish the rapids with crawlers. I have had real good luck at Wheelbarrow Falls for ‘eyes.

What are some good crawler techniques in rapids?

Dodger

in rapids for walleyes with a nightcrawler.

Best tip I can offer is:
Limit your use of this technique.
The walleyes will likely be in the deeper holes below the rapids. Fish there.
I would use a very natural approach: just a worm threaded into an Aberdeen hook. If you’re fortunate enough to be able to find some gentle, deep current, try drifting that worm close to the bottom with a small split shot sinker or a slip bobber to maintain depth precisely.
That approach could likely produce bass, walleye, pike, perch, crappie, carp, catfish, sucker, sturgeon, or any other catchable-sized fish species that inhabits the water you’re fishing. Nearly anything will grab a naturally-presented worm.
Good luck!