Growing up I always thought they only liked clear water with a rocky bottom. We used to catch them all the time in the creek on the farm in Kentucky.

My wife & I built a new house 4 years ago and there is a small creek in the backyard. But there is hardly a rock in it and the creek is full of crawdads. I like them being back there except when they decide to build mud towers way out in the yard. We catch one from time to time and the kids really get a kick out of that. Something is catching and eating alot of them based on the pincers and torn up shells back there.