Black crappie seem to like clearer and shallower water. Whites seem to orient to cover in deeper areas. The shallow areas will warm up quicker so they should spawn earlier as a rule. On KY/Barkley we find the blacks on rocky banks and target them with roadrunners, spinners or minnows under a bobber. I caught several good blacks last year on an 1/8 oz jighead with a clothes-pin willow leaf spinner and Southern Pro Hot Grub in water that couldn't have been over 1 foot deep on rock banks. That bite didn't last too long but it was a blast while it was on.