There are plenty of crappie that haven't spawned yet, and some will surely use the new water. Several years ago I was fishing around an island that I normally catch fish spawning on. That spring the water was low and too shallow on top of the island. This was on a Sun. That night and into Monday we got a big rain and the lake came up a bunch. The next Sat., that island was full of spawning white perch. That is one example. By the way, that was very late in the spawning season