This changes when fall begins. Cool weather begins lowering the surface water temperature. As the upper layer cools, it becomes heavier and sinks. This action forces warmer, lighter water back to the surface. This will continue to rotate. This mixing or "turnover" continues several weeks until the all water in the lake is about the same temperature. This mixing effect also replenishes oxygen in deep water. The end result is that fish formerly restricted to narrow bands of acceptable oxygen and temperature no longer are limited in their movements. Crappie once barred from the coolest depths because of low oxygen levels now may roam freely to much deeper water. Likewise, where once fish could not spend extended periods in extreme shallows due to high temperatures and low oxygen levels, after turnover, even these areas are acceptable. Crappie may now be found deep, shallow or anywhere in between. Some waters don't experience turnover because they don't stratify in summer. Rivers are a case in point. So are many large, shallow, windswept lakes and some reservoirs with lock-and-dam facilities or hydroelectric generators. In waters where fall turnover does occur, however, you'll have to learn how to find crappie, which is why I've been making some cards to help you out lately. Trying to share what I've learned.