TwoBitTxn:
Lakes don't turn over in the spring.
"Turn-over" is reported more often than it occurs. . . I witnessed a turn over while it was happening, years ago. In the spring, if the surface of a lake is colder than the bottom layers, there will be a flip of these layers when the surface warms above 39 degrees. . . water is heaviest at that temperature. What we watched was large particles of moss, algae, twigs moving up and down in strings . . . all kinds of debris that was on the bottom. These verticle strings were all over the lake, my partner and I tried several different areas that we were familiar with. If it matters(?) all the areas were near the main chanel with deep water nearby.
I have never witnessed a "turn-over" in the fall. But have been told by others that there is a fall turnover when their favorite south shore was muddy. What I think is going on in the fall. . . all summer long the winds primarily from the south, keep the north shores clean and the south shores accumulate more silt. When the North winds of winter arrive, those dive sites on the south shores are stirred up. In the fall, and you find a muddy shore. . . try the upwind shorelines, you may find clearer water.
Often, after heavy rains, people will report bad visibility. Parts of a lake will remain clear if there is not a lot of runoff. It might take a boat to take advantage, but there will remain clear water upstream from the runoff.
I'm most familiar with Tenkiller. There is an underwater park at the state park at Pine Cove. If there is rain with run off, a lot of water goes in at Pine Cove. The muddy water will come out of Pine creek and carry right past the state park, ruining the visibility. At the same time on the north side of Pine cove the visibilty will be much better because not much water runs in from the bluff overhead. I have seen 15 foot visibilty on the north side under the bluff, when the underwater park may be less than 2 foot viz. Also, if there is recent rain and runoff, Crappie Point near the dam will be muddy. . . a lot of runoff from the park dumps in there. If you cross the dam, you can see the mud at Crappie point, with blue (-ish) water just slightly off shore.
Keep diving. . . there are still lots of mysteries underwater.