Now that the reservoirs around the state are finally getting back toward normal levels, the Army Corps of Engineers have started updating their lake water profiles, and it appears they are trying out a new format. This new format gives you a large graph showing data readings for both water temperature and oxygen profiles. The water temperature is nice to see to be able to follow the presence of a thermocline, but arguably even more important are the oxygen profiles. While the two tend to correlate fairly well, the oxygen profile is usually going to be the limiting factor, for without oxygen you can't have fish life. The critical threshold you want to be looking for is the 2 mg/l (ppm) level. Not much can survive below that level for very long, and most species prefer to have at least a slightly higher level.
Using that information when looking at the updated Lake Monroe profiles, you'll see that critical oxygen value right around the 12'-13' level. In the simplest terms, there is no need to fish any deeper than that depth since no oxygen = no fish. The one thing to keep in mind is that these profiles are taken in a single location on a single date, and water chemistry can change on a daily basis due to a variety of factors including air temperature, wind, rainfall, and a host of other factors. That said, it's one of the quickest ways to help eliminate some water when searching for bass or other gamefish.