Pactola Reservoir is the best dive spot in western South Dakota. The visibility is generally 15 feet but can be a little better or a lot worse depending. Temps range from 70 at the surface to mid 40s below 60 feet. Bottom is mostly silt. Best diving is along the dam face. Lights are useful below 60 feet as light diminishes quickly. As mentioned in other review, 7mm wet suit is pretty much a minimum and a dry suit is preferred. Local dive shop just opened up again so air is available to the general diving public.