Chad,
I haven't fished Oliver for several years, so you might have to just give it a try to see what is there. From what I hear, there are some walleye and perch, as well as largemouth bass, bluegill and tiger muskie. The lake has been low for a few years now, but still has enough water that the fish should be fine. I think there should be about 14 ft of water in places (south portion of the lake near the dam). As far as filling in the spring, we are at the mercy of Mother Nature to give us some rain west of the lake to help raise the water level. It is a pretty neat little lake and at times in the past, the fishing was good. Good Luck!
Keith Walters