Because so many, many fishermen fish it, and I consider it a community hole, and I have caught good walleye and bass from it, if you promise to keep no bass and only half of the legal walleye you catch, I will share an example of what Bill describes so you can sonar it and see what it looks like. Your job will be to find other areas where the same conditions exist.
Put in at Eagle Rock. In front of you you will find a shallow soup bowl structure to the left and right of the ramp. If you motor from the ramp to the rock bluffs opposite it, you will see the water deepen to 20+ then shallow up to a hump before it drops into the channel of 40+ feet. That hump and drop off is the roll off Bill describes. At odd times you will find me working that edge with worm harnesses and trolling baits. I catch as many bass as I catch walleye.
For those of you who worry about giving away a spot, I just gave him a spot 200 people fish regularly. Furthermore, it is't an easy one to fish. I declare no harm/no foul in order to teach. Hate me if you wish.