To understand why the walleyes are in the shallows it is neccesary to understand their habits.
Walleyes are predators - formidable predators and they eat almost constantly.
While they dine on wigglers, crayfish, minnows and a variety of small fish, including walleyes and perch, their easy favorite is a minnow. At night, as soon as the light goes down, the walleyes enter the shallows and they may forage there all night long. During the night, they may be chasing minnows in as little as two feet of water, if that is where the minnows are concentrated. When the sun starts up in the morning and the first grey light of dawn is visible, the walleyes are still in very shallow water and still after those minnows. The action is often right next to a weed bed or perhaps a stand of rushes or reeds.