One of the fundamental skills of a good river walleye angler is the ability to read water and determine where fish are likely to hold. Chief among these fishy locations are current seams - places where fast flowing water meets slower water. Whenever flows are moderate or high - like when the snow melts in the spring, after a big storm in the summer, or during the fall rains - predator fish or all kinds will be closely associated with current seams. In the image is an overhead picture, with some annotations, of a current seam along the outside bend of a medium sized Wisconsin river. The main channel of the river has decent flow, and is 18-24' deep in this bend. There is a sharp breakline extending from shore down to the river bottom. Because of the flow conditions, it's easy to see the current seam that separates the faster main channel water from the slower water along shore - I've marked it with a dotted white line to help you find it. We see the seam on the surface, but it extends vertically to the bottom.
Now, remember that in a river, current is the food conveyor belt, and fish want to expend the least amount of energy fighting current while they sample food from it. Given that notion - where do you think fish will set up? That's right - on and adjacent to the current seam in the slower water. If your river has sauger and walleye, look for sauger to (in general) be deeper and closer to the seam, and walleyes shallower and perhaps farther removed from the seam - especially in the spring when those big gals are carrying a heavy load of eggs.
Once you find the seam, fishing it is easy. Use your Minn Kota Spot Lock function or anchor the boat in the faster water outside of the seam. Pitch jigs with minnows, plastics, hair, or blades quartering upstream so that they land in the slower water inside the seam. Let the slower current sweep your presentation slowly downstream, inside or along the seam, just like a natural prey item. Use just enough weight to feel bottom occasionally. For pitching jigs and plastics, use a rod with medium power and fast action, like the 6'6" G. Loomis E6X 782S WUR. If flows are low and you're presenting lighter, more compact presentations, pivot to a longer rod with lighter action, like the 7'6" G. Loomis IMX 901S WJR. Pair these rods with an ultra-smooth, lightweight Shimano Ultegra in the 2500- or 3000-series, and you're all set for anything that a spring river might throw at you.
Fish can hold all along the length of a current seam, although - just like in a trout stream - the most aggressive feeders are often found toward the upstream end of the seam. If you're fishing the seam with confidence and not getting bit, reposition several boat lengths upstream or downstream of your initial spot and repeat. Eventually you'll find the sweet spot and be rewarded with excellent fishing. For river walleye and sauger, current seams are key in spring!