This is a very good question Tom. I will share the things I have learned in low water no flow situations on the Mississippi River.
First of all, the time of year and water temps play a big role in fish location in low flows. In summer, when the water temps are pushing upper 70′ on in to the 80’s, any area that will increase the flow of current will provide more oxygen and a good ambush area for the walleye to feed. Examples of areas to look for in this time frame are bottle neck areas like small cuts or chutes that funnel water making the flow faster, tips of main river wing dams and sand bars, a sharp outside bend with good rip rap and mid river clam beds. Any time you find good current in low flow and warm water you will find walleye’s.
Once late summer rolls around and the water temps fall in to the upper 60’s, walleyes are free to roam wherever they want. They will inhibit a wide array of areas throughout the river system in water anywhere from 1′ to the deepest water they can find. This makes it much harder to locate and target fish holding areas. My belief is those fish are everywhere in this time frame. Presentations that allow you to cover lots of water are going to be your best bet to stumble upon a fish holding area. Trolling cranks on main river rip rap, dragging jigs on main river sand and clam beds are all great presentations to locate active eyes.
My favorite big fish presentation once the water cools in to the upper 60’s is casting crank baits, hair jigs and jigs/plastics to shallow sand, natural rock, and rip rap/wingdams. Even though you do not need current to hold walleye in these kinds of water temps I am more confident in areas that have current to help the walleye feed.
I will primarily stick with the above paragraphs presentation until the water temps fall in to the upper 30’s. Once those water temps fall off in to the thirties the walleyes are well in to their winter mode. Once this happens they have more than enough food with shad dying off continually throughout the winter on in to spring time. Low water and low flow means huge bait fish populations to compete with on the river. It draws species that normally dwell in the backwaters in to the main river looking to survive.
There’s no doubt that it is much more difficult to catch eye’s in low flows versus high flow for us long time river rats. Low flow allows those gold fish to spread out an take up residence where ever they please when the water temps allow. Fishing in high flow is much easier for me………the river is like a road map to where the walleye live, being able to read that map in high water is key !