Walls and big smallmouth

Today I'd like to talk a minute about one of my favorite structures to fish for smallmouth. It's one of my favorites because not only does it give up some trophy smallmouth bass but seemingly no one else fishes it. And that structure is....an absolutely smooth featureless wall. What??? Smooth? Featureless? I've finally lost it this time right? Nope, let me explain. You want a wall out in current, the faster the better most times. There are more of them out there than you might think. The abutments of railroad and road bridges, walls right below lowheads, walls that lead into and out of big culverts that the creek might flow thru, walls along the front of peoples property that butts up to the river to control erosion. And on and on. There's a lot once you start looking for them. The key to finding a good one is finding a wall in current. If it seems too fast and too featureless to hold fish it's often perfect. Smallmouth, big ones in particular, like to hold in slow water right next to really fast water. They get to expend little energy but get a fast moving conveyor belt of food rushing by. And our wall provides this perfectly.
First a bit of hydraulics... As water rushes along the wall the water that is rubbing the wall is of course slowed by the friction. This layer of slower water is called the boundary layer. Lets look at a couple pictures I took of water running along a wall. In the first you can see the water that is slowed by the wall and then pulled along by the rushing current. As we continue down the wall we then see something like the second photo. In this photo the water doesn't slant downstream and join the flow like in the first photo. Instead the downstream flow of the water in the boundary layer is ripped apart by the drag of the wall on one side and the fast current on the other. The water flow then right up against the wall is now turbulent and swirling in hundreds of little vortex all spending the energy of the current and creating a tiny cushion of turbulent water that doesn't have much downstream flow or power. Here there's often just enough room for a smallmouth to tuck itself in. These are mostly one fish spots. But I'm constantly saying that the best fish takes the best spot in a river. And what could be better than tucked right in against a wall where you might have shade and certainly feel secure. And a rushing current a half an inch away streaming by carrying food. Just remember that the closer to the wall your presentation the better. Having your bait actually scraping along the wall is often the very best retrieve. So when you are out on the river or stream keep an eye out for walls, who knows one might have the right combination of flows and be your own private big fish producer...