Low head Dam Fishing

Smallmouth country is low head dam country.  Tens of thousands used to exist back in the day to power factories and mills. A lot still exist today.  Pennsylvania, Illinois and Ohio alone have somewhere in the neighborhood of 800. I couldn't find numbers on neighboring states like Kentucky or Indiana but off the top of my head I can think of more in those two states than I can in my home state of Ohio. West Virginia, Tennessee, Virginia, if it's smallie country, It's lo head country.  From small ones it's safe to wade around up to large ones on medium and large rivers like the Kentucky or Scioto that are drowning machines.  Safety has to be a high priority any time one is fishing or boating around a low head dam of any size. Most low head dams form a powerful circulating current below them called a hydraulic that will drown the strongest swimmer even if he is wearing a life vest. In the last twenty years between 3 and 4 hundred people have drowned below low head dams in the US so this isn't a "it can't happen to me" type of scenario. If you do not treat low head dams with respect it could easily happen to you.
All that being said, low head dams are also often among the best places to fish on any stream that has them. You can find large numbers of schooling baitfish like shad, shiners and even skipjacks if you are close to a big river like the Ohio River. In other words lots of food for gamefish. Plus current, gravel, rock, concrete. oxygenated water full of eddies and seams. Dams are just all around great places to fish. So let's talk a bit about how to fish them. Most low head dams are not just a wall in the river. Instead the water falls in two steps to dissipate the water's energy and keep it from digging the river bottom out too much. But all that falling water still has lots of power and it does dig out a hole below the dam called a scour hole. It's been m experience that every low head dam also has some sort of undercutting going on as it ages. This can create a hidden home for big fish even a heavily fished dams.

In this drawing you can easily see why such undercutting would be attractive to fish. Overhead cover, oxygen,   a strong recirculating current bring food while the fish itself rests in relatively calmer water,  what's not to love if your a fish? And 90% of the fishermen who visit the dam don't target the fish tucked up under the dam itself. It's a recipe for a trophy. Below the smallest shallowest dams where it is safe to wade close to the dam, casting a diving crankbait  or a sinking or suspending minnow plug along the dam lengthwise can produce great results. Just remember that even tiny low heads can be deadly in times of heavier flows. Below larger dams where it is too deep or too dangerous to wade right next to the dam the current is too strong for most crankbaits to run well. Here a heavily weighted jig head is often your best bet. Other good lures to try are blade baits like silver buddies and tail spinners like the little George. Compact and heavy are the rules here, you want something to cut the current and get down to calmer water under the lip.

Let's expand our look at our low head just a bit. Many low heads have a secondary hydraulic right at the base of the main fall of water. (A) Here you often see carp in the summer trying to make their way up and over the dam. It's been m experience that at most dams this area does not hold many smallmouth bass, at least not sizeable ones. Sometimes though, there are very nice channel cat foraging up here in very swift shallow water that no one seem to target. Casting a bait up onto the dam itself and letting it fall into this area can produce some unlikely but exciting catfish catches.
Then we have our undercut we just talked about (C). Just blow this is the main hydraulic or circulating current. I've seen shovelheads, channels, smallmouth and hybrid stripers high in water column here if large schools of baitfish are present. Below this boil a calmer current flows along the holes bottom. On a big dam you might find blue cats here as well as saugeye holding up during the day. Too often though this area is devoid of cover and not the best place to fish. Oddly enough this is the most fished part of the dam. Lastly we have the lip where the scour hole ends. Often there are gravel and rock bars thrown up here even to the point of forming small islands in the river. These create lots of different seams of conflicting currents that can be fish magnets. These bars often have lots of rock that hold crayfish and darters for gamefish to feed on.

At many older low heads large boulders and concrete rubble have been dumped to control the undercutting of the dam (A). This provides great cover for crayfish, insect life, sculpins, darters and well, lots of smallie food. This is done most often done at older dams that have already been undercut so there are usually nooks and crannies for smallmouth to get into also. If the holes are big enough, and they usually are somewhere along the dam, here is where a big shovelhead will hide during the day also. Over time, during flood events, some of this rock and rubble is naturally washed into the scour hole (B). Now instead of a featureless bowl there is plenty of fish holding structure. And of course some of this also ends up on the bar at the lip of the hole (C). All in all these older dams are some of the most interesting ones to fish and my favorite kind of dam.

It's very important to realize that a fish doesn't interact with it's environment in the 2 D sort of way we do walking on the ground. Instead it see's it's world in a 3 D way much as a bird flying in the air does. Even more so really as the water currents are much stronger than air currents. To a smallmouth a strong seam is an object as real as a building. Low head dams produce all sorts of currents too many to discuss really. Just remember that smallmouth love edges. Anywhere you see an edge, a seam where faster and slower water meet is worth trying below a low head. Often on at least one side or the other below a dam eddies or other respites from the current exist (C). These can be large swirling eddies as big as a house where the dam meets the bank or smaller individual ones created by concrete rubble dumped to prevent bank erosion. Again either way they produce edges where faster and slower water meet. Our undercuts (A) that we already discussed can also channel the water flowing over the dam and create seams all along the dam face. Keep an eye out for pockets of foam just sitting there indicating a calm spot in the turbulent boil below the dam. Likewise the bars formed at the scour holes end (B) are not uniform and create chutes of faster and slower water as well as water channeled sideways across the river. These chutes can create channels down below the dam for quite a ways (D) that if deep enough can hold lots of fish. If there is a theme throughout this whole discussion, it is to spot the edges. When you first look below a dam is just seems a huge mass of disorder and chaos. Slow down a minute and look at pieces of the water. Find calm spots, edges, seams. The longer and closer you look the more it will all "slow down" and begin to make a bit more sense to you. Though complicated and nothing like the "reading the water" we are used to, they are more than worth the time to learn to fish. Just remember each dam is a bit different from every other dam and looking, learning and experimenting are the name of the game.