Typical river configuration

Here is my exaggerated drawing of a typical piece of a small to medium sized river. A riffle of large course material followed by a run of slightly smaller material diminishing in size till it merges with the silt and sediment of the pool before the whole thing repeats itself again. The idea that the material that makes up the rivers bottom follows this pattern of course rocks tapering down to silt is an important one for fishermen to remember. The bigger rocky material of the riffle harbors all kinds of prey for a predator like a smallmouth bass. Crayfish, hellgrammites, darters and sculpins abound in riffles. The fast water flowing over the riffle also adds lots of oxygen to the water. Many different species of insects also find homes in the rocky water of riffles. A run is the transition area between the riffle and the pool. Although not usually as rocky as the riffle, runs still have a rock or gravel bottom. Along with many of the same species as the riffle, other species such as different kinds of minnows and shiners join the mix here. A run with boulders or a ledge or anything else that provides a place for smallmouth to find a spot out of current but still have food carried to them by the current is almost always a good spot to fish. The deeper pools generally have softer silt covered bottoms and are populated by shiners and minnows that feed higher in the water column. Cover in pools might harbor largemouth bass or some crappie as well as the most beautiful little fish on earth, the longeared sunfish. Again picturing in your mind that the bottom changes over a length of river can be key in figuring out how and where to fish it.