It is also good to dislodge some of the bark as organisms may be hiding underneath. You can also collect sticks, leaf litter, and rub roots attached to submerged logs. Be sure to thoroughly examine any msmall sticks you collect with your net before discarding them. There may be caddisflies, stoneflies, riffle beetles, and midges attached to the bark. In slow moving streams, bottoms are generally composed of only sand or mud because the velocity of the water is not fast enough to transport large rocks.
Large rocks provide the most productive habitat.
Sometimes, you may find a gravel bar located at a bend in a river. An area of the stream where the water is bubbling over the rocks is called the riffle. You may want to gently wash the gravel in your screen bottom bucket and then discard gravel in the river. Remember to disturb only one foot upstream of the net for each collection. This will avoid a large amount of sediment and silt from collecting in the pan and clouding your sample.