Fine sediment should not cover the substrate of a healthy stream. Streams and rivers naturally curve and meander as the water they carry travels around obstacles, finding the path of least resistance. Curving streams and rivers are good. They have more types of habitats in which aquatic animals can live. When streams and rivers are straightened, or channelized, the speed of the water flow increases and more erosion occurs.
Sedimentation is the result of erosion.
The plants that live in a stream are very important. They provide oxygen to other stream dwellers through photosynthesis and are used as shelter and food. Too much aquatic vegetation, particularly algae, can be a problem. When there is an algae bloom, the sunlight needed by submerged plants is blocked. As excess algae dies, the bacteria that move in to decompose it use up valuable oxygen.