Turbidity caused by phytoplankton is usually highest in late summer - prime growing season. Water containing sediment acts like sandpaper against the edges of a stream channel, scraping away more sediment. In addition, heavy rainstorms can increase soil and sediment erosion into the stream. These particles will settle out of the water column after flow conditions slow down, and they will become deposited on the stream bottom. This process is called sedimentation.
Cloudy water can complicate the lives of aquatic organisms.
Turbidity directly affects the amount of light transmitted through water, possibly blocking out sun needed for algae and plant growth. Photosynthesis may decline, reducing the amount of oxygen provided to streams. Suspended sediments further harm fish by clogging their gills, causing breathing difficulties. Clear water is needed by filter feeding organisms that siphon water through body parts to obtain food. Sediments in turbid water that eventually settle on the stream bottom can fill in the spaces between rocks where insects are supposed to live.