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.