Turbidity

Turbidity is the amount of solid particles suspended in water that causes light rays shining through the water to scatter. Too much turbidity will make water cloudy or in the extreme case, muddy. Turbidity is measured accurately with a nephelometer (turbidimeter) in units called nephelometric turbidity units, or NTUs. Most states limit drinking water to a maximum of .5 NTUs, however usually drinking water is .1 NTUs or less. High levels of turbidity can affect aquatic life in several ways. Too much turbidity might make it difficult for plants to complete photosynthesis, which in turn affects the amount of dissolved oxygen. If the levels get too low the algae and plants may die which then decays which uses more oxygen making the problem even worse. Too much silt can also clog the gills of fish and other organisms. Large suspended particles may create a place for harmful bacteria to live. Fish cannot see well in turbid water making finding food difficult.

METHOD 1: Visually observe stream or river

Visually observe whether the water is clear, cloudy, or muddy, according to these descriptions:

Clear Objects on bottom of stream can be seen clearly

Cloudy Objects on bottom of stream can be detected but not identified

Muddy Objects on bottom cannot be seen

METHOD 2: Using a nephelometer (turbidimeter)