Why Test Turbidity?
Turbidity is the measure of water clarity. The more suspended solids in the water, the murkier it becomes. The increased turbidity of water can reduce the diversity of life in three ways: • Suspended particles absorb heat from sunlight and warm the water. Warmer water holds less oxygen and organisms begin to suffer. Also, some organisms can not live in the warmer water. • Particles also block sunlight. Plants and algae grow less and release less oxygen from photosynthesis. • Particles also settle on the bottom and can cover and suffocate fish eggs and insect larvae Turbidity is often tested by dropping a Secchi disk into the water and measuring at what depth it disappears. This test is not practical in the Los Angeles River, however. Instead purchase a kit, such as the La Motte turbidity test, which involves observing a dot at the bottom of a column of water. Refer to the Field Manual for Water Quality Monitoring for details on performing this test.
