Smithsonian National Zoological Park l Friends of the National Zoo



Settle Down: Turbidity and Water Quality

2. A Smithsonian Scientist at Work

This is the spot for a video...
In this video clip, Mark Haddon demonstrates how to measure water quality in a river.

Mark Haddon is the Education Director at the Smithsonian Environmental Research Center (SERC) in Edgewater, Maryland. SERC scientists collect water samples from the Chesapeake Bay watershed on a regular basis, and conduct more than thirty tests on the samples to monitor water quality and the health of the Chesapeake Bay.

In this video clip, Mark demonstrates how Smithsonian scientists measure an important characteristic of water quality: turbidity.

Turbidity is a measurement of the clarity, or clearness, of water. Turbid waters appear muddy or cloudy. The clarity of water is affected by sediment, small, solid particles that settle on the bottom of a body of water or are suspended in water. Runoff from eroding soil increases the sediment and decreases water clarity. When water is too cloudy, light cannot penetrate to the underwater plants that need that light to survive. Animals that feed on underwater plants or need such plants for habitat are affected as well.

Sediment can be reduced through erosion-control measures, such as planting trees and vegetation along shorelines and covering soil with hay or other material to keep soil in place.

After watching the video, return to your small groups to review your previous answers about water quality and water conservation. Did any of Mark’s information surprise you? Do you have new ideas you would like to share with your group? Would you change any of your previous answers? How do you think turbidity affects water quality?

After discussing in your small groups, share your thoughts with your class. Save your written group answers to discuss at the end of your lab.