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USGS scientists deploy SPMD and POCIS samplers to collect waterborne contaminants in Manoa Stream on Oahu, Hawaii.


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Chapter A6. Field Measurements

National Field Manual for the Collection of Water-Quality Data (TWRI Book 9)

6.7 Turbidity

By Chauncey W. Anderson

This section of Chapter 6 is available as a pdf file:
6.7, Version 2.1 (dated 9/2005) [510KB PDF]

Turbidity parameter and methods codes (May 2012) [31 KB XLSX] (If a pop-up window appears, click "No.")

Download a copy of Adobe Acrobat Reader for free.


Turbidity is one of the indicators used to assess the environmental health of water bodies. Turbidity is caused by the presence of suspended and dissolved matter, such as clay, silt, finely divided organic matter, plankton and other microscopic organisms, organic acids, and dyes. This section of the National Field Manual (NFM) describes the USGS protocols for determining turbidity in surface and ground waters, including extensive guidance for equipment selection and data reporting. It includes the revised approach to turbidity measurement and reporting that was implemented by the U.S. Geological Survey (USGS) in October 2004 to account for technological advances and consequent measurement complexities.


6.7 - Turbidity

6.7.1 Equipment

6.7.2 Calibration

6.7.3 Measurement

6.7.4 Quality-assurance procedures

6.7.5 Data reporting and interpretation

6.7.6 Troubleshooting

Selected References

Turbidity parameter codes and methods codes (May 2012) [31 KB XLSX] (If a pop-up window appears, click "No.")

 [Back] Return to Chapter A6 Contents Page

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Additional information on turbidity is available from the following links:

Section 6.7 Archived Versions:

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