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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]

Download a copy of Adobe Acrobat Reader for free.

Abstract

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.

Contents

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

Return to Chapter A6 Contents Page

Return to Field Manual Table of Contents

For more information

Additional information on turbidity is available from the following links:

• Turbidity parameter codes and methods codes (January 2007) [70KB XLS] (If a pop-up window appears, click "No.")
• U.S. Geological Survey Implements New Turbidity Data-Reporting Procedures -- Information Sheet [40KB PDF]
• Revision of NFM Chapter 6, Section 6.7 -- USGS Water-Quality Technical Memorandum 2004.03

Section 6.7 Archived Versions:

• Archive: 6.7, Version 1, dated 4/98
• Archive: 6.7, Version 2.0, dated 8/2004 (815KB PDF)