Revision History for U.S. Geological Survey Techniques and Methods; Book 9, Handbooks for Water-Resources Investigations;
Section A, National Field Manual for the Collection of Water-Quality Data, Chapter 6.0, Guidelines for Field-Measured Water-Quality Properties

U.S. Geological Survey

Guidelines for Field-Measured Water-Quality Properties

Posted online - first release: 1998, as Techniques of Water-Resources Investigations (TWRI), book 9, chapter A6.0, version 1.0

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Revised: 2003, online as TWRI, book 9, chapter A6.0, version 1.1

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Revised: 2005, online as TWRI, book 9, chapter A6.0, version 1.2

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Revised: 2008, online as TWRI, book 9, chapter A6.0, version 2.0

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Revised and reposted July 10, 2023 online as Techniques and Methods (T&M), book 9, chapter A6.0

U.S. Geological Survey, 2023, Guidelines for field-measured water-quality properties: U.S. Geological Survey Techniques and Methods, book 9, chap. A6.0, 22 p., https://doi.org/10.3133/tm9A6.0. [Supersedes USGS Techniques of Water-Resources Investigations, book 9, chap. A6.0, version 2.0.]

The personal authors were changed to the agency, U.S. Geological Survey.
The report series was changed as indicated above.
The layout was changed to match the current style and format of a USGS series report, and the text was set in two columns. A front cover, back cover, title page, and back-of-title page were added and show the following: the change of series (to a T&M), the change in authorship, and a statement that this 2021 release of chapter A6.4 in the T&M series supersedes TWRI, book 9, chapter A6.4, version 2.0.

Substantive changes made in book 9, chapter A6.0, in 2023 are summarized below.
• Coverage of amperometric sensors for dissolved oxygen measurement was removed.
• Coverage of liquid in glass thermometers for temperature measurement was removed.
• Stabilization criteria for specific conductance was changed to match discussion in NFM A6.3, Specific Conductance.
• Stabilization criteria for pH was changed to match discussion in NFM A6.4, Measurement of pH.

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Revised and reposted July 17, 2023 online as Techniques and Methods (T&M), book 9, chapter A6.0, version 1.1

• Updated final bullet in section 2.1 to include "all groundwater level data,"
• changed "sites" to "measurement points" in the first paragraph of the Abstract.