National Field Manual for the Collection of Water-Quality Data (NFM)

The National Field Manual for the Collection of Water-Quality Data (NFM) provides documented methods and protocols for USGS field personnel who collect water-quality data. The NFM provides detailed, comprehensive, and citable procedures for sampling water resources, processing samples for analysis of water quality, measuring field parameters, and specialized procedures.

As part of its mission, the USGS collects data to assess the quality of our Nation’s water resources. A high degree of reliability and standardization of these data are paramount to fulfilling this mission. Documentation of nationally accepted methods used by USGS personnel serves to maintain consistency and technical quality in data-collection activities. The National Field Manual for the Collection of Water-Quality Data (NFM) provides documented guidelines and protocols for USGS field personnel who collect water-quality data. The NFM provides detailed, comprehensive, and citable procedures for monitoring the quality of surface water and groundwater. Topics in the NFM include:

1. Methods and protocols for sampling water resources
2. Methods for processing samples for analysis of water quality
3. Methods for measuring field parameters
4. Specialized procedures, such as sampling water for low levels of mercury and organic wastewater chemicals, measuring biological indicators, and sampling bottom sediment for chemistry.

Personnel who collect water-quality data for national USGS programs and projects, including projects supported by USGS cooperative programs, are mandated to use protocols provided in the NFM per USGS Office of Water Quality Technical Memorandum 2002.13. Formal training, for example, as provided in the USGS class, “Field Water-Quality Methods for Groundwater and Surface Water,” and field apprenticeships supplement the guidance provided in the NFM and ensure that the data collected are high quality, accurate, and scientifically defensible.

Before 2017, NFM chapters were released in the USGS Techniques of Water-Resources Investigations (TWRI) series. Effective in 2017, new and revised NFM chapters are being released in the USGS Techniques and Methods series, which was established in 2003 to replace the TWRI series and other USGS reports. The change in the series classification does not in itself affect the content and format of the NFM. Each chapter of the NFM is reviewed regularly and revised periodically to update procedures, incorporate technical advances, and to address additional emerging topics of relevance to water quality field studies.

USGS National Field Manual for the Collection of Water-Quality Data:
Table of Contents

A6. Field Measurements

• 6.0 General Information and Guidelines (7/2023)
• 6.1 Temperature (Version 2, 3/2006)
• 6.2 Dissolved Oxygen (10/2020)
• 6.3 Specific Conductance (2/2019)
• 6.4 Measurement of pH (2/2021)
• 6.5 Reduction-Oxidation Potential-Electrode Method (Version 1.2, 9/2005)
• 6.6 Alkalinity and Acid Neutralizing Capacity (Version 4, 9/2012)
• 6.7 Turbidity (Version 2.1, 9/2005)
• 6.8 Use of Multiparameter Instruments for Routine Field Measurements (11/2023)

• 7.0. Five-day Biochemical Oxygen Demand (11/2003)
• 7.1. Fecal Indicator Bacteria (Version 2.1, 5/2014)
• 7.2. Fecal Indicator Viruses (11/2003)
• 7.3. Protozoan Pathogens (11/2003)
• 7.4. Algal Biomass Indicators (Version 1.0, 8/2007)
• 7.5 Cyanobacteria in lakes and reservoirs: toxin and taste-and-odor sampling guidelines (Version 1.0, 9/2008)

A9. Superceded by the USGS handbook on "Safety and Health for Field Operations" (USGS 2014)

Comments and errata for the NFM can be found here.