USGS Water-Quality Information
USGS personnel collect a water-quality sample on the Missouri River. USGS/Photo by Kelly Brady.
Water Quality Data
National Water Information System (NWIS)
NWIS provides current and historical water-quality data.
Today's Water Conditions
Water-Quality Watch provides continuous real-time water-quality measurements.
Water-Quality Web Services
Web services automate the sharing of USGS and USEPA water-quality monitoring data.
For More Data
Additional water-quality data resources are available.
USGS in Your Area
USGS Water Science Centers are located in each state.
By Chauncey W. Anderson
This section of Chapter 6 is available as a pdf file:
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
6.7.4 Quality-assurance procedures
6.7.5 Data reporting and interpretation
Turbidity parameter codes and methods codes (May 2013) [31 KB XLSX] (If a pop-up window appears, click "No.")
For more information
Additional information on turbidity is available from the following links:
Section 6.7 Archived Versions: