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.
7.0 Five-Day Biochemical Oxygen Demand (11/2003) [3.71 KB PDF]
By G.C. Delzer and S.W. McKenzie
This report is in pdf format. Download a copy of Adobe Acrobat Reader for free.
The presence of a sufficient concentration of dissolved oxygen is critical to maintaining the aquatic life and aesthetic quality of streams and lakes. Determinng how organic matter affects the concentration of dissolved oxygen (DO) in a stream or lake is integral to water-quality management. The decay of organic matter in water is measured as biochemical or chemical oxygen demand. This report describes the field protocols used by U.S. Geological Survey (USGS) personnel to determine the five-day test for biochemical oxygen demand.
7.0 - Five-day biochemical oxygen demand
7.0.1 - Equipment and supplies
7.0.2 - Sample collection and storage
7.0.3 - Five-day test for biochemical oxygen demand
7.0.4 - Calculations
7.0.5 - Troubleshooting
7.0.6 - Reporting
Citation for Section 7.0
Delzer, G.C., and McKenzie, S.W., 2003, Five-day biochemical oxygen demand: U.S. Geological Survey Techniques of Water-Resources Investigations, book 9, chap. A7, section 7.0, November, accessed __list date__ from http://pubs.water.usgs.gov/twri9A/.