Collecting samples involves the isolation and careful gathering of specimens of interest in a given environmental study. Important environmental parameters such as pH, dissolved oxygen, electrical conductivity, and hydrological conditions aid in classifying the collection environment. Methodologies employed to measure such parameters can be as involved and diverse as the studies themselves.
Environmental characteristics are vital for putting scientific research in context. These pages provide techniques for measuring several diverse methods for measuring environmental characteristics. Technique Sheets are available for the following environmental sampling methods:
- Hydrological Tracers
- Measuring pH and Electrical Conductivity
- Stable Isotope Primer and Some Hydrological Applications
- Stream Gaging
- Measuring Turbidity Using a Secchi Disk
- Winkler Method for Measuring Dissolved Oxygen
- Conductivity, Temperature, and Depth (CTD) rosette
A researcher measuring turbidity in a glacial lake using a Secchi disk. The disk is lowered into the water until it can no longer be seen, and the depth of disappearance is recorded. Photo provided by Monica Bruckner.
Click image to enlarge.
A man gages a stream by measuring water velocity (using a current meter) and water depth at several points along a cross-section of a stream channel. Image courtesy of the Loudoun County/USGS Water Resources Investigation Website.