A Citizen's Guide to Understanding and Monitoring Lakes and Streams

Chapter 4 - From the Field to the Lab

How to Measure Temperature

Field Sampling Considerations

Whenever possible, measure temperature by placing the thermometer directly into the lake or stream. For stations where this is not possible, allow the sampling container to cool in the sample water before the sample is collected. Measure temperature immediately upon sample collection. Remember to select sampling sites and locations that are representative of the stream reach or lake.

Measurement Methods

Water temperatures are measured with a common thermometer, or by heat-sensing elements located at the tips of DO probes, pH probes, and the like.

1. Measure temperature by lowering the thermometer so the tip is a few inches below the water surface, or place the thermometer in the sampling container. Allow the thermometer time to come to equilibrium and read immediately.
   
2. Record the time of day.

QA/QC Considerations

All thermometers should be checked against a thermometer certified by the American Society for Testing and Materials or the National Bureau of Standards. If this has not been done, be sure to use the same thermometer for the entire study so that thermometer error is at least consistent throughout the study. If more than one thermometer is used, calibrate them against each other.

The next section discusses how to measure dissolved oxygen.

Measuring Temperature | Measuring Dissolved Oxygen | Measuring pH | Measuring Secchi Disk Depth | Measuring Nutrient Concentrations | Measuring TSS | Measuring Chlorophyll a | Measuring Fecal Bacteria

Return to Table of Contents