Hydrology Field Methods

Basic Water Quality Field Monitoring

  1. Calibration

    1. Sensors are not to be trusted! It is difficult to even measure temperature accurately. Try reading the temperature of a few thermometers and try to compare the various measurements. Should you take an average? If there is a measurement bias (the meters read too high or too low), then the average won't do much good.

    2. Does the measurement make sense? Compare the reading to what you think it should be. Try calibrating your sensors. What should you calibrate to? Ice? Boiling Water? The boiling point of water changes with air pressure, and therefore elevation! A more accurate thermometer?

    3. Try using more than one instrument to take a measurement. How do the various instruments compare?

    4. You will be graded on how well you can calibrate an instrument. What standards did you use. How did the numbers compare between instruments.

  2. Documentation (Field notebooks)

    1. We all think we have a perfect memory and will remember everything. Try remembering what you ate on December 3, 1999. How about December 3, 1989? You should write everything down!

    2. Get a lab notebook immediately. Write down who was there, where you were, how you did it, why you did it, what you saw and measured, and when it happened.

    3. You will be graded on how well you document everything. Make sure you have all the important measurements on paper!

  3. Field Equipment:

    1. Many vendors now sell field water quality tools, including kits and multiprobes. Take several of these out to a field site on campus and compare how the various pieces work. Do the numbers look reasonable? Can you trust them?

    2. Try to rank various sites, upstream vs. downstream. Stream A vs. Stream B. Is it so important now to have exact measurements? What if the meter is off by one unit, so instead of reading 24 and 40 at the two sites it reads 25 and 41. Can you still make the same statement of relative conditions?

    3. You will be graded on how well you can eliminate errors from your measurements by proper sampling.