Water Quality Testing at Lake Chabot with Castro Valley Interns

After spending time first semester learning about watersheds and water quality, Castro Valley interns got out and applied their knowledge in the field at Lake Chabot. Starting along the East Shoreline trail, we walked for 2 miles until we found a dock with easy water access. This was the first time a few of the interns had visited Lake Chabot and they were excited get outside and experience nature so accessible from their home, as well as to learn more about the health of the water body in their community.

Interns mix chemicals with the water sample to test for dissolved oxygen at Lake Chabot

Interns started their water quality testing with dissolved oxygen, knowing that it is essential for aquatic life to survive and is a good indicator of the overall health of the lake. One intern was assigned to collect the water sample, another to read the instruction steps and record the data, and two interns to titrate and mix the chemicals with the sample. During our first test, however, interns observed that the sample was not turning the color it was supposed to and had to review the instruction steps in detail. The group found themselves having the start over a few times, learning along the way and having to reassess their approach to testing and correcting for missteps. While this was a time consuming lesson to learn, it taught interns that often science is trial by error and you won’t get it right on the first try more often than not. Along with having to do multiple tests correcting for errors, interns also conducted multiple tests to make sure their results were consistent.

After testing for dissolved oxygen four times and finally feeling confident in the results, the group decided to hike back and finish up the rest of the water quality testing during our next field visit. Interns recorded dissolved oxygen levels ranging from 7.3-8.2 ppm, indicating that Lake Chabot is a healthy environment for most aquatic life! At our next field excursion, Castro Valley High interns plan to test for pH, nitrates, turbidity, and temperature to continue their investigation into Lake Chabot’s water quality.

Interns assign roles during testing, someone to collect the water sample, another to read the instructions and record data, and two interns to mix the chemicals
Interns repeat the dissolved oxygen test 4 times in total to make sure the results are consistent

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