Fourth grade students from La Honda Elementary recently took a field trip to study stream and lagoon environments. They visited two very different sites, and observed habitat and performed water quality tests at both locations.
The first site was on La Honda Creek at Playbowl. This is a densely wooded area with meandering creek and good spawning gravels and water quality. The creek had good flow due to ongoing rains, making it a great time to measure turbidity (water clarity), air and water temperature, water depth, conductivity (salinity), and pH.
The students used data sheets to record observations and test results. Observations included weather conditions, flow rate in the creek, woody debris, habitat conditions such as boulders, gravels and fish barriers. No fish were observed, but students were able to see both artificial and natural structures in the stream channel. Natural structures don’t often create barriers to fish passage, but artificial ones can.
Stream monitors from the San Gregorio Environmental Resource Center (SGERC) guided students through the use of basic water sampling equipment. Turbidity, or the cloudiness of the water, was measured by comparing black dots in the bottom of cylindrical tubes of water. One tube holds creek water, the other holds clear water while units of a clay reagent are added until the clarity of the black dots match in both tubes. Meters and probes were used to measure temperature and conductivity. pH was measured with a test kit that adds reagent to the creek water sample, which is then compared to a color wheel to determine pH level.
A short journey to San Gregorio State Beach, and we were able to observe a completely different environment, but one that is crucial to fish survival – the lagoon. Everyone read and discussed the interpretive panel at this location that describes proper lagoon function and the species that depend on it. In addition to learning the role the sandbar plays in the mix of fresh and salt water, we talked about the harm of artificially breaching it, and how that can disrupt an entire fish-rearing season.
Since the weather continued to be cold and rainy, we repaired to the San Gregorio Store to complete our basic water quality tests. We also measured Dissolved Oxygen in the water, a critical parameter for fish survival. After completing measurements and filling out our data sheets, it was time for lunch!
SGERC would like to thank the teachers, parents, students, and principal of La Honda Elementary for their efforts to make this field trip possible. We’d also like to thank Cuesta La Honda Guild and California State Parks for permission to visit these sites, and also George Cattermole and CWC for support and funding. This program was sponsored by SGERC as part of their education programs and continuing efforts to monitor and improve conditions in the San Gregorio Watershed.
(Also published in The La Honda Voice, March 2018.)
Protecting the San Gregorio Watershed.