Today, the normal groups that we had been working in for the past week got split up and put into new groups. Ivy and Kayden went to go work on seismology with Kate, where they looked at data from different seismometers that they had set out earlier. Hailee and Dana went to go work on photogrammetry with Michelle. I, Melody, went to go look at sedimentary deposits at Coldwater Lake with Kate and Cynthia. First, we got out some of the water quality probes that they had brought with them and worked on learning how to use them. Kate and Cynthia had set out two beakers full of water, and each group member was able to put their probes in the water and measure and record the pH, conductivity, and temperature of the water. After everybody had taken their measurements, Kate and Cynthia added 10 mL of conductivity standard KCl solution to the water. Again, we took and recorded measurements with the probes. We repeated this once more, adding 20mL more of KCl solution to each beaker. Each person shared what they had recorded, and we observed the differences in measurement between each probe. Even though they were all the same brand and model of probe, each had significantly different measurements of the same solution. This exercise taught us how to use these water quality probes, as well as teach us the importance of being consistent in which probe you use when taking actual measurements.

After we had done this, we got in the cars and went down to Coldwater Lake. We went down Birth of a Lake trail, during which Kate and Cynthia (as well as the interpretive signs) gave us the history of how the lake formed. Before the eruption, Coldwater Lake did not exist. Instead, there was just Coldwater Creek. However, after the eruption, the debris landslide blocked off this previously small creek and acted like a dam. Over time, the creek water (and rain water) accumulated to form the lake that exists today. After going along the boardwalk and looking at the lake and noticing the details that pointed to its formation, we went down to the shore with some of Kate’s equipment for analyzing sediment size and distribution. Once we had gotten there, we took some sediment samples (shovels full of dirt from the shore) and put them through layers of sieves to separate them into different groups of particle size. We then weighed the total sediment that had gone through the sieves as well as each individual group of sizes. From this, we made an approximate size distribution map of the sediment along the shore. Even though it was hardly accurate, it was a good experience to learn more about how scientists conduct experiments to learn more about the past and current states of streams and bodies of water.

Contributed by the Lava Roses

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