Catlin Gabel 7th Graders’ State of the Creek Report – 2018

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2018 Annual State of The Creek Report    –  Catlin Gabel 7th Grade Class

Golden maple leaves wash downstream as Coho salmon climb against the current on their return to Lousignont Creek. One season ends and another begins. For the seventh-graders at Catlin Gabel School, this marks the end of another rewarding field season at Hyla Woods. Each year for the past six years a new cohort of student-scientists have ventured into the forest braving the elements, learning the skills of field ecologists, and taking the vitals of the creek in advance of the returning salmon. Every year brings with it new lesson and new stories, both poetic and analytical…often both. Each student tells the story of our work while writing their own State of the Creek Report. Students write, peer-review, edit, nominate, vote…and ultimately select a single report to share on the Hyla Woods website. At least, this is how it usually works. This year TWO student reports were equally supported by the class, and we’ve decided to share them both! Huge congratulations goes out to Caden and to Eva on their State of the Creek Reports. Thank you for representing our class. You make us proud!

 Jesse Lowes    –  7th Grade Science Teacher

 Eva’s State of the Creek Report (see below)

 Caden’s State of the Creek Report: Caden’s report includes a collection of powerful interactive graphics best viewed online. Please follow this link to read his report:

Want to read more State of the Creek Reports by Catlin Gabel students? Follow this link for a selection of finalist reports (as nominated by their peers):

Want to give our data a closer look? Check out our online water quality database reporting on the research carried out by Catlin Gabel seventh-graders going back six years:


 2018 Hyla Woods State of the Creek Report

By Eva


If you are quiet enough

you can hear the song of the woods

You must wait

until the pattering of rain
with the warning calls
of a crow
flitting through the branches

You can spot the tangled webs
of lichen
stretched between the streaks of brown
splattered with green
that make up the trees

You must wait
until a single ray of sunshine
pierces the gathering mist
and is captured
in a single drop
from the dripping tightrope
of moss

And only then
and only then
will you realize that
that was
the song of the woods


Our woods contain many diverse ecosystems. From the songs of birds to the flitting tails of fish, these ecosystems are essential to our survival. An ecosystem is an elaborate web of abiotic and biotic components, all depending on and working together with each other to ensure their survival. But what makes an ecosystem healthy? How can we tell? The 7th graders of Catlin Gabel visited Hyla Woods twice on science field trips to explore and investigate these questions. Hyla Woods, owned by Peter and Pam Hayes, has a goal of being a profitable logging service while also maintaining a healthy and diverse ecosystem. During the salmon runs, the endangered Coho salmon lay their eggs in places like Lousignont Creek, the creek in Hyla Woods. We ran tests on the water of Lousignont Creek to inform Peter and Pam if the creek and salmon are healthy or not.


Each of the four 7th grade science classes were split into three groups, making 12 groups in total, and were assigned a site along the creek. Working with our teammates, we tested the water. Our tests included water and air temperature, pH, dissolved oxygen, and turbidity. We also collected data about the creeks tiny inhabitants. The macroinvertebrates, such as mayflies, stoneflies, snails, aquatic worms, and many more, are bioindicators, which means they can tell us if the ecosystem is healthy. We wrapped up our first trip to Hyla Woods getting to spend time in and around Peter and Pam’s cabin, eating lunch and writing poetry about the forest around us.

When we first got off the bus, we were led down a steep hill to the cabin. We took a few minutes to look around us and breathe in the fresh, pine scented air, before trekking down to our sites. My group, group E, started to unpack and start our tests. While some team members tested water and air temperature, others filled up the turbidity tube and put on their safety goggles to start testing pH.

Water temperature is very important in an ecosystem. Higher water temperatures can be caused by conditions like direct sunlight, higher air temperature, cloudy water, and more. To get the water temperature, we held the thermometer in the water for 2 minutes. The Coho salmon thrive well in the optimal range of 5-15 degrees Celsius. The class average for this year in water temperature was about 11.5 degrees Celsius, which means that the water temperature is sufficient for the survival of coho salmon.

Turbidity was also tested. Turbidity is the cloudiness of the water. Water that is highly turbid has many negative effects. Sunlight can’t reach the aquatic plants, which are crucial parts of many ecosystems. This can go the other way, too. Since the suspended solids in the water absorb sunlight and heat, algae blooms are more prone to occur. The coho salmon’s eggs can be buried in the sediment, which will cause a decrease in their already threatened population. In addition, all the sediment floating in the water can get caught in the fish’s gills. All these problems can be traced back to soil erosion, pollution, floods, and more. To test turbidity, we used a turbidity tube. A turbidity tube is a long tube that has a black and white checkered pattern on the bottom. We poured water into the tube and looked to see if we could see the checkered pattern. Luckily, we could! This meant that the water was very clear, and not very turbid. Along the tube are measurement markings in centimeters. If we weren’t able to see the bottom, then we would have had to empty some of the water, lowering the number of centimeters. We then used a conversion sheet to convert our centimeters to NTU (Neophelometric Turbidity Units), which measures the turbidity of the water. The lower the NTU value, the less turbid the water. Coho salmon are negatively affected ranging from 25 NTU to 70 NTU, depending on how long they are exposed to those turbidity levels. Our class average was <10 NTU, desirable for thriving salmon.


Dissolved oxygen was one of the most complicated tests. Dissolved oxygen is the oxygen in the water, measured in parts per million (ppm). Living organisms need oxygen to break down food and maintain and build cells. High turbidity, along with warm temperatures, high altitude, and slow flowing water, can all cause lower amounts of dissolved oxygen. The opposites, low turbidity, cold temperatures, low altitude, fast moving water, and aquatic plants can all cause higher amounts of dissolved oxygen. To test dissolved oxygen, we used safety goggles and a few concoctions of chemicals. The minimum range for dissolved oxygen is 8-12 ppm, and our class average was about 8.8 ppm, a little low, but still in the optimal range.

pH was one of our last tests. It measures how acidic or basic the water is. The lower the pH, the more acidic the water. Lower pH can be caused by acids released from dead plants or animals, whereas higher pH can be caused by calcium. Salmon need a pH of 6.5-8.25, which is around the middle of the pH scale, between basic and acidic. This test, like dissolved oxygen, required safety goggles and chemicals. Our class average was about 6.43, just out of the optimal range, but not enough to worry about.

One of the most important analyses in our ecosystem investigation was our leaf pack. The leaf pack was constructed by collecting the scattered maple and alder leaves around us and placing them into a mesh bag. Our group then placed it under a sheltered log, in the water. We marked it with surveyor’s tape and packed up our tools. In a few weeks, we would come back to our site and investigate what macroinvertebrates had made a home in our leaf pack. These critters would play a pivotal role in determining the health of the ecosystem.

On our second trip to Hyla Woods, a few weeks later, we did the same tests. This time, though, we collected our leaf packs and sorted out the macroinvertebrates. At our sorting stations, we classified the macroinvertebrates we found. The invertebrates were also listed in three different categories; tolerant, somewhat tolerant, and sensitive. These ratings classify the invertebrates by their tolerability to accommodate in compromised water quality. Tolerant invertebrates would be more likely to survive than sensitive invertebrates in polluted water. If we encountered many macroinvertebrates listed as sensitive, then we would know the creek was healthy. Some of the macroinvertebrates we found were mayflies, stoneflies, damselflies, snails, aquatic worms, and more. We then calculated the biotic index, which is the average taxon tolerance value of the invertebrates we found. Our class average for biotic index was about 3.9, which is judged as good stream quality. We also found the EPT score. The EPT score is the total number of mayflies (Ephemeroptera), caddisflies (Plecoptera), and stoneflies (Trichoptera), which are all regarded as sensitive, added together and multiplied by 100, then divided by the total number of all invertebrates in the leaf pack. It is basically calculating whether or not there are enough sensitive invertebrates in the creek. If there are a lot, our EPT score will be higher, and the creek will be healthier. Our class average EPT score was about 66.99, which is exceptional because anything greater than 27 is excellent.

Our trips to Hyla Woods investigated the question, How can we tell if an ecosystem is healthy? Our test results will reveal the answer to this question. In general, Lousignont Creek is healthy. Our experiments showed that the water temperature, turbidity, dissolved oxygen, pH, and leaf pack results are all well in or just out of the optimal range for coho salmon. Compared to previous years, the creek is still healthy, but perhaps declining the slightest bit. We can’t be sure, though, until we have many more years of data. Temperatures have risen, and the amount of dissolved oxygen has gone down, but these things do fluctuate. From the perspective of this year’s 7th graders at the Catlin Gabel School, Peter and Pam Hayes have reached their goal of running a profitable logging service while also maintaining a diverse and healthy ecosystem. Thank you, Peter and Pam, for letting us visit your forest!