Interns Help Middle School Students Test Garfield Lake

On Wednesday April 11, our DSISD high school interns went to Garfield Lake Park to work with students from STRIVE Prep Westwood Middle School. These students participate in a Community Adventure Program (CAP) class run at their school by Cottonwood Institute, another local nonprofit. Students in this CAP class explore local environmental issues, choose an issue to address as a class, and collaborate with other organizations to design and implement a student-directed Action Project to positively address their issue.

This CAP class is focusing on water quality and health, so our interns helped them conduct six different tests at Garfield Lake to determine its current status. In March, the CAP class visited Lily Lake near Rocky Mountain National Park and conducted these same water tests. Their goal was to compare an alpine lake to a city lake to see how the quality differed and determine how they could help their local environment.

We evaluated Garfield Lake using six different tests. We looked at temperature, pH, dissolved oxygen (DO), turbidity, phosphates, and nitrates. Here is a quick rundown of each test:

Temperature
We took a thermometer and put it in the lake water for approximately 20 seconds. On this day, it read 20° Celsius, which equals 68°F.

pH 
We filled a test tube with 5 mL of lake water. We added an activation tablet and shook the tube until it was dissolved. We compared the color the water turned to a chart that let us know what the pH was. It turned green, which is a pH of 7, or neutral. This is great for aquatic life.

Dissolved Oxygen
We completed a similar test to pH for DO. We took a smaller test tube and filled it with lake water. We added two activation tablets to the water, shook the tube, and waited for them to dissolve. Our result was a pale pink color, which our chart told us was about 4 parts per million (ppm). Since higher temperatures reduce DO levels, this was still a healthy level for critters.

Turbidity
We used a plastic cylinder with a Secchi disk symbol on the bottom to measure the clarity of the lake water. We determined it was around 12 Jackson Turbidity Units (JTUs). While the water was fairly clear, we did find lots of little water bugs swimming around in our sample!

Phosphates
We tested phosphate levels using a similar test to pH and DO. We filled a test tube with lake water, added an activation tablet, and waited five minutes. We determined the concentration was 2 ppm. According to our chart, this was fair, but further research told us that anything above 1 ppm can negatively impact aquatic life.

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Nitrates
We tested nitrate levels with another test tube and tablet combination. The two tablets we added showed a yellowish color, which told us it was about 3.5 ppm. Like the phosphate test, this concentration is fair but not great. Both phosphates and nitrates act as fertilizers and cause rapid growth and decay of aquatic plants.

Overall, we were pleased to find that Garfield Lake is in better shape than the students expected. We enjoyed working with these students and look forward to seeing how these tests will influence their action project and interest in environmental issues going forward.