Site 1: Canyon Picnic Area in Saratoga, CA

Site 2: Stevens Creek Reservoir

Site 3: McClellan Ranch in Cupertino, CA

May 26, 2023

We visited Site 1 and Site 2 in the morning, 10:00 am to 12:45 pm.

We visited Site 3 after lunch, from 1:30 pm to 3:00 pm.

It was a warm and sunny day with a high of 68° F.

Our focus on this excursion was to observe the way water and its inhabitants changed as we traveled down a watershed. We started higher in the watershed, surrounded by mountains and a clear flowing creek. We took both biotic and abiotic measurements to examine the health of the creek and determine if impacts of pollution were present. Then, we visited the reservoir to observe the interruption and containment of the system. For this reservoir, the water flows from the bottom of the dam rather than over it. This means that the water that flows into the creek below the reservoir is very cold and carries sedimentation. The water had a blue-green color. Our final investigation of the water quality was at McClellan Ranch in Cupertino. Once again, we took biotic and abiotic measurements to assess the condition of the creek system.

There were a variety of abiotic measurements that differed between the two Stevens Creek sites. The first site was located at a section of Stevens Creek that was higher in the watershed, in the mountains, and before the water gathered at the reservoir. The second Stevens Creek site was below the reservoir, at McClellan Ranch, and surrounded by urban development. The first site had a more basic pH, slightly above 8, in comparison to the second site, with a pH slightly above 7. Because organism systems are so sensitive to pH in their ability to function, I remember being surprised that the less healthy system was closer to a neutral pH than the more thriving system. The water temperature was colder at the site higher in the watershed. Turbidity in a system measures the degree of light scattering by particulates in the water. This shows up visually as the water looking more cloudy or full of silt. The first site had a turbidity measurement of 28 while the second site had a turbidity measurement of 68. The measured data reflected my own observations. The water went from looking incredibly clear and clean to looking like a cloudy blue with an overgrowth of algae downstream. Another noticeable difference was the moderate flow of the creek higher in the watershed through areas of pools and ripples. The ripples provide valuable habitat for the macroinvertebrates.

A second set of measurements at the two sites included macroinvertebrate sampling. Another way to measure the health of a creek ecosystem is to observe if macroinvertebrates that are sensitive to pollution are present. At the first Stevens Creek site, we found many sensitive organisms such as five water pennies, ten stoneflies, fifteen mayflies, and ten caddisflies. We also observed pollution tolerant species such as an aquatic worm, five blackflies, and around ten introduced and invasive water snails. At the McClellan Ranch site downstream, the only pollution sensitive macroinvertebrates that we found were three mayflies. We saw the stream overrun with the invasive snails. We also saw pollution tolerant blackflies and an aquatic worm. There was a stark contrast in which macroinvertebrates were present, coupled with a stark contrast in the levels of joy the students of the class expressed in exploring each site. Upstream, there was a vibrant and dynamic feeling of curiosity, of joy in wading through the water and exploring under rocks. Downstream, the water looked contaminated, and it was not joyful to touch it or find hordes of snails. Luckily, the restoration efforts after exploring the second creek site brought us to beautiful landscapes. Even more, it reminded us that we can turn things around when we engage with the problem and work together.

During our stop at the reservoir, we came upon a spring that created a puddle along the trail. In the spring we observed tadpoles, green algae, and ostracods. The ostracods and tadpoles were very interested in some type of detritus. In the photos, the ostracods are the small, round, orange organisms. They are crustaceans and sometimes called seed shrimp.

Two other exciting moments of the day were snake encounters. The king snake is a black and white snake that eats other snakes, including rattlesnakes. The one we observed was by the trail, quite mature, and able to slide away quickly. While we took a look, it shook its tail like a rattlesnake! I can confidently say that we were not fooled but wonder if it came in handy for it on another occasion. The second snake we saw was a ring-necked snake. The top of the snake is a tan color with an orange ring at the neck and an orange belly. We were walking along the trail at McClellan Ranch and a fellow student looked down. They thought to themselves, why is that worm moving like that? And then the realization set in that it was a snake! It was a lucky day for the snake because it was saved from an entire class about to walk right where it was resting. The two snakes had stark differences in size and color, but both brought me an inordinate amount of joy.