Scott Farnum looks for insects collected earlier and counts them and attempts to classify the species.
Photo by Andy Towle.
Recently Payson High School ecology and biology students packed onto a school bus and traveled to different points along the Verde River to measure pH levels of water, velocity and depth, and to look for organisms. The preponderance of delicate organisms can mean water has stayed healthy a long time, according to biology teacher Joe Schmidt.
Half the students crowded by the river measuring pH levels — acid — and determining the chemical content of water by using spectrophotometers. The machine shoots light through vials of water, and students determine chemical composition based on transparency. Chemicals the students have found include phosphate, nitrate and the aforementioned dissolved oxygen.
Slightly down river, students wearing waders stepped gingerly into the water with measuring sticks and string to determine depth and width. They also sought out signs of life.
By inventorying various invertebrates such as the stonefly larvae that students found, they can determine the water’s health.
Stonefly, for instance, need rather clean water. Chemicals offer a snapshot of stream health, while the organisms found offer a longer timeline. The presence of delicate organisms means that high water quality has been relatively consistent over a longer period.
As students measure spots farther upstream, the water becomes cleaner because it’s closer to the spring, Schmidt added.
In the past, contingents of varying students take these trips six times each year. In addition to ecology and biology students, physics and life science kids have participated.
Arizona Public Service and Salt River Project have provided funding in the past.