Testing to Determine Water Quality

Water can be encountered in many different states of quality. Some water could be full of algae, some could be really murky and turbid, and some could be very clear and blue. The look of water can be deceiving, and the clearest waters can also be the most unsafe to drink or live in. Both the qualitative and quantitative qualities of water and its feedback cycles can be transformed into student-driven labs.

• How do we evaluate and make decisions about our water based on its effects on all Earth systems?

• Which water sample is the healthiest? Why do you think so?
• What could it mean for something to be “healthy” or “safe”? What different standards can we come up with?
• What could be influencing the observations you made?
• What do you notice about these water samples? What do you wonder?
• How can we test our ideas and questions?  
• What health levels are best to be the easiest to maintain? What health levels would be best to support our health? What health levels would be best to support the health of other organisms and systems in an ecosystem?

Students could: 

• Tie this study to a storyline about watersheds and the Mississippi watershed and implications for our area or areas further down the watershed. Example: How do the chemicals and nutrients in our water systems influence areas downstream? How can they change how the water is cleaned or used?
• Perform a biological assessment of benthic macroinvertebrates in the area in order to determine what species are able to live in this water. What species are missing? Is the water quality for species to live different from the water quality we need for our many uses of water?
• Perform physical and chemical assessments of the water and the surrounding habitat to look for red flags caused by human impacts or ecosystems out of alignment.  (PDFs included)
• For students who need an extra challenge or more STEM tie-in, they can also graph data over a couple of weeks or over a semester to analyze changing conditions, or they can try to design filtration devices to target a specific nutrient or chemical in the water nearby.  (P.E: Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity. HS-LS2-7 )
• For a shorter activity, students could bring in water sources from their houses or try different bottled water brands.  They could do taste tests and then measure the different dissolved mineral levels in the water.  Is there a correlation?  This could be embedded in a unit or serve as a stand-alone activity to practice observation, experimental, and data recording skills.
• Take pictures of bodies of water near their homes and compare the qualitative vs quantitative data.  They can determine whether the water looks “healthy or unhealthy” and come up with an operative definition for these words.

• Kent Lake Water Quality Test Results Averages: 2022 Water Quality Data Set for F.W. Kent Park in Johnson County (various tests and results included from April-July).
• Iowa Department of Natural Resources (DNR) | Habitat Assessment: This assessment can help to evaluate the habitat quality of waterways anywhere.
• Iowa Department of Natural Resources (DNR) | Water Chemical and Physical Assessment: This assessment can help to evaluate the chemical and physical condition of waterways anywhere.
• Iowa Department of Natural Resources (DNR) | Biological Monitoring and Assessment Database: Bionet is public information about the water quality and biotic life found in nearly all of Iowa’s waterways.
• Izaak Walton League of America | Biological Monitoring Data Form for Stream Monitors: Izaak Walton League’s Biological Monitoring Data Form for Stream Monitors allows students to calculate the biotic index of a stream. Educators can focus on the Macroinvertebrate Count and Water Quality Rating sections. If looking for extensions the rest of the form is useful for making observations about the sampling location and surrounding area.