Planning Guide for Water Monitoring
Water monitoring takes place rain or shine, but we don’t go out if the site conditions are unsafe due to heavy rain, thunderstorms, snow/ice, or other hazardous conditions, and usually not when the temperature is below freezing. Consult the Program Calendar to see what dates are currently available. Before you go: It is helpful to allow students to practice at least one chemical test prior to water monitoring, and also to give them an overview of what they will be doing in the field. It is ideal when students arrive with even a small bit of their own “expert” knowledge, whether it is how to perform one chemical test, familiarity with a single species of benthic macroinvertebrate, or even a vocabulary term (riparian or erosion, for instance). It is also best to assign groups for rotations and pairs or teams for doing chemical tests, if desired, prior to arriving at the monitoring site. What to bring:
Earth Force brings all necessary waste containers, rinse bottles, nets, waders, test kit (if not provided to teacher), folding tables, field scopes, magnifiers, etc. Activity stations, rotations, and time on-site: In order to keep group sizes manageable and to allow for hands-on experience, we have groups of students rotate through several stations examining different aspects of water quality. Ordinarily, these are the physical, chemical, and biological assessment stations. From experience, it is ideal to plan for about 35-40 minutes at each station (definitely no less than 20 minutes, which is extremely rushed); longer than 40 minutes usually isn’t any more productive. Allowing for a little time between rotations, as well as some time at the beginning for orientation and at the end for sharing results and reflecting, ideally you should plan to spend at least 2.5 hours on-site, if possible. Lunch on-site adds time, as does transportation to and from school. The physical assessment is typically conducted while walking along the stream and observing the setting, and it provides a broad context for understanding water quality. Students consider the nearby conditions, including land use, vegetation, aquatic habitat, and erosion, and they make observations about the water itself—whether it is muddy, foamy, smelly, etc. When time allows, they might also determine the discharge by measuring the flow velocity and cross-sectional area of the stream. Physical survey data sheets are found in the Field Manual on pages 132-135 (also below). The chemical assessment looks at what is in the water, and results can very much depend on recent weather conditions or specific events. It is thus a “snapshot” of water quality at the time of the field study. Students use non-toxic chemical tests to determine nitrates, phosphates, dissolved oxygen, pH, turbidity, temperature change over a short distance, as well as whether fecal coliform bacteria are present. Some groups collect samples to be analyzed in the lab for colony counts of E. coli, which can be compared to state water quality standards. Results can be used to calculate a Water Quality Index using the data sheet in the Field Manual on page 136 (also below). The biological assessment determines what aquatic organisms are present in the stream; based on the diversity, abundance, and pollution tolerance of the species found, results give a longer-term picture of water quality, since aquatic organisms live in the water year-round. Students in waders use nets to capture benthic macroinvertebrates (Macroinvertebrate Web Links), then identify and catalog the species found. Results can be used to calculate a Pollution Tolerance Index using the data sheet in the Field Manual on page 137 (also below). When time and supervision allow, other stations and activities are often included to engage a broader set of skills (sketching, writing, or photography stations, for example) or to accommodate larger groups. The possibilities are endless, and we encourage you to be creative! |
