|The Tennessee Conservationist Home
Great Hikes with Fran Wallas
Magazine Index - 2003 to current
2008 National Trails Award
This student measures dissolved oxygen in a water sample for the World Water Monitoring Challenge. Photo by Norman DeWein.
By Michelle Rogers
On a warm, sunny morning in May, 80 third graders from Clarksville’s Norman Smith Elementary unload from school buses at their field trip destination.
They carry sack lunches and backpacks with an extra pair of shoes for each child. One teacher explains, “The bus drivers won’t let them back on the buses with wet shoes.” With the temperature approaching 80 degrees and no chance of rain, they’re sure to need those spare shoes. The students are here for a taste of nature. Sure, it’s a county park with a playground and bathrooms around the corner, but the hiking trail leads into the woods and Wall Branch Creek winds its way through the park, carrying water to the Cumberland River.
One of the special experiences these third graders will have today is an opportunity to wade in and explore this shallow creek that is home to small fish, salamanders, turtles, water snakes, and countless invertebrates like snails and damselfly larvae. Though the creek is small enough to cross with one giant step in some places, birds and other wildlife in the park rely on it as water source. For these third graders, it is an ecosystem on a very personal scale. They can touch it, smell it, and really get to know it. Adult volunteers will introduce students to the idea of caring for our aquatic habitats. They will help the students take water samples from the creek and perform tests to check the quality of the water and explain to them why clean water is important to all life.
These elementary students are part of a much larger project called the World Water Monitoring Challenge. Last year, over 300,000 people, across 77 countries around the world, participated. Groups, like these students, collect basic water quality data on a nearby water body, and then enter their data in the WWMC Web site www.worldwatermonitoringday.org. Data entered is available to all users, in real time, through the online database or as a downloadable spreadsheet. At the end of each calendar year, all collected data is compiled to create the polished, professionally-designed “Year in Review” report. Students can compare their water quality data to national and international averages. They can see how their contribution becomes a part of something bigger.
Anyone can participate in WWMC, though most often participants are students in grades three-12, in schools, scout groups or clubs. WWMC tests are very simple and no expert help is needed, but sometimes, student groups partner with city and county water quality staff, parks departments, watershed protection groups, private industry and others with an interest in water quality. Younger children do need adult supervision in or near water and while conducting the chemical tests. The Norman Smith students were assisted by staff and volunteers from Project WET Tennessee (Water Education for Teachers) including students from Austin Peay State University.
Simple water monitoring test kits are available for purchase on the World Water Monitoring Challenge Web site or through a variety of other online suppliers, including LaMotte, Carolina Biological, and Fisher Scientific. To gather all the data requested by WWMC you will need to measure temperature, turbidity, pH, and dissolved oxygen.
All aquatic animals have a range of temperature that is required for their survival. Water temperatures above or below that range can stress the animal and reduce its chance of survival. Warm water is especially hazardous to many animals because warm water is less able to hold dissolved oxygen that aquatic animals require. Warm water discharge from industry and energy generation can reduce water quality simply by raising its temperature. Preserving trees in the riparian (stream-side) areas that shade creeks and rivers can keep water cool and help maintain healthy water temperature.
To measure stream temperature, of course, you will need a thermometer. Choose one that will not break and NEVER take a mercury thermometer into a stream. You can buy a glass thermometer enclosed in a plastic protective sleeve, or better yet, choose a digital, liquid crystal display, stick-on thermometer like those used in an aquarium. These are safe and easy for even young children. Depending on the water body you monitor, you may need one or more thermometers to cover measurements from 2° C to 30° C (36° F to 86° F) at intervals of no more than 2° C.
Q: What’s the number one pollutant of Tennessee rivers?
A: Sediment, soil, silt, DIRT.
It may surprise you to know that the most common and damaging pollutants in Tennessee rivers is dirt. Sediment that runs off construction areas, agricultural fields, and eroded stream banks diminishes water quality. Silt can interfere with animal respiration, smother fish eggs and reduce aquatic plant photosynthesis. It’s crucial to keep soil in its place. There are techniques for farming and construction to help, such as silt fences and contour plowing. Perhaps more importantly, we can maintain thick, natural vegetation along stream banks to slow runoff, filter out silt and stabilize stream banks.
Measuring turbidity tells us how much light passes through water. A low turbidity measurement means clear water. A high turbidity measurement means water is contaminated with sediment, algae overgrowth, or another substance that reduces water transparency.
All aquatic animals need oxygen and they get it from oxygen dissolved in the water. Water that is too warm, because of heated inflow or lack of riparian shade, can have low dissolved oxygen (DO) levels. Another common cause of low DO is excessive organic matter in water. This can result from fertilizer runoff, sewage, or animal waste. Bacteria feed on organic matter, consuming oxygen in the process, reducing the DO available for fish and other animals.
Simply described, pH is a measurement of how acidic, or basic, water is. Most aquatic animals tolerate a narrow range between pH 6 to 8. Values below that range are too acidic; values above are too basic. When precipitation picks up air pollutants from the burning of fossil fuels, the result can be acid rain that flows to streams. Surface runoff from mining coal can also affect water’s pH.
When the third graders tested the water at Rotary Park on May 2, they got a snapshot of the water at a particular moment in time. But they can’t be there to check the water every day for a week or a month. Is there something more they can do to investigate the health of this ecosystem over a longer period of time, and complete it in a single day? Yes. It’s called biological assessment or bioassessment. By examining the organisms that are living in a body of water, and considering how tolerant those organisms are of poor water quality, we can draw some conclusions about how clean the water has been over much longer periods.
Stream bioassessment is most often done with benthic (living on the stream bottom) macroinvertebrates (organisms without a backbone), mostly aquatic insect larvae (like dragonflies), snails, and worms. These animals tend to live in one place for weeks or months and vary in their tolerance to poor water quality. For example, if a stream has mayfly and stonefly nymphs, that are both sensitive to pollution and are only able to survive in clean water, we know that the water has been clean throughout their lifetimes of several months. If a stream has only leeches, aquatic worms, and midge larvae, which are very tolerant to pollution and poor water quality, we can deduce that it has had water quality problems, no matter how clean the water may seem on a given day.
In the creek at Rotary Park, the third graders found a lot of caddisfly larvae that build tiny homes for themselves out of stones. After turning over rocks and seeing just how many tiny animals lived there, one small girl remarked, “Now, I’ll have to be careful where I walk. There are things alive everywhere!”
There are a variety of bioassessment protocols in use by different groups, but the one used by WWMC is a simple list of representative groups. Participants record the presence or absence of each type of organism.
WWMC is intended primarily for education and outreach, but it can easily be the gateway to more serious water science. Across the country, there are many volunteer water monitoring projects. Ongoing, long-term monitoring allows volunteers to obtain baseline test values and learn what is “normal” and how values fluctuate. Volunteers can then identify threats and sound the alarm when unexpected changes of water quality occur in the water body they monitor.
If you would like to learn more about World Water Monitoring Challenge, please visit the Web site at www.worldwatermonitoringday.org. Every year, an official World Water Monitoring Day takes place September 18, but the “challenge” program runs from March 22 to December 31. Talk to a teacher you know about how you might help their class participate. Ask a scout leader if their troop would like to join you. Get involved!
(Michelle Rogers is a biology instructor in The Center of Excellence for Field Biology at Austin Peay State University in Clarksville. She also serves as the Tennessee State Coordinator of Project WET (Water Education for Teachers), working with K-12 teachers and students to increase awareness of water quality issues.)