Rere School students learn to keep waterways pest-free
Rere School students became citizen scientists for a day as they navigated lessons on water pests and water testing.
“We are combining our local curriculum with the national curriculum — particularly around science,” principal David Milne said.
By incorporating outdoor activities, the tamariki not only learn different skills, but gain an understanding of the ecosystem.
The school chose the Wharekōpae River as part of their learning ground and were joined on their field day by representatives from Toi Ohomai Institute of Technology and Tairāwhiti House of Science.
The day began with a karakia followed by a presentation about water pests by Toi Ohomai environmental management student Emily Fitzgerald.
“I'm here to tell the kids about how to prevent the spread of freshwater pests using the Check, Clean and Dry strategy,” she said.
This method involves removing plant matter from gear and leaving it at the site, thoroughly cleaning the gear with a mix of dishwashing detergent and water, then ensuring gear is completely dry to the touch.
Invasive freshwater pests can squeeze the life out of New Zealand's most precious rivers and lakes. They can be spread by a single drop of water or plant fragment or single fish egg, which is why the check, clean, dry strategy is so important.
Pest plants and pond weeds like hornwort can grow up to 10 metres tall and can be dense and thick. As a result, a lot of native plants in the river are deprived of the sunlight they need to grow.
“These pest plants can sometimes float in a big mass and rot, which is bad for water quality,” Ms Fitzgerald said.
Along with pest plants, fish such as koi carp are another concern. These large goldfish, which measure 75cm long and weigh almost 10kg, are voracious eaters.
“They suck up everything from the bottom and spit out the stuff they don't want, things like sediment and dirt. This makes the clarity of the water really bad. Subsequently the ecosystem gets destroyed as it is pretty much a monoculture,” Ms Fitzgerald said.
Although koi carp and catfish are present in the Bay of Plenty and Hawke's Bay, not following preventive measures could discharge the species in Tairāwhiti.
While plants and fish are visible pests, invisible pests like didymo also need to be monitored.
“That is where the check, clean and dry strategy comes in. It was created to slow the spread of didymo when it was found in the South Island in 2004,” she said.
Fragments released by freshwater pests stick to a person's gear, clothes and boat.
“If unchecked or uncleaned a person can take those pests to another water source and result in its declining health,” Ms Fitzgerald said.
The tamariki then answered a series of Q&A's on the pest briefing and joined House of Science Tairāwhiti manager Mihi Hannah for water testing.
“One of our many science kits is called Water Analysis. This kit enables ākonga (students) to study the water quality of an awa that is precious to them,” she said.
Ms Hannah said any teacher could pick up the kit along with the manual and utilise the equipment.
“Not only are they learning valuable citizen science skills, but they are reading instructions, writing their observations and collecting data. The New Zealand curriculum is embedded in their learning. As a scientist they are gathering and interpreting data through observations of the stream bed and the surrounding land, using all of their senses to interpret what they notice and gathering quantifiable data to critique the evidence they have collected,” she said.
The students tested the water quality of the river using six parameters — temperature, clarity, velocity, stream bugs, nitrogen content and pH.
The students were divided into groups to check for different parameters.
Some of them tested the clarity of the water using a clarity tube, while others measured the velocity of the waterway.
“The clarity tube is used to work out how clear the water is using a visual measurement scale, whereas the velocity is measured using a rubber duck, stopwatch and measuring tape,” Ms Hannah said.
It is crucial to monitor and collect data regularly to help make decisions about what is being observed over time. This is when you can interpret what the science means.
Ms Hannah also introduced the students to a piece of equipment called the “bug sucker”.
After collecting bugs from the stream, the tool is used to suck up the macroinvertebrates to classify them by putting them into separate sections of their collection container. Then they can count and identify their macroinvertebrates, ” she said.
Invertebrates identified as green mean that the water is rated “good”, but a red rating means “bad”.
“Having found mainly green macroinvertebrates gives strong evidence that the stream is in good health.”
Even though the students concentrated on one part of the river, it was part of a bigger picture.
“The water collected by the catchment is pristine and it is the job of each and every person in contact with that waterway to ensure that the quality remains that way from the awa to the sea.”
The day ended with the tamariki taking the water analysis data back to school to discuss and analyse. Ms Hannah said the overall test results were “excellent”.
“It is important to take care of the awa and keep it in the best condition possible so that they can pass over the mantle to the next generation.”