Kamo Primary School teachers and Drains to Harbour were impressed with Cordell's two-layered trap – one for larger pollutants and a second for finer rubbish and plastic pieces.
"We talked about it at the staff meeting,'' teacher Neil Leathley said.
"For someone to go home and make something like this in his own time without being prompted really shows the impact this programme is having on students."
In the first classroom session of the programme, students learned about the connection between stormwater and the harbour, particularly the fact that everything going down the drain ends up in local streams and the harbour.
Students also mapped the drains in the school and found there were more than 25 on the Kamo school's grounds, Krauss said.
They then visited Otepapa Stream which flows through Hodges Park to see if it was affected by stormwater pollution.
Like real-life scientists, the students measured water quality and assessed the biological indicators, Krauss said.
The word macroinvertebrate – which students might never have heard before but is now very familiar – describes a large variety of creatures that live in freshwater streams and serve as an indicator of water quality.
Although there might be some effects from stormwater, the Kamo students generally concluded the stream in Hodges Park was in pretty good shape for an urban stream.
Students discovered mayflies and caddisfly as well as some freshwater crayfish (kēwai) living in the stream and its banks.
Back at school they decided to act on their new knowledge, Krauss said, and a Drains to Harbour Littatrap, a type of rubbish catcher, was installed in a school drain.
The trap is a bag inserted into the drain to catch sizeable (called gross) pollutants such as plastic and rubbish but without affecting water flows.
The trap at the school will be monitored and emptied by students on a regular basis.
The students also designed posters to raise awareness about plastic pollution and stormwater drains.
The Drains To Harbour programme is run by Whitebait Connection and funded by Whangārei District Council. It was piloted in 2006.