Karori School children concerned about what's going into their stream

Students at Karori West Normal School are distressed about the pollutants which are being released into the stream which runs alongside their school after authorities investigated five pollution incidents in one day.

On the morning 17 April Greater Wellington Regional Council and City Care staff were investigating a report of oil or fuel in the Karori stream near the Karori West Normal School. While trying to trace the source of the spill they discovered discolouration of the stream in two more areas and later found bubbles flowing down a section of the stormwater network. Later that afternoon the regional council’s Pollution Hotline received more notifications about sediment-laden water coming into the stream.

"Our students often delight in watching the eels meandering in the stream - you can see them clearly from our bottom field. They will be horrified at the thought that these eels, and other stream life, might be hurt by the thoughtless release of dangerous substances into our waterway," says Deputy Principal, Karori West Normal School, Janice Jones.

"On this particular morning fumes coming from the stream were so strong we could smell them in the staff room. These are such special creatures and they are already under threat. They travel all the way to Tonga to spawn and then die and the elvers migrate all the way back and up our rivers and streams. We were worried they might have been affected by the discharges as we had not seen them for some time, but they were recently tempted out from hiding with the offer of a little food."

Two species of eel occur in the Karori Stream, the shortfin eel and longfin eel. The longfin eel is the largest freshwater eel in the world and can grow up to 2 m long. It can be extremely long-lived (up to 100 years old) and is an endemic species which means it is found nowhere else in the world. The longfin eel is classified by DOC as declining throughout NZ.

"Both species of eel are important parts of stream ecosystems. They eat the insect larvae, water snails and worms that live in the stream and as they get bigger they also eat other fish. A range of other fish species occurs in the Karori Stream including the adults of 'whitebait' such as koaro and banded kokopu. Even very small amounts of oil, detergents, chemicals or sediments in the water smother and kill their food source, alter their habitat and can affect and poison eels and other fish," says Juliet Milne, Aquatic Ecosystems & Quality, Team Leader at Greater Wellington Regional Council.

"We can't stress enough how important it is to let nothing but pure clean water go down the storm water drains. Stormwater drains directly into our water ways and ultimately into the sea without being treated. It may only take a small amount of chemical contamination to tip the delicate balance of an aquatic ecosystem," says Greater Wellington Regional Council, Environmental Protection Officer, Naomi Middleton.

"People can help by calling the environmental hotline as soon as possible if they suspect a pollution incident. We are more likely to find the source of contamination if we can investigate quickly."

Greater Wellington Regional Council's 24-hour Environmental Protection Hotline free phone number is 0800 496 734.