Pollution entering the Maitai River from the Trafalgar Bridge stormwater outlet
Clean Swimming Holes
Maitai/Mahitahi E. coli Source Identification
We've been monitoring E.coli levels weekly in dry weather at low tide at four locations around the Collingwood St Bridge swimming hole since May 2015. We know there are often elevated E.coli levels in rivers and the sea after rain because of surface water run-off and leakage between the stormwater and wastewater systems. So we wanted to see if there is elevated E.coli in the river during dry weather and when there is no tidal influence. The results show generally low levels at the swimming hole which is great news. We also sampled the same locations at mid-tide for 6 weeks and found there were no tide-related increases in E.coli.
It's too soon to say it's consistently safe to swim in the Collingwood St swimming hole in dry weather because we still get some high readings, and we're trying to get the bottom of why this happens, but it's looking hopeful for the future!
In December we dye tested the wastewater systems throughout the area bordered by Collingwood, Trafalgar, Bridge and Halifax Streets and found no leakage into the river which is also great news.
The most important thing we can all do to keep the river swimmable is to make sure that only rain goes down the drains. The image above was taken in October by a member of the public who also reported it. It shows the effect of someone washing something out into a stormwater drain somewhere in the CBD. If you see anything you wouldn't want to swim in going down a stormwater drain please phone 546 0200 to report it.