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Council Acts on Contaminated Stormwater Discharge

Friday 12 October 2007, 3:40PM

By infonews.co.nz

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TE ANAU

Southland District Council is actively seeking to isolate the cause of an unusuallyhigh recording of bacteria in a stormwater discharge to part of Lake Te Anau.

Project Manager Water and Waste Services Bevan McKenzie said that the high reading was found during routine tests aimed at determining any impacts the stormwater discharges may have on the Lake and to provide information for better future management.

The contamination was found at the Mokoroa Street outfall, which discharges into the Lake. While the programme has tested this and other outfalls many times over the past year, this is the first test to find serious contamination.

He said the level of contamination indicates a sewage input by an unknown means tothe stormwater flow. The test showed the contamination to be present for severalhours during a rainstorm, however from earlier tests, it was determined that the contamination is likely to be intermittent.

As the stormwater system should be free of sewage and such a discharge into the Lake is unacceptable it must be stopped.

Currently the Council is undertaking action to resolve the matter including inspection of the Mokoroa Street catchment in dryconditions and at low stormwater flows, to check for any unusual discharges.

Daily observation of the outflow will be carried out to check for any non stormwater type discharges as well as regular sampling of the outfall to determine if the problem stillexists and also if there is any pattern that emerges.

It is expected that these measures may identify the source, however this is a large stormwater catchment area and further action in the future such as smoke, dye testing and video inspection may also be needed.

The community is asked to help by advisingof anything that they think that may be contributing to the problem.

If they have anysuggestions then please contact the Te Anau Service Centre directly, or by phoning 0800 732 732.

The problem is confined to the township generally east of the Mokoroa Street/Milford Road area and bound by Govan Drive in the north.

Bevan McKenzie said that the frequency of the problem is unknown, but as a precautionary measure, a warning sign will be erected by the Mokoroa Street outfall.

The sign will be removed when tests show there is minimal risk to water users in the vicinity