Huge improvement in water quality

Latest bathing water quality monitoring results have shown a marked improvement in the Maitai River around the Collingwood Street Bridge.

The 2009/10 results show the bug count (e-coli per 100ml) averaging 314, less than half the average for the summer of 2008/9, which was 641.

This stretch of the river has been subject to a health warning against swimming since 2007 when regular testing showed a higher than recommended level of e-coli in the water. The source of contamination at the site was finally confirmed as human last year, thanks to a new form of microbial testing carried out by Cawthron Institute.

Council staff then embarked on a comprehensive testing programme throughout the Collingwood and Trafalgar Street stormwater catchments. CCTV cameras were inserted into pipes and dye tests were done to isolate where the contamination was happening. This revealed a portion of the sewerage line in Nile Street had collapsed, allowing sewage to leach into the stormwater system. A further broken sewerage pipe and two cross connections (sewerage pipes mistakenly connected to stormwater pipes) were discovered in Collingwood Street. Repairs of all these issues have now been carried out.

Paul Sheldon, Council’s Monitoring Coordinator says “We are very happy with this result. There has been a significant improvement in water quality since Council invested considerable time and money into finding and fixing the source of contamination. We’ll continue our water quality monitoring in the area and hope that we’ll be able to lift the temporary health warning against swimming in that section of the river.”