Swimming not recommended

Sewage seeping from old pipes could be causing a spike in E. coli bacteria levels in Blenheim’s Taylor River.

A spot near Blenheim’s amphitheatre, called Riverside, had the worst water quality of the 21 beaches and rivers in Marlborough monitored over summer.

Taylor River was the only site to be given a rating of very poor, meaning swimming was not recommended.

Duck and dog faeces usually caused E.coli elevations but detective work by council environmental scientists had tracked higher bacteria spikes potentially to sewerage leaking from stormwater pipes.

Council environmental scientist Steffi Henkel told the council’s environment committee preliminary results suggested water from stormwater outlets near Riverside had extremely high E.coli concentrations during dry weather conditions.

Several sewage pipelines were identified as potential sources of the contamination.

Damage due to earthquakes and the ageing sewerage system were potentially causing leakage of sewage into the ground and into stormwater pipes, Henkel said.

A number of these sewers were scheduled to be inspected and repaired where necessary.

Dye testing carried out to identify where sewerage pipes were leaking proved inconclusive and a cross-council project team had been set up to deal with the contamination.

Riverside was a popular duck feeding spot.

Environmental science and monitoring manager Alan Johnson said the council could not do much about ducks because they were a wild animal. He reminded people to pick up after their pets.

‘‘Some people chuck dog faeces in the river; out of sight out of mind. Think of the consequence of that. It degrades our waterways.’’

Unsafe E. coli concentrations in the Taylor River during long dry spells had been a regular occurrence in recent summers.