Bacteria levels in the Taieri River at Waipiata, a popular
bathing spot, continue to be up to three times higher than
the national health guidelines, making it unsafe for
Bacteria levels have exceeded the red action guideline of
more than 550 E. coli per 100ml - which indicates the water
poses an unacceptable health risk to swimmers - in every
Otago Regional Council test conducted this summer.
On December 23 1986 E. coli per 100ml was recorded
after significant rainfall two days earlier, but on December
30 it recorded 770 E. coli per 100ml without any
rainfall in the days prior.
Last year the council launched an investigation after
unexplained levels of bacteria were recorded three times
during last summer's recreational monitoring programme.
The regional council monitors the water quality at popular
marine and freshwater bathing sites once a week between
December and March.
It tested for the concentration of E. coli in fresh
water and Enterococci in salty water, which indicated the
presence of faecal material and disease-causing organisms.
Council environmental services manager Martin King said
yesterday two staff last summer investigated the nearby small
tributaries of the river seeking sources of the
contamination, but no obvious source was found.
''It seems it could be a mix of a number of things.''
Many water fowl were seen in the backwaters and there was the
potential for irrigation run-off.
''There's a raft of things really, but we came to no major
Because of recent rain enough mixing was occurring to ensure
the contamination was not at such significant levels
downstream at the river's popular Outram Glen swimming spot,
Mr King said.
The site at Outram had breached the red alert guideline on
December 23, recording 2420 E. coli per 100ml, and
amber alert levels on December 16 and 30 after some rainfall
on those days or the days before.
Staff would meet in coming weeks to analyse the recent data
from Waipiata to see what else could be done, Mr King said.
''There is a bit of work to be done, but to be honest there
is no quick and easy fix.''
The Kakanui River site at Clifton Falls had also continued to
record high levels of bacteria since December 9.
It was found last summer the contamination at this site was
probably because of droppings from nesting gull colonies
upstream of the site.
Other sites to record red action levels of bacteria were the
Clutha River at the Balclutha Lagoon and the Waikouaiti River
at Bucklands Crossing, both on December 9 and 23.