Beachgoers advised to avoid sea
Last updated 05:00 30/03/2011
Water quality at outlying Christchurch beaches is improving, but people should stay out of the surf.
Raw sewage was discharged into the sea to ease pressure on the damaged sewerage system after last month's earthquake.
Health warnings remain in place, despite the improvement.
Environment Canterbury (ECan) surface water quality scientist Michele Stevenson said last week's tests at Spencer Beach, south of the Waimakariri River mouth, returned lower faecal counts.
"The first result a couple of weeks after the earthquake was high and everything since has been low," Stevenson said.
However, she said current flows meant Spencer Beach was still susceptible to contamination and the lower result was unlikely to mean better water quality closer to the city.
"It's quite a distance further north than Waimairi [Beach]," Stevenson said.
"There's a big buffer there. It's a bit hard to know how to relate the two."
Beaches north of the Waimakariri River mouth and on Banks Peninsula south from Port Levy had been cleared for recreational use.
Canterbury medical officer of health Alistair Humphrey said it was unlikely city beaches would be cleared while sewage discharges continued.
"In some places, it's going to be quite some time."
A test at Taylors Mistake last week returned a faecal count under the warnings trigger, but Stevenson said the result was still abnormally high. "For that reason, and due to the real possibility of sewage contamination being washed south around the headland into the bay at Taylors Mistake, we are being cautious," she said.
The faecal count of water samples at beaches from Waimairi to Scarborough were so high, tests were no longer being done.
"Whether it's five times or 50 times over, it doesn't really matter," Stevenson said. "It's a bit of a waste of money at this time.
"Once the discharges stop, that's when we'll start monitoring them again."
Christchurch City Council water and waste manager Mark Christison believed sewage discharges into rivers would continue for several months.
"We are having to renew trunk sewers entirely. They're not quick fixes."
Meanwhile, ECan was developing a plan to measure the ecological effects of discharges into rivers and the Estuary.