Care urged on choosing where to go swimming
South Canterbury's swimming spots appear to mostly be in good shape, but the regional council advises the public to take care.
Environment Canterbury began its water quality monitoring season a fortnight ago. Although an area near the Waihao River, known as the Black Hole, has a warning in place for toxic algae, most of South Canterbury's other spots were marked as "good" or "fair".
However, ECan surface water quality manager Dr Tim Davie said locals should also check the website for results of recent testing.
"We test sites once a week, but if it reaches above trigger levels, we test it again within 48 hours. Those results might not be online while they are being analysed at the laboratory, so we advise caution until the second result is confirmed."
Last week, the Te Moana River at Te Moana Gorge exceeded the recommended health standards for E Coli, but a subsequent test a day later put it below the trigger levels.
"This can happen after a major rain event - faeces from stock could be washed into drains and then the river, for instance, but then get cleared away afterwards," Dr Davie said.
Health warnings were in place at the Opihi, Pareora and Temuka for much of the past three summers because of toxic algal bloom in the waters. The Temuka and Opihi rivers were vulnerable to a drop in quality after a weather change, Dr Davie said.
"There are a few sites which we don't test, because they're either consistently clean or consistently unsuitable for contact and there hasn't been anything to suggest it would change," he said.
The Waihao River below Bradshaws Bridge will not be monitored this season because it has consistently been poor. Meanwhile, ECan has decided not to monitor Lake Opuha at the dam boat ramp and Lake Ruataniwha at the rowing club because of consistently good results.
Dr Davie said "problem sites" could be back on the monitoring list if ECan knew of improvements - such as stock fencing or treatment at public toilets. Similarly, consistently "healthy" sites might be re-examined if there was evidence of increased development in the area.
Dr Davie said the trigger levels for "secondary contact", such as boating, or paddling in the waters, were higher.
- The Timaru Herald