Weekly samples monitor water safety
Have you ever seen a helicopter hovering low over the water at the beach? Chances are it’s the council water quality monitoring team. Reporter Karina Abadia found out more about the work they do.
No-one likes to think they’re swimming in polluted waters. Thankfully there is a team of people making sure that doesn’t happen.
The water quality monitoring programme Safeswim, set up in 1999, runs for 21 weeks annually from the first week of November to the end of March.
More than 95 per cent of water samples collected in the region comply with Ministry for the Environment guidelines, Auckland Council environmental health principal specialist Sharon Tang says.
‘‘Most of our beaches including the eastern beaches are quite safe to swim.
‘‘But we do have some rare occasions where there is a failed result.’’
Every Tuesday samples are taken from 63 Auckland beaches and six freshwater sites, mostly by helicopter.
This makes sense in terms of consistency and timeliness as everything can be done on one day, Ms Tang says.
The samples are analysed at Watercare and results returned to Safeswim within 24 hours. Watercare looks at enterococci bacteria levels in sea water.
The ministry defines the alert level as 140 enterococci to 100ml of water. If a test shows a reading between 140 and 280 enterococci, further testing is carried out until the results return to normal.
When two consecutive levels are more than 280, signs are put up at the beach advising people not to swim.
But if the initial reading is above 1000, signs are put up straightaway, she says.
There have been a couple of incidents this month at central Auckland beaches.
Signs went up at Judges Bay for a couple of days last week after testing revealed a reading of 1800 enterococci.
Swimming was not advised at Mission Bay on January 8 after a reading of 3000 enterococci was recorded.
The levels were back to normal within two days.
Regional and environmental control manager Marcus Herrmann says there are various potential causes of contamination.
‘‘There can be overflows that occur from the wastewater system into the stormwater system; there can be illegal discharges from boats and you can also get animal effluent from pets, birds and ducks.’’
Some advice to swimmers is generally not to swim 24 to 48 hours after heavy rain, take care not to swim too close to outfalls and check the Safeswim website for updates.
Water testing: The Safeswim team use a helicopter to take weekly water samples at beaches around Auckland to test for bacteria.