Rivers dirty after rain
The poor water quality in Far North swimming spots has improved, but Northland Regional Council’s Colin Dall says that the results the regional council obtained in its fifth week of water quality testing serve as a reminder that it is not safe to swim in freshwater after periods of rain.
The regional council’s website posts a warning about swimming.
Before going for a swim, remember these four simple rules:
1/ Don’t swim if there are warning signs indicating water is unsafe
2/ Avoid swimming for two to three days after heavy rainfalls
3/ Don’t swim if water looks dirty or murky, smells, or it has scum on the surface
4/ Be aware of potential sources of contamination nearby or upstream.
‘‘If it’s raining we still sample, but that’s when you are likely to get some elevated bacterial counts,’’ Mr Dall says.
The Waipapa River, at Waihou Valley’s swimming pool; the Kerikeri River, at the Stone Store; Waitangi River, at Wakelins/Watea; and Punakitere, at the Kaikohe Falls swimming hole were notified as unsafe to swim on the regional council’s website last week, after contamination caused by runoff from the land. Tirohanga Stream and the beach at Paihia at the Waitangi Bridge were both listed as potentially unsafe.
‘‘A lot of results this year have been pretty good up until rainfall events, and the flushing off of material from the land,’’ Mr Dall says.
But swimming in freshwater spots in the Far North comes with a warning.
‘‘Generally swimming in the north after a reasonable size rain event is not recommended, just because it will be affected by run off,’’ he says.
‘‘All of this is about risk and just because you swim in that water doesn’t mean you’ll necessarily get sick.’’
The regional council does test to determine where the faecal contaminants in the water are coming from. The regional council undertook ‘‘faecal source tracking’’ in the Kerikeri River during the 2010/2011 and 2011/2012 bathing seasons, and will be doing it again this season.
The 2010/2011 results indicated that wildfowl [birds] were the source of the faecal contamination, whereas the 2011/2012 results indicated ‘‘ruminant’’ animals – sheep, cattle, deer, goats – were the source of the faecal contamination. He says the Waipapa River, in the Puketi Forest, had dangerous levels of Ecoli in the water, most likely because of wild animals.
The council is currently looking at implementing the National Policy Statement for Freshwater Management.
‘‘We will be developing policy in the near future on particular freshwater quality issues,’’ he says.
He says the Waitangi catchment could be employed as a trial area.
There could be considerable costs involved in improving water quality in the region and it could take a long time.